tag:blogger.com,1999:blog-78835346030157332252018-02-14T03:24:26.426-08:00Computer Networks For AllComputer Networks For All is a blog founded with the intention to provide students of computer networks and candidates for Cisco certifications exams with written and video lessons, as well as quizzes and exams to test their understanding. It covers computer networks from scratch, that is, you can learn networks even if you have no background in the field.M. Bouftiranoreply@blogger.comBlogger71125tag:blogger.com,1999:blog-7883534603015733225.post-28775651311323258092018-01-01T18:35:00.001-08:002018-01-31T18:02:07.373-08:00Latest CCNA 200-125 (V3.0) dump in 2018<div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-P_kan71GxJM/Wkru7dbFxWI/AAAAAAAACiY/Oj4pXbyvCewKusVGhqYb3UaVmUnqIuaAwCLcBGAs/s1600/Latest%2BCCNA%2B200-125%2B%2528V3.0%2529%2Bdump%2Bin%2B2018.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://3.bp.blogspot.com/-P_kan71GxJM/Wkru7dbFxWI/AAAAAAAACiY/Oj4pXbyvCewKusVGhqYb3UaVmUnqIuaAwCLcBGAs/s640/Latest%2BCCNA%2B200-125%2B%2528V3.0%2529%2Bdump%2Bin%2B2018.png" width="640" /></a></div><br /><div style="text-align: justify;">The post of today grants you the latest <b>CCNA 200-125 dump</b> in <b>2018</b> which will greatly facilitate your preparation for the test.&nbsp;<b><b><b>CCNA</b></b> R&amp;S dump</b> contains several questions that you might be in front of in the day of the exam. As I always say,&nbsp;<b><b>CCNA 200-125</b> </b>is by no means to be equated with cheating, for it is aimed at making the test plain for CCNA candidates, and to help students have a picture of how the test looks like. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />&nbsp;A candidate being able to correctly answer all of the questions encompassed in&nbsp;<b><b><b>CCNA</b></b> R&amp;S dump</b> is very likely to pass the exam with flying colors, so if I were you, I would jump at the chance to get a high score. Certainly,&nbsp;<b><b><b>CCNA</b></b> 200-125</b> dumps are not intended for people who didn't study&nbsp;<b><b><b>CCNA</b></b> R&amp;S</b> at all. Cisco&nbsp;<b><b><b>CCNA</b></b> 200-125</b> dumps only help you to reinforce what you have learned and gives you an idea of how the exam is like.<br /><br />Cisco <b>CCNA 200-125</b> dump embraces<b> CCNA 200-125</b> questions, multiple choices, and answers along with explanations to each individual question, so that if you do not know why a question was answered in such a way, the illustration contained would make it simpler and easier for you to grasp. Labs are also included.&nbsp;</div><div style="text-align: justify;"><br />So I disclaim any responsibility for an inappropriate use of this post, or republishing its content unfaithfully. Again,&nbsp;<b><b><b>CCNA</b></b> R&amp;S dump </b>is only there to help you out in getting ready for the exam.</div><div style="text-align: justify;"><br />I would like to point out that this post will be periodically updated whenever there is a new&nbsp;<b><b>CCNA 200-125</b> </b>dump, thus it is important for you to subscribe to the website through the facebook page wherein novel posts are usually shared.</div><div style="text-align: justify;"></div><div style="text-align: center;"><span style="font-size: medium;">You can download&nbsp;</span><span style="font-size: medium;"><b><b>CCNA 200-125</b> dump</b> from below</span><br /><div style="text-align: center;">[post_ad] </div><div style="text-align: left;"><a href="http://www.mediafire.com/file/ys6iksnmm882314/Latest%20CCNA%20200-125%20%28V3.0%29%20dump%20in%202018.pdf" target="_blank"><span style="font-size: xx-small;">Link</span></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"><span style="font-size: medium;"><span style="font-size: x-small;">Related keywords:</span> <span style="font-size: xx-small;">ccna certification, ccna training, cisco certification, cisco training, cisco certifications, cisco ccna certification, ccna training online, ccnp certification, ccna college course, cisco training uk, cisco certification training, ccna training course, ccna certification classes, cisco classes, online ccna certification, ccna cisco certification, cisco certification online, ccna classes near me, best ccna training, cisco ccna training online, cisco ccna boot camp, ccna classes online, ccna certification path, ccna certification training online, ccna certification cisco, online cisco courses, where to get ccna certification, cisco engineer training, cisco certification schools, online ccna classes.</span></span></div></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-92190946502845290072017-10-04T10:41:00.000-07:002017-10-04T17:29:52.617-07:00Latest Cisco ICND2 200-105 dump (v3.0) 2017<div dir="ltr" style="text-align: left;" trbidi="on"><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-aQibvDbZebM/WdUcTgfJKsI/AAAAAAAAChc/z0GhLzexLGUmvY78n4nATxGEoKGZjPo1gCLcBGAs/s1600/latest%2Bcisco%2Bicnd2%2B200-105%2Bdump.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="339" data-original-width="509" height="426" src="https://3.bp.blogspot.com/-aQibvDbZebM/WdUcTgfJKsI/AAAAAAAAChc/z0GhLzexLGUmvY78n4nATxGEoKGZjPo1gCLcBGAs/s640/latest%2Bcisco%2Bicnd2%2B200-105%2Bdump.jpg" width="640" /></a></div><br /><div style="text-align: justify;">Welcome to <b>Computer Networks For All </b>website, where the latest Cisco's exams dumps are periodically shared. In this article I will provide you with the latest Cisco<b> Interconnecting Cisco Networking Devices Part 2 dump in 2017</b>. Such exam is highly taken by computer networks starters. So it is such a golden opportunity to be one of the first websites to share this dump.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">It is noteworthy that ICND2 200-105 dump is not to be deemed as a way of cheating in the exam, for they contain questions which are not guaranteed to be included in the 200-105 test. Thus, all the questions encompassed in ICND2 200-105 dump are only there for the purpose of training and preparation for the test.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">200-105 dump has always proven to be a powerful training tool, on the grounds that it opens up an opportunity for candidates to measure their grasp of the material embodied in the second part of CCNA course, which is ICND2. It is also useful for candidates who wish to know what kind of questions the exam comprises, as well as how the exam looks like.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">All in all, ICND2 200-105 dump should not be ignored by ICND2 test takers; otherwise, they would miss a treasure which will immensely assist them in girding themselves for the exam. According to hundreds of students who have taken this test, CND2 200-105 dump plays a crucial part in terms of clearing things up for candidates, as well as consolidating their understanding of the topics covered in their training material. They also state that ICND2 200-105 dump multiplies students chances to get the certificate with high scores.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Computer Networks For All website constantly adds posts concerning Cisco dumps whenever there is a new dump available, so it would be much better for you to keep up with the up-to-the-minute website posts by means of either liking the Facebook page or subscribing to the associated Youtube channel.</div><br /><div style="text-align: center;"><b><span style="font-size: large;">&nbsp;You can get your <span style="color: red;">ICND2 200-105 dump</span> from below</span></b></div><div style="text-align: center;"></div>[post_ad]<br /><span style="font-size: xx-small;"><span style="color: yellow;"><a href="http://www.mediafire.com/file/fnxa98div3449hz/Latest+ICND2+200-105+dump.pdf" rel="nofollow" target="_blank">link </a></span></span></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-89815221728576709252017-10-04T10:36:00.000-07:002017-10-06T07:25:23.766-07:00Latest Cisco ICND1 100-105 dump (v3.0) 2017<div dir="ltr" style="text-align: left;" trbidi="on"><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-8yUuoucT-pA/WdUaP_AjbNI/AAAAAAAAChQ/I-1SNJTqOJEK_TL1RhK9P7pmwF3PdFIfQCLcBGAs/s1600/Latest%2Bcisco%2Bicnd1%2B100-105.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="339" data-original-width="509" height="426" src="https://2.bp.blogspot.com/-8yUuoucT-pA/WdUaP_AjbNI/AAAAAAAAChQ/I-1SNJTqOJEK_TL1RhK9P7pmwF3PdFIfQCLcBGAs/s640/Latest%2Bcisco%2Bicnd1%2B100-105.jpg" width="640" /></a></div><div style="text-align: justify;"><br />Welcome to <b>Computer Networks For All</b> website, where the latest Cisco's exams dumps are periodically shared. In this article I will provide you with the latest Cisco <b>Interconnecting Cisco Networking Devices Part 1 dump in 2017</b>. Such exam is highly taken by computer networks starters. So it is such a golden opportunity to be one of the first websites to share this dump.<br /><br />It is noteworthy that ICND1 100-105 dump is not to be deemed as a way of cheating in the exam, for they contain questions which are not guaranteed to be included in the 100-105 test. Thus, all the questions encompassed in ICND1 100-105 dump are only there for the purpose of training and preparation for the test.<br /><br />100-105 dump has always proven to be a powerful training tool, on the grounds that it opens up an opportunity for candidates to measure their grasp of the material embodied in the first part of CCNA certificate, which is ICND1. It is also useful for candidates who wish to know what kind of questions the exam comprises, as well as how the exam looks like.<br /><br />All in all, ICND1 100-105 dump should not be ignored by ICND1 test takers; otherwise, they would miss a treasure which will immensely assist them in girding themselves for the exam. According to hundreds of students who have taken this test, CND1 100-105 dump plays a crucial part in terms of clearing things up for candidates, as well as consolidating their understanding of the topics covered in their training material. They also state that ICND1 100-105 dump multiplies students chances to get the certificate with high scores.</div><br /><div style="text-align: center;"><b><span style="font-size: large;">&nbsp;You can get your <span style="color: red;">ICND1 100-105 dump</span> from below</span></b></div><br />[post_ad] <br /><div style="text-align: center;"></div><span style="color: yellow;"><span style="font-size: xx-small;"><a href="http://www.mediafire.com/file/qm1ctnuywzys64s/Latest+ICND1+100-105+dump.pdf" rel="nofollow" target="_blank">link </a></span></span></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-86610295496758483052017-08-29T17:53:00.000-07:002017-08-30T16:03:12.273-07:00Latest CCIE 400-101 (R&S-V5.0) dump 2017<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-ji38uJYya9Q/WaYKySK5STI/AAAAAAAAChA/bH04UUWFVxQHP50xTceoQhPfOmif4HfFQCLcBGAs/s1600/CCIE-400-101-dump.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="400" data-original-width="704" height="362" src="https://4.bp.blogspot.com/-ji38uJYya9Q/WaYKySK5STI/AAAAAAAAChA/bH04UUWFVxQHP50xTceoQhPfOmif4HfFQCLcBGAs/s640/CCIE-400-101-dump.jpg" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">The post of today grants you the <b>CCIE 400-101</b> latest <b>dump</b> which will greatly facilitate your preparation for the test. <b>CCIE R&amp;S dump</b> contains several questions that you might be in front of in the day of the exam. As I always say, <b>CCIE 400-101 </b>is by no means to be equated with cheating, for it is aimed at making the test plain for CCIE candidates, and to help students have a picture of how the test looks like.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />So I disclaim any responsibility for an inappropriate use of this post, or republishing its content unfaithfully. Again, <b>CCIE R&amp;S dump </b>is only there to help you out in getting ready for the exam.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">&nbsp;A candidate being able to correctly answer all of the questions encompassed in <b>CCIE R&amp;S dump</b> is very likely to pass the exam with flying colors, so if I were you, I would jump at the chance to get a high score. Certainly, <b>CCIE 400-101</b> dumps are not intended for people who didn't study <b>CCIE R&amp;S</b> at all. Cisco <b>CCIE 400-101</b> dumps only help you to reinforce what you have learned and gives you an idea of how the exam is like.<br /><br />Cisco <b>400-101</b> dump embraces <b>CCIE 400-101</b> questions, multiple choices, and answers along with explanations to each individual question, so that if you do not know why a question was answered in such a way, the illustration contained would make it simpler and easier for you to grasp. Labs are also included. <br /><br />I would like to point out that this post will be periodically updated whenever there is a new <b>CCIE 400-101 </b>dump, thus it is important for you to subscribe to the website through the facebook page wherein novel posts are usually shared.</div><div style="text-align: justify;"><br /></div><div style="text-align: center;"><span style="font-size: large;">You can download <b>CCIE 400-101 dump</b> from below</span></div>[post_ad]<br /><div style="text-align: right;"><span style="font-size: xx-small;"><a href="https://www.mediafire.com/file/9j5uai4lr1ll5nn/CCIE-400-101-dump.pdf" target="_blank">link</a></span></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-59875241559393472712017-08-16T19:52:00.000-07:002017-08-24T17:39:28.157-07:0006: Session layer - Dialog separation - part 4 (video)<div dir="ltr" style="text-align: left;" trbidi="on"><div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-hyp22BgtkFE/WZUCieg_bNI/AAAAAAAACgw/JsAYH2gxvnoFO99hNA7IhZqwWAL8hdxiwCLcBGAs/s1600/Session%2Blayer%2Bdialog%2Bseparation.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="362" data-original-width="640" height="362" src="https://4.bp.blogspot.com/-hyp22BgtkFE/WZUCieg_bNI/AAAAAAAACgw/JsAYH2gxvnoFO99hNA7IhZqwWAL8hdxiwCLcBGAs/s640/Session%2Blayer%2Bdialog%2Bseparation.jpg" width="640" /></a></div><br /><div style="text-align: justify;">This video lesson covers a service called dialog separation provided by the session layer. It is responsible for solving problems that may occur during data transmission. It allows users to resume data transfer from where an error happens without any need to start over. watch the following video to understand all that.</div><br /><br /></div><div style="height: 0; padding-bottom: 56.25%; position: relative;"><iframe allowfullscreen="" frameborder="0" height="360" src="https://www.youtube.com/embed/KGmakqwUhiw?ecver=2" style="height: 100%; left: 0; position: absolute; width: 100%;" width="640"></iframe></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" target="_blank"><img alt="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" border="0" data-original-height="62" data-original-width="320" src="https://1.bp.blogspot.com/-xKpbX2AgcCU/WZUA61lfWiI/AAAAAAAACgo/yx3J5yRF0SsLxED3X2gNIu3M7Ojq5-KqQCEwYBhgL/s1600/written-lesson.png" /></a></div>[post_ad]</div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-33864584085978478842017-08-16T19:37:00.001-07:002017-08-24T17:39:16.052-07:0006: Session layer - Dialog control - part 3 (video)<div dir="ltr" style="text-align: left;" trbidi="on"><div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-w9hTng-pjP0/WZT_e35RSuI/AAAAAAAACgY/kGwdJtlfXJYaMaLQA8shzf9H5mR1ycbiACLcBGAs/s1600/Session%2Blayer%2Bdialog%2Bcontrol.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="362" data-original-width="640" height="362" src="https://4.bp.blogspot.com/-w9hTng-pjP0/WZT_e35RSuI/AAAAAAAACgY/kGwdJtlfXJYaMaLQA8shzf9H5mR1ycbiACLcBGAs/s640/Session%2Blayer%2Bdialog%2Bcontrol.jpg" width="640" /></a></div><br /><div style="text-align: justify;">This video lesson covers a very important service taking place at the session layer. It is dialog control, a service responsible for determining the type of connection being used, and how the connection to be dealt with. watch the following video to widen your horizon concerning dialog control.</div><div style="text-align: justify;"><br /></div></div><div style="height: 0; padding-bottom: 56.25%; position: relative;"><iframe allowfullscreen="" frameborder="0" height="360" src="https://www.youtube.com/embed/YRudnFZ_zkY?ecver=2" style="height: 100%; left: 0; position: absolute; width: 100%;" width="640"></iframe></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" target="_blank"><img alt="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" border="0" data-original-height="62" data-original-width="320" src="https://2.bp.blogspot.com/-xKpbX2AgcCU/WZUA61lfWiI/AAAAAAAACgk/dTJia8jehFQtQML3S5cYKrfd5MMNFEqZQCLcBGAs/s1600/written-lesson.png" /></a></div>[post_ad]</div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-22190519632496491842017-08-12T10:53:00.000-07:002017-08-24T17:39:01.579-07:0006: Session layer - Authentication & Authorization - part 2 (video)<div dir="ltr" style="text-align: left;" trbidi="on"><div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-2jTRARUjIWU/WY9ANHtqxII/AAAAAAAACgI/01I0m0eIWMEP6RhmbBYjmyMzKp2x4ep1ACLcBGAs/s1600/session-layer-authentication-authorization.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="363" data-original-width="641" height="362" src="https://3.bp.blogspot.com/-2jTRARUjIWU/WY9ANHtqxII/AAAAAAAACgI/01I0m0eIWMEP6RhmbBYjmyMzKp2x4ep1ACLcBGAs/s640/session-layer-authentication-authorization.png" width="640" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><br /></div><div style="text-align: justify;">This video lesson covers two significant services provided by the session layer. Authentication and authorization are the first step that a user undergoes when attempting to access some secured remote resources. Their basic function is to protect users' files on a given server from being accessed by other users. To have a full pictures of they mean, please watch this video below.</div><div style="text-align: justify;"><br /></div></div><div style="height: 0; padding-bottom: 56.25%; position: relative;"><iframe allowfullscreen="" frameborder="0" height="360" src="https://www.youtube.com/embed/UpXtVAmYJuQ?ecver=2" style="height: 100%; left: 0; position: absolute; width: 100%;" width="640"></iframe></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" target="_blank"><img alt="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" border="0" data-original-height="62" data-original-width="320" src="https://1.bp.blogspot.com/-HIKPZ3YRB4Q/WY8hkQSN1qI/AAAAAAAACfk/X6Rt2CqcAeQYtDp-lmdUsbihqmWj3LEVQCEwYBhgL/s1600/written-lesson.png" /></a></div>[post_ad]</div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-16082796896275395412017-08-12T09:29:00.000-07:002017-08-24T17:38:26.485-07:0006: Session layer - Layer 5 of OSI model - part 1 (video)<div dir="ltr" style="text-align: left;" trbidi="on"><div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-YC3_mCgX4tQ/WY8sFe_NXbI/AAAAAAAACfw/bgT3K30SPQwxBGw432x3lCDHUVVemNlUgCLcBGAs/s1600/Session%2Blayer.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="362" data-original-width="640" height="362" src="https://1.bp.blogspot.com/-YC3_mCgX4tQ/WY8sFe_NXbI/AAAAAAAACfw/bgT3K30SPQwxBGw432x3lCDHUVVemNlUgCLcBGAs/s640/Session%2Blayer.png" width="640" /></a></div><br /></div><div style="text-align: justify;">This lesson is an introduction to session layer, wherein I elucidate the basic functions of the layer. Light is shed on some underlying concepts associated with the layer. These concepts play a so crucial role in data transmission that they are involved in paving the way for transmission, opening, managing, and terminating communication between end-user application processes. Watch the video below to have a full grasp of what has been said.</div><br /><div style="height: 0; padding-bottom: 56.25%; position: relative;"><iframe allowfullscreen="" frameborder="0" height="360" src="https://www.youtube.com/embed/yGqNs9o9-2E?ecver=2" style="height: 100%; left: 0; position: absolute; width: 100%;" width="640"></iframe></div></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" target="_blank"><img alt="http://www.easteaglefoundation.org/?download=2016/08/06-session-layer-layer-5-of-osi-model.html" border="0" data-original-height="62" data-original-width="320" src="https://2.bp.blogspot.com/-HIKPZ3YRB4Q/WY8hkQSN1qI/AAAAAAAACfg/a4afvUZCMPIWEv0S0paVeT_ODmsmUOeUACLcBGAs/s1600/written-lesson.png" /></a></div>[post_ad]</div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-15347840109702690222017-08-01T18:29:00.001-07:002017-08-01T18:46:46.451-07:00Exclusive ! latest CCNP 300-101 (R&S) dump 2017<div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-r49oSzPvHtY/WYEokba2o1I/AAAAAAAACeY/1DwiRUMG_BcHN0I5qVl-I4BNYU0xyvcTgCLcBGAs/s1600/CCNP%2B300-101%2Bdump.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="400" data-original-width="704" height="362" src="https://2.bp.blogspot.com/-r49oSzPvHtY/WYEokba2o1I/AAAAAAAACeY/1DwiRUMG_BcHN0I5qVl-I4BNYU0xyvcTgCLcBGAs/s640/CCNP%2B300-101%2Bdump.jpg" width="640" /></a></div><br /><div style="text-align: justify;">&nbsp;Once again, This<b> CCNP 300-101 dump</b> is not to be regarded as way of cheating on the grounds that the questions contained are only there to help <b>CCNP 300-101</b> candidates to have an idea of the exam as well as practice what they know in this regard. Furthermore, a person to take <b>CCNP R&amp;S</b> test must have already girded themselves up for the test, so not everyone can make use of this dump. Hence, The dump is to be perceived as a mock exam which helps students to visualize the test.<br /><br />A <b>CCNP 300-101 dump's</b> candidate who is able to answer all of the questions included in the dump correctly, has a greater chance to pass <b>CCNP R&amp;S</b> test. The test is in the form of questions, multiple choices, and answers accompanied with illustrations to each single question. <br /><br />Any new dump regarding<b> CCNP 300-101 </b>will be added to this post, so it is highly recommended for you to join our website by liking its facebook page in which latest news and dumps regarding Cisco exams are on the spot shared.</div><br /><div style="text-align: center;">You can download <b><span style="font-size: large;">CCNP 300-101 dump</span> </b>(in size of 3MB)<b> </b>from below</div><div style="text-align: center;">[post_ad]&nbsp;</div><div style="text-align: center;"><br /></div><div style="text-align: center;"><div style="text-align: left;"><span style="font-size: xx-small;"><a href="http://www.mediafire.com/file/n1fne6yxc4i2pp6/Exclusive_%21_latest_CCNP_300-101_%28R%26S%29_dump_2017.pdf" rel="nofollow" target="_blank">link</a></span></div><div style="text-align: justify;"><span style="color: white;"><span style="font-size: xx-small;"><span style="font-size: xx-small;"><b><span style="font-size: small;">related keywords:</span> </b>ccnp certification, ccnp training, cisco certification, cisco training, cisco certifications, cisco ccnp certification, ccnp training online, ccnp certification, ccnp college course, cisco training uk, cisco certification training, ccnp training course, ccnp certification classes, cisco classes, online ccnp certification, ccnp cisco certification, cisco certification online, ccnp classes near me, best ccnp training, cisco ccnp training online, cisco ccnp boot camp, ccnp classes online, ccnp certification path, ccnp certification training online, ccnp certification cisco, online cisco courses, where to get ccnp certification, cisco engineer training, cisco certification schools, online ccnp classes.</span></span></span></div></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-19084426053118972782017-08-01T17:25:00.001-07:002017-08-01T17:27:34.441-07:0013 : Comparison and contrast of TCP/IP and OSI models<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-wPuJ4Nr9GYA/WYEb3D9PD-I/AAAAAAAACeI/B5US0dsFT04vxDOEXZCG5tWIcTpS-jWxwCLcBGAs/s1600/Comparison%2Band%2Bcontrast%2Bof%2BTCP-IP%2Band%2BOSI%2Bmodels.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://3.bp.blogspot.com/-wPuJ4Nr9GYA/WYEb3D9PD-I/AAAAAAAACeI/B5US0dsFT04vxDOEXZCG5tWIcTpS-jWxwCLcBGAs/s640/Comparison%2Band%2Bcontrast%2Bof%2BTCP-IP%2Band%2BOSI%2Bmodels.png" width="640" /></a></div><br /></div><div class="separator" style="clear: both; text-align: center;"></div><div style="text-align: justify;">As a learner of computer networks, it is of prime importance to be able to identify the differences between TCP/IP model and OSI model. Hence, I am trying, in what follows, to draw a distinction between these two indispensable models as well as delineate each one’s characteristics and significance.</div><div style="text-align: justify;"><br /><span style="font-size: large;"><b>Brief history of TCP/IP</b></span></div><div style="text-align: justify;"><br />Before embarking on a rigorous dissection of <b>TCP/IP model</b> vis-à-vis <b>OSI model</b>, a briefly useful chronicle of TCP/IP model’s rise and development would be crucially substantial in order to have a thorough grasp of the whole issue.&nbsp;</div><div style="text-align: justify;"><br />TCP/IP model, as the name implies, is composed of two elements TCP and IP, which are the first and original protocols in the suite in terms of development. In 1978, it was split into two protocols : TCP and IP. With regard to TCP, standing for Transmission Control Protocol, it is one of the main protocols of the <b>Internet protocol suite</b> ( a set of protocols working together for the purpose of data transmission), including IP, being short for Internet Protocol, which is also a constituent part of the model, playing a central role in the communication of data. Thus TCP and IP protocols are complementary, that is, no one can accomplish a successful transfer of data without the other.</div><div style="text-align: justify;"><br />TCP/IP model was created in the 1970s, long before OSI model, by <b>DARPA </b>(Defense Advanced Research Projects Agency), an agency of the United States Department of Defense specialized in the development of technologies for the sake of the military. That is why it is sometimes referred to as <b>DoD </b>(Department of Defense) model. The first founding name of DARPA was <b>ARPA </b>which was created in 1958 by President Dwight D. Eisenhower as a reaction to the launching of Sputnik, the first satellite to be placed in orbit, by the former Soviet Union. Then the name changed to DARPA in March 1972 to last only few years to be altered again to ARPA in February in 1993, to finally get its final name as DARPA in March 1996.&nbsp;</div><div style="text-align: justify;"><br /><span style="font-size: large;"><b>Comparison and contrast of TCP/IP and OSI models</b></span></div><div style="text-align: justify;"><br />The most obvious contrast between the two models, in terms of the layered diagram, is that TCP/IP model comprises only four layers, whereas OSI model encompasses seven hierarchical layers. Being made of only four layers, the top fourth layer, Application layer (in TCP/IP), is equivalent to the three upper layers in OSI model, which are Application, Presentation, and Session layers. As for the third layer in TCP/IP model, Host-to-Host layer, is corresponding Transport layer in OSI model. However, the second layer of TCP/IP, Internet layer, has altered to Network layer in OSI model. In a similar way, the first layer in TCP/IP, Network Access Layer, corresponds to the Data-Link layer and Physical Layer in OSI model. The following figure sums it all up.</div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-SRYy7kAlX0Q/WWkCOXc-bhI/AAAAAAAACdk/H09WYIta-tEi9YcXEYhoVtP-yI_rmc3vgCLcBGAs/s1600/TCPIP-vs-OSI-models.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="409" data-original-width="727" height="360" src="https://2.bp.blogspot.com/-SRYy7kAlX0Q/WWkCOXc-bhI/AAAAAAAACdk/H09WYIta-tEi9YcXEYhoVtP-yI_rmc3vgCLcBGAs/s640/TCPIP-vs-OSI-models.png" width="640" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><div style="text-align: justify;"><br />A very major difference between the two models is that OSI model is theoretical while TCP/IP is practical ; or, in other words, OSI model is a reference model whereas TCP/IP is an implementation of the former.&nbsp; OSI model is conceptual in the sense that it describes how data transmission occurs between sender and receiver&nbsp; in terms of seven illustrative layers in addition to characterizing and standardizing communication regardless of the nature of the technology being utilized. So the object of OSI model is to enable respective networking devices and systems made by different manufacturers to interoperate.</div><div style="text-align: justify;"><br />In contrast, TCP/IP is the very essence protocol, among others, of the Internet Protocol Suite used for data communication. TCP/IP suite is a set of protocols that are employed in a basic transfer of data, for this reason it is known as a practical model. The protocols included in the suite are put into function in a basic data transport.<br /><div style="text-align: center;"><b>See the next lesson from below </b></div>[post_ad] </div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-67828577883571655692017-07-11T18:28:00.000-07:002017-07-11T18:28:20.540-07:00New ! Cisco 642-732 - CCNP wireless dump <div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-Jj5zQh5f75E/WWOllvpAwqI/AAAAAAAACdQ/ViNm2m8QRfskEIQaFAOw3w0U_Y3N_p8jgCLcBGAs/s1600/New%2B%2521%2BCisco%2B642-732%2B-%2BCCNP%2Bwireless%2Bdump.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://1.bp.blogspot.com/-Jj5zQh5f75E/WWOllvpAwqI/AAAAAAAACdQ/ViNm2m8QRfskEIQaFAOw3w0U_Y3N_p8jgCLcBGAs/s640/New%2B%2521%2BCisco%2B642-732%2B-%2BCCNP%2Bwireless%2Bdump.png" width="640" /></a></div><br /><div style="text-align: justify;">Again, This <b>Cisco 642-732 dump</b> is not to be regarded as way of cheating on the grounds that the questions contained are only there to help CCNP wireless candidates to have an idea of the exam as well as practice what they know in this regard. Furthermore, a person to take CCNP wireless test must have already girded themselves up for the test, so not everyone can make use of this dump. Hence, The dump is to be perceived as a mock exam which helps students to visualize the test.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">A <b>Cisco 642-732 dump's </b>candidate who is able to answer all of the questions included in the dump correctly, has a greater chance to pass CCNP wireless test. The test is in the form of questions, multiple choices, and answers accompanied with illustrations to each single question.&nbsp;</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Any new dump regarding CCNP wireless will be added to this post, so it is highly recommended for you to join our website by liking its facebook page in which lateset news and dumps regarding Cisco exams are on the spot shared.</div><div style="text-align: justify;"><br /></div><div style="text-align: center;">You can download <b>CCNP wireless dump </b>(in size of 1MB)<b> </b>from below</div>[post_ad]<br /><span style="font-size: xx-small;"><a href="https://www.mediafire.com/?4jibw65qdugayil" rel="nofollow" target="_blank">Link </a></span></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-31771280979022843952017-07-09T19:21:00.000-07:002017-07-09T19:21:04.235-07:00How to Make Money Online Using your Computer Networks Knowledge<div dir="ltr" style="text-align: left;" trbidi="on"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w:HyphenationZone>21</w:HyphenationZone> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:DoNotPromoteQF/> <w:LidThemeOther>FR</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>AR-SA</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> 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Accent 3"/> <w:LsdException Locked="false" Priority="73" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Grid Accent 3"/> <w:LsdException Locked="false" Priority="60" SemiHidden="false" UnhideWhenUsed="false" Name="Light Shading Accent 4"/> <w:LsdException Locked="false" Priority="61" SemiHidden="false" UnhideWhenUsed="false" Name="Light List Accent 4"/> <w:LsdException Locked="false" Priority="62" SemiHidden="false" UnhideWhenUsed="false" Name="Light Grid Accent 4"/> <w:LsdException Locked="false" Priority="63" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Shading 1 Accent 4"/> <w:LsdException Locked="false" Priority="64" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Shading 2 Accent 4"/> <w:LsdException Locked="false" Priority="65" SemiHidden="false" UnhideWhenUsed="false" Name="Medium List 1 Accent 4"/> <w:LsdException Locked="false" Priority="66" SemiHidden="false" UnhideWhenUsed="false" Name="Medium List 2 Accent 4"/> <w:LsdException Locked="false" 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Accent 5"/> <w:LsdException Locked="false" Priority="70" SemiHidden="false" UnhideWhenUsed="false" Name="Dark List Accent 5"/> <w:LsdException Locked="false" Priority="71" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Shading Accent 5"/> <w:LsdException Locked="false" Priority="72" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful List Accent 5"/> <w:LsdException Locked="false" Priority="73" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Grid Accent 5"/> <w:LsdException Locked="false" Priority="60" SemiHidden="false" UnhideWhenUsed="false" Name="Light Shading Accent 6"/> <w:LsdException Locked="false" Priority="61" SemiHidden="false" UnhideWhenUsed="false" Name="Light List Accent 6"/> <w:LsdException Locked="false" Priority="62" SemiHidden="false" UnhideWhenUsed="false" Name="Light Grid Accent 6"/> <w:LsdException Locked="false" Priority="63" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Shading 1 Accent 6"/> <w:LsdException Locked="false" 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gte mso 10]><style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tableau Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} </style><![endif]--> <br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-WQjAa1AtM50/WWElINzMljI/AAAAAAAACb4/g8sziM_8l-QPXGm3ihprl4HK0WMPodopACLcBGAs/s1600/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="720" data-original-width="1280" src="https://2.bp.blogspot.com/-WQjAa1AtM50/WWElINzMljI/AAAAAAAACb4/g8sziM_8l-QPXGm3ihprl4HK0WMPodopACLcBGAs/s1600/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge.png" /></a></div><div class="MsoNormal" style="text-align: justify;"><br /></div><div class="MsoNormal" style="text-align: justify;">Do you hold a diploma in computer science or computer networks and you did not find a job&nbsp;? Would you like to <b>make money</b> with your computer skills&nbsp;? do you want to <b>earn a living&nbsp;</b>? do you have a decent knowledge in computer science and you wish to use it to make money online&nbsp;? are you fed up with bombastic titles such as how to make money online in no time, how to be a millionaire in short time, how to earn money from Forex trading (trading online, <span class="spgb-e">stock charts, stock trading, online stock broker etc</span>), how to realize a profit from marketing (selling products), or even how to become an internet marketer with no experience&nbsp;? did you come across terms such as CPA, CPC, RPM, CPM, CTR ways of making money from the internet&nbsp;? in this article I want you to forget about all that and pay careful attention to the strategy that I will share with you, which will totally change your financial situation.</div><div class="MsoNormal" style="text-align: justify;"><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-PgYX2eLspN4/WWI7m1o1zfI/AAAAAAAACc4/WaLIoxPb3TYNI4rCiwbDEWrz5_DhBC2PQCLcBGAs/s1600/How%2Bto%2BMake%2BMoney%2BOnline%2BUsing%2Byour%2BComputer%2BNetworks%2BKnowledge5.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="256" data-original-width="681" height="238" src="https://4.bp.blogspot.com/-PgYX2eLspN4/WWI7m1o1zfI/AAAAAAAACc4/WaLIoxPb3TYNI4rCiwbDEWrz5_DhBC2PQCLcBGAs/s640/How%2Bto%2BMake%2BMoney%2BOnline%2BUsing%2Byour%2BComputer%2BNetworks%2BKnowledge5.png" width="640" /></a></div><br /></div><div class="MsoNormal" style="text-align: justify;">In what follows I will show you a very valuable strategy, derived from my personal experience, you might use to make money by virtue of your computer skills only. To start with, most of you disregard the idea of creating a blog and start writing articles, lessons, making videos, answers to questions, concerning computer networks&nbsp;; however, if you realized how profitable it is, I am pretty sure that you would not let it slip through your fingers. All you need to do is to create a blog using whatever platform you wish such as <a href="http://blogger.com/" rel="nofollow" target="_blank">blogger</a>, <a href="https://wordpress.com/" rel="nofollow" target="_blank">wordpress</a>, or <a href="https://www.tumblr.com/" rel="nofollow" target="_blank">tumblr</a> and start writing your first texts, no matter whether you are good at writing or not, for the very essence of the blog is to share your knowledge nothing else.&nbsp;</div><div class="MsoNormal" style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-BCv_NOrImNk/WWE2N6ylfMI/AAAAAAAACcE/XV4ER1aTMno_tSfz7A5XUHcUFpBDSHWDACLcBGAs/s1600/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="333" data-original-width="681" height="312" src="https://2.bp.blogspot.com/-BCv_NOrImNk/WWE2N6ylfMI/AAAAAAAACcE/XV4ER1aTMno_tSfz7A5XUHcUFpBDSHWDACLcBGAs/s640/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge1.png" width="640" /></a></div><div class="MsoNormal" style="text-align: justify;">You are now asking how I can get paid just by writing articles. After drafting, for example, 20 articles regarding your field of interest, then you will be able to monetize you articles, that is, you can begin earning your first dollar. The most renowned and famous company that the majority of publishers use to monetize their content is <a href="https://www.google.com/adsense/" rel="nofollow" target="_blank">GoogleAdsense</a>. Google has two kinds of users, referred to as advertisers and publishers. As for advertisers, they are those who advertise for their products or services by means of using <a href="http://google.com/adwords" rel="nofollow" target="_blank">Google Adwords</a>. With regard to publishers, they are those who make their websites available for ads of advertisers utilizing Google Adsense, that is to say, publishers promote advertisers’ products and services within their blogs.&nbsp;</div><div class="MsoNormal" style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-nwWd1BXTvWQ/WWGbUzpfY6I/AAAAAAAACcY/LkUVcZDRHrsHSDJb0-4cwrElLorPrI0zQCLcBGAs/s1600/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="333" data-original-width="681" height="312" src="https://4.bp.blogspot.com/-nwWd1BXTvWQ/WWGbUzpfY6I/AAAAAAAACcY/LkUVcZDRHrsHSDJb0-4cwrElLorPrI0zQCLcBGAs/s640/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge2.png" width="640" /></a></div><div class="MsoNormal" style="text-align: justify;">Hitherto you get an idea about how to start. What to do afterwards is to create an account in Google Adsense and link it with your blog. Do not try to use a blog that does not contain enough articles, because Google will not approve it. That is why I mentioned that you need to have at least from 10 to 20 articles in your website. Furthermore, do not try to copy the content from other websites, for it is considered to be plagiarism according to Google’s privacy policy&nbsp;; however, you are allowed to paraphrase the others’ content on the condition that you give credit to the author by making reference. Next, after everything is ready, you need to place ads onto your blog page or inside you articles, which will highly encourage visitors to click on them. Your blog is now well-prepared to be used by visitors. The question to ask at the moment is from where I can come up with traffic&nbsp;? this is answered in the following paragraphs.</div><div class="MsoNormal" style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-HVCkU9SkZLY/WWGffsb1PII/AAAAAAAACcg/pNNpUXG0_g0w10wowlSf1zUN2h0Npv8wQCLcBGAs/s1600/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2BknowledgeHow%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="333" data-original-width="681" height="312" src="https://2.bp.blogspot.com/-HVCkU9SkZLY/WWGffsb1PII/AAAAAAAACcg/pNNpUXG0_g0w10wowlSf1zUN2h0Npv8wQCLcBGAs/s640/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2BknowledgeHow%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge3.png" width="640" /></a></div><div class="MsoNormal" style="text-align: justify;">There are different types of traffic which your blog can have. The very important type is the traffic coming from search engines, because this type will bring to your website a steady number of visitors a day. In other words, once a user search for a given title or keyword which corresponds with yours, your blog will be shown in the first ten results of Google. Nevertheless, this type of traffic entails many characteristics which your content should have, such as authenticity and well-chosen keywords to attract visitors, as well as being indexed in Google and getting nearer to the first ten results. Thus such type of traffic comes gradually with time because it depends on search engines to index your posts. If you keep writing articles, at least few days a week, you will definitely get a mammoth number of visitors from search engines.</div><div class="MsoNormal" style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-F8hS-ZMv9K4/WWGiTtPSyfI/AAAAAAAACco/of2u53VJyw0_ZIaE7CYguonSDlruLYgtACLcBGAs/s1600/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="333" data-original-width="681" height="312" src="https://2.bp.blogspot.com/-F8hS-ZMv9K4/WWGiTtPSyfI/AAAAAAAACco/of2u53VJyw0_ZIaE7CYguonSDlruLYgtACLcBGAs/s640/How%2Bto%2Bmake%2Bmoney%2Bonline%2Busing%2Byour%2Bcomputer%2Bnetworks%2Bknowledge4.png" width="640" /></a></div><div class="MsoNormal" style="text-align: justify;">The second most important type of traffic is social media such as Facebook. This latter has proven to be a powerful source of traffic in recent years to the extent that normal users, publishers, and advertisers tend to immensely use it. By virtue of Facebook you can create a Facebook page and put it within your blog to start accumulating followers and subscribers. Once the Facebook page has a great number of fans, you may share your articles on it and see how much traffic will be driven to your blog. Furthermore, another way to fetch traffic is through Facebook groups where people of a specific interest gather in a given group. Therefore, <span style="mso-spacerun: yes;">&nbsp;</span>you as a blogger, you are able to share your posts within groups, and your blog will be inundated with visitors.&nbsp;</div><div class="MsoNormal" style="text-align: justify;"><br /></div><div class="MsoNormal" style="text-align: center;"><span style="font-size: large;"><b>You can practically apply all what has been mentioned above from <span style="color: red;">A</span> to <span style="color: red;">Z</span> by using this detailed guide <span style="color: red;">below</span>.</b></span></div><div class="MsoNormal" style="text-align: center;">[post_ad]</div><div class="MsoNormal"><span style="font-size: xx-small;"><a href="http://www.mediafire.com/file/85de7gf8n4g49g0/How-to-Start-a-Blog+%28practical+part%29.pdf" rel="nofollow" target="_blank">Link</a></span></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-17809522538866809102017-07-05T09:02:00.000-07:002018-01-01T18:15:53.101-08:00Latest Cisco CCNA 200-125 (V3.0) dump<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-u1fDcM8NsJA/WV0MZpUZAhI/AAAAAAAACbo/Q9gc5zN4Q1QFpX5Ejr1fLpLWo5iGiZ_3gCLcBGAs/s1600/Latest%2BCisco%2527s%2BCCNA%2B200-125%2B%2528V3.0%2529%2Bdump%2Bof%2B2017.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://1.bp.blogspot.com/-u1fDcM8NsJA/WV0MZpUZAhI/AAAAAAAACbo/Q9gc5zN4Q1QFpX5Ejr1fLpLWo5iGiZ_3gCLcBGAs/s640/Latest%2BCisco%2527s%2BCCNA%2B200-125%2B%2528V3.0%2529%2Bdump%2Bof%2B2017.png" width="640" /></a></div><br />First I would like to declare that <b>Cisco 200-125 dump</b> is not to be considered as a means of cheating in the test, for it contains questions of a previously done exam. However, most of the time many questions asked in a preceding exam are somewhat repeated either in the same formulation or paraphrased.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">A candidate being able to correctly answer all of the questions encompassed in <b>Cisco 200-125 dump</b> is very likely to pass the exam with flying colors, so if I were you, I would jump at the chance to get a high score. Of course, Cisco 200-125 dumps are not intended for people who didn't study CCNA 200-125 at all. Cisco 200-125 dumps only help you to reinforce what you have learned and gives you an idea of how the exam is like.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><b>Cisco 200-125 dump</b> embraces CCNA 200-125 (V3.0) questions, multiple choices, and answers along with explanations to each individual question, so that if you do not know why a question was answered in such a way, the illustration contained would make it simpler and easier for you to grasp. Labs are also included.&nbsp;</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">I would like to point out that this post will be periodically updated whenever there is a new <b>Cisco 200-125 dump</b>, thus it is important for you to subscribe to the website through the facebook page wherein novel posts are usually shared.</div><div style="text-align: justify;"><br /></div><div style="text-align: center;"><b>Cisco 200-125 dump</b> is in the form of PDF<b> </b>in size of 1MB available to be downloaded from below</div><div style="text-align: center;">[post_ad]</div><div style="text-align: center;"><div style="text-align: left;"><span style="font-size: xx-small;"><a href="https://www.mediafire.com/?p787l7juaet0d54" rel="nofollow" target="_blank">Link</a></span></div><br /><div style="text-align: justify;"><span style="font-size: xx-small;"><span style="font-size: x-small;"><b><span style="font-size: small;">related keywords:</span> </b>ccna certification, ccna training, cisco certification, cisco training, cisco certifications, cisco ccna certification, ccna training online, ccnp certification, ccna college course, cisco training uk, cisco certification training, ccna training course, ccna certification classes, cisco classes, online ccna certification, ccna cisco certification, cisco certification online, ccna classes near me, best ccna training, cisco ccna training online, cisco ccna boot camp, ccna classes online, ccna certification path, ccna certification training online, ccna certification cisco, online cisco courses, where to get ccna certification, cisco engineer training, cisco certification schools, online ccna classes.</span></span></div></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-50974072406682871662017-07-02T08:17:00.001-07:002017-07-02T08:17:43.186-07:0012: Cabling - Coaxial & optical fiber cables part 3<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><br /><div class="separator" style="clear: both; text-align: center;"><span style="font-size: large;"><b><a href="https://1.bp.blogspot.com/-C_84j3PFQcE/WVfBhrKISUI/AAAAAAAACbY/7RmmDv5DIYgTFqCdCRGpkrTQucfEwPcIwCLcBGAs/s1600/Coaxial-and-fiber-optics.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1000" data-original-width="1600" height="400" src="https://1.bp.blogspot.com/-C_84j3PFQcE/WVfBhrKISUI/AAAAAAAACbY/7RmmDv5DIYgTFqCdCRGpkrTQucfEwPcIwCLcBGAs/s640/Coaxial-and-fiber-optics.png" width="640" /></a></b></span></div><br /><br /><span style="font-size: large;"><b>Coaxial cable</b></span><br /><br />Coaxial, also referred to as coax, is one of the oldest cables that has been used for data transmission. It has been widely used in LANs in the past. It consists of a single&nbsp; coated copper wire in the center, an outer mesh made of metal that has two functions which are conducting voltage and reducing outside interference, and an outer jacket made of plastic. Coaxial cable is also used in wireless communication linking antennas to wireless devices. Moreover, the cable is widely utilized for connecting dishes to TV receptor. The following figure reveals the coaxial cable along with its connectors. <b>For more details about coaxial cable, see the previously explained lesson about <a href="http://www.easteaglefoundation.org/?download=2016/12/ethernet-what-is-ethernet.html" target="_blank">Ethernet</a>.</b><br /><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-Ak-cXbMNL9c/WVe50c-zl2I/AAAAAAAACbM/TBMWEN2DKkYuzcACpTUtgvEWX7omp_8_wCLcBGAs/s1600/Coaxial%2Band%2Bconnectors.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="395" src="https://3.bp.blogspot.com/-Ak-cXbMNL9c/WVe50c-zl2I/AAAAAAAACbM/TBMWEN2DKkYuzcACpTUtgvEWX7omp_8_wCLcBGAs/s640/Coaxial%2Band%2Bconnectors.png" width="640" /></a></div><br /><br /><span style="font-size: large;"><b>Optical fiber cable</b></span><br /><br />Optical fiber is another different type of cable that is also used for data transfer. This cable is characterized by high-speed data transmission with greater bandwidth, that is to say, data is traveled through this cable much faster than either UTP, STP, or Coaxial. That is because fiber optics uses light pulses instead of electrical voltage used by other types of cable. Moreover, this cable is perfectly suitable for long distances, without needing any signal enhancer, especially which are counted by kilometers. Data transmitted through this cable is much securer and safer than the other cables. It is commonly used to link wide area networks such as two networks located in different cities or countries. <br /><br />Fiber exists in varying types, each one has some features that differ it from the other. <b>Single-Mode</b> and <b>Multi-mode</b> fiber-optic cable are two basic types that are not the same in the way they carry light pulses. The following figure displays the two distinctive types of fiber optics.<br /><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-xx65lbO63YA/WVe3op2dkUI/AAAAAAAACbE/9c8nUs_wRa8nF7eXfDx6P45Qzs8i6cylQCLcBGAs/s1600/single-mode-fiber-vs-multimode-fiber.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="371" data-original-width="1206" height="196" src="https://1.bp.blogspot.com/-xx65lbO63YA/WVe3op2dkUI/AAAAAAAACbE/9c8nUs_wRa8nF7eXfDx6P45Qzs8i6cylQCLcBGAs/s640/single-mode-fiber-vs-multimode-fiber.png" width="640" /></a></div><br />As you see in the above figure, in single-mode fiber, light pulses travel in a single straight path, whereas in Multi-mode fiber, light pulses make their way along the cable through multiple paths. Significantly, single-mode fiber can be stretched up to about 100 km, whilst Multi-mode fiber supports shorter distances reaching up to 2 km. They also vary in the light source or the generator of light which can be either <b>Light Emitting Diode</b> <b>(LED)</b> or lasers. Whereas single-mode fiber uses lasers as light source, Multi-mode fiber relies on LEDs as a source of light.<br /><br />A single core of fiber can carry data only in one direction, and&nbsp; to carry data in two directions simultaneously, usually a fiber-optic cable with two cores is required. Concerning the health of network installers,&nbsp; single-mode fiber using lasers is dangerous for the human eye because of the intense of the light to the extent that eyes can be damaged. Thus when installing or troubleshooting such cable, due care is required. <br /><br />Using this cable in networks needs a large budget on the grounds of the expensive receiving devices, known as photodiodes, as well as the big amount of money that the engineer or technician require in order to install the network because to link a network utilizing fiber optics needs special training.<br /><br /><div style="text-align: center;"><b>See the next lesson from here </b></div>[post_ad] </div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-26772400554368777792017-06-27T06:14:00.000-07:002017-06-27T06:20:36.107-07:0012: Cabling - UTP and STP cables part 2<div dir="ltr" style="text-align: left;" trbidi="on"><span style="font-size: large;"><b></b></span><br /><div class="separator" style="clear: both; text-align: center;"><span style="font-size: large;"><b><a href="https://3.bp.blogspot.com/-3zu6Ht-Xxvg/WVJYgkUZLNI/AAAAAAAACa0/Piqw9ymQq3E-Vu1SLJWkMnD8DouFoXsdgCLcBGAs/s1600/cabling-STP-UTP-cables.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1000" data-original-width="1600" height="400" src="https://3.bp.blogspot.com/-3zu6Ht-Xxvg/WVJYgkUZLNI/AAAAAAAACa0/Piqw9ymQq3E-Vu1SLJWkMnD8DouFoXsdgCLcBGAs/s640/cabling-STP-UTP-cables.png" width="640" /></a></b></span></div><br /><span style="font-size: large;"><b>Unshielded Twisted-Pair (UTP) cable</b></span><br /><br /><div style="text-align: justify;">To begin with, Unshielded Twisted-Pair (UTP), the most common media.&nbsp; In Ethernet, UTP comprises eight wires with each two wires twisted together and put inside a cable jacket. See the following figure.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-VrEJO2pURCI/WVI3HRGP11I/AAAAAAAACZM/uzX33h7O-xcSVM_sKc-arSEqcOuIMp9PgCLcBGAs/s1600/Unshielded%2Btwisted-pair-UTP.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="197" data-original-width="523" height="150" src="https://2.bp.blogspot.com/-VrEJO2pURCI/WVI3HRGP11I/AAAAAAAACZM/uzX33h7O-xcSVM_sKc-arSEqcOuIMp9PgCLcBGAs/s400/Unshielded%2Btwisted-pair-UTP.png" width="400" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-dx7_ZiRqhPY/WVJRlK3E9gI/AAAAAAAACaI/K2HcfUb_LWEEeNWLolvTMYK-KrTPFjdmQCLcBGAs/s1600/twisted%2Bpair.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="304" data-original-width="477" height="252" src="https://3.bp.blogspot.com/-dx7_ZiRqhPY/WVJRlK3E9gI/AAAAAAAACaI/K2HcfUb_LWEEeNWLolvTMYK-KrTPFjdmQCLcBGAs/s400/twisted%2Bpair.png" width="400" /></a></div><br /><div style="text-align: justify;">The reason behind twisting each two pairs is to keep the cable away from the influence of outside interference. Because of the fact that each wire in the pair carries signals in the opposite direction, the task of twisting them leads the magnetic fields on the wire pair to cancel each other. The act of being interfered by the magnetic field on the wire pair is referred to as <b>cross-talk</b>.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">UTP cable has several categories which have started evolving since the past few years. The differences between the categories vary in the level of bandwidth defined by IEEE and, the quality of cable, and the protection level against interference. The most renowned UTP cable categories start from Category 3 (Cat 3) to Category 5 (Cat 5) ; such categories support the speed rate of 100 megabit per second. In the next few years after Cat 5, specifically in 1999, another category, Category 5e (Cat 5e), emerged. Enhancing Cat 5 to Cat 5e has brought new&nbsp; improvement in terms of the nature of data transmission, lying in enabling full-duplex Fast Ethernet gigabit transmission.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">After Cat 5e, another UTP cabling catergory came into existence in 2002, which is Cat 6. This UTP category is so strong and advanced that works at high performance and reducing&nbsp; the cross-talk that occurs between cables at the moment of the transmission of data signals. The coming of Cat 6 does not signify that the previous standard is outdated, but rather Cat 5e is still employed in many LANs. However, to have a network with a high-data transmission speed, Cat 6 is highly recommended. Furthermore, UTP category 6 is backward compatible, which means that even having old-fashioned devices or a network being installed using previous-generation cable categories, Cat 6 is still completely suitable.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Such cables are commonly connected to devices such as computers, switches, and&nbsp; routers by means of RJ-45 connector at the end of each cable. The UTP wires is inserted into the connector in a specific order. The different colors of the eight wires are there to help putting each wire in its proper place. Such wires order within UTP is referred to as <b>pinout</b>. Importantly, the order of colors, or pinout, depends on which device is to be used. For example, connecting a computer to a router requires&nbsp; a certain order, whereas linking a computer to a switch needs a different wires order. In case the wires are put into the pinouts in an incorrect way, no signals will be transmitted on the cable and thus no connection will be established between sender and receiver. The telecommunication industry that is responsible for putting such rules is <b>TIA/EIA</b> (<span class="st"><span class="st">Telecommunications Industries Association/</span>Electronic Industries Association) </span>, which defined the order of the wires in the pinouts as <b>568A</b> and <b>568B</b> as standards.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">What follows is a set of instructions of how to do cabling in order to connect different devices. It is important to mention that there are three ways of ordering wires in the pinouts. Such ways of arranging the wires results in naming three types of cable, which are <b>Straight-through cable</b>,<b> Crossover cable</b>, and<b> Rollover cable</b>.</div><br /><div style="text-align: justify;">The aforementioned types of cable are used with specific devices, that is, to connect a given device to another, you should be able to identify which cabling type to use. To figure out all that, see the following figure.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-U1NibagtLoY/WVJGQqykILI/AAAAAAAACZc/cIHy4gwpjxUzUNfQ6hTPdfyV2AlJgd6IgCEwYBhgL/s1600/Straight-forward-vs-cross-over.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="435" data-original-width="700" height="396" src="https://4.bp.blogspot.com/-U1NibagtLoY/WVJGQqykILI/AAAAAAAACZc/cIHy4gwpjxUzUNfQ6hTPdfyV2AlJgd6IgCEwYBhgL/s640/Straight-forward-vs-cross-over.png" width="640" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-Sranufp4vp0/WVJR52IKcsI/AAAAAAAACaM/_p1MUfhggLk0cpmqGz0zSFiy55kR9RhXgCLcBGAs/s1600/type%2Bof%2Bcable-straight-through-crossover.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="385" data-original-width="497" height="247" src="https://2.bp.blogspot.com/-Sranufp4vp0/WVJR52IKcsI/AAAAAAAACaM/_p1MUfhggLk0cpmqGz0zSFiy55kR9RhXgCLcBGAs/s320/type%2Bof%2Bcable-straight-through-crossover.png" width="320" /></a></div><br /><div style="text-align: justify;">The above figure clarifies the way devices should be connected, or rather the types of cable that should be used.&nbsp; As you can see, to connect either a computer or a router to either a hub or a switch, we need to use straight-through. But if we want to connect either a computer or a router to another a computer or a router, we should use cross over.&nbsp; In the same way, if we wish to link either a hub or a switch to another a hub or a switch, we are required to use crossover. Significantly, rollover cable is not included on the grounds that it is Cisco-proprietary, that is to say, it is used only to connect Cisco devices with each other. It is utilized in connecting a machine with a serial port to a device with console port. Take a look at the following figure to know how rollover cable looks like.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-MEwWA8uCxv0/WVJI8P2OapI/AAAAAAAACZo/gt1-JAXX-SUYfJiAaZEmZX61W-7MpRD9gCLcBGAs/s1600/Rollover%2Bcable.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="387" data-original-width="626" height="394" src="https://1.bp.blogspot.com/-MEwWA8uCxv0/WVJI8P2OapI/AAAAAAAACZo/gt1-JAXX-SUYfJiAaZEmZX61W-7MpRD9gCLcBGAs/s640/Rollover%2Bcable.png" width="640" /></a></div><br /><div style="text-align: justify;">So far we covered what types of cable we need to use to connect different devices, but what is more important is to recognize how the wires in the pinouts of straight-through and crossover cables are placed. The tools that you need in order to get a cable done are Crimping tool, connectors, and a testing device so as to test whether the cable is well done or not. This figure shows the tools needed.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-7DjdnT0cKz0/WVJL43peuxI/AAAAAAAACZ0/9_UXp9lE0JgSL52r3bvoAljUlvWB1InQwCLcBGAs/s1600/Crimpring-tool-testing-device-RJ45-connector.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="387" data-original-width="626" height="394" src="https://4.bp.blogspot.com/-7DjdnT0cKz0/WVJL43peuxI/AAAAAAAACZ0/9_UXp9lE0JgSL52r3bvoAljUlvWB1InQwCLcBGAs/s640/Crimpring-tool-testing-device-RJ45-connector.png" width="640" /></a></div><br /><div style="text-align: justify;">Once the tools are available, take the cable and the connector, and remove the end part of the outer jacket of the cable. (to get the right size removed, put the end of the cable onto the end pins of the connector to measure how much you you should remove, because removing larger size of the outer jacket than the size of the connector causes the connector to be inefficient in terms of cabling. See the following figure to know how a connector should be done).</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-lhC_I5eqGOI/WVJQgrFOtMI/AAAAAAAACaA/JhIcVCV5JKcxgXYXiIcQiLKYXvXtoNE8ACLcBGAs/s1600/RJ45-correct-efficient-vs--incorrect-crimpring.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="387" data-original-width="626" height="246" src="https://3.bp.blogspot.com/-lhC_I5eqGOI/WVJQgrFOtMI/AAAAAAAACaA/JhIcVCV5JKcxgXYXiIcQiLKYXvXtoNE8ACLcBGAs/s400/RJ45-correct-efficient-vs--incorrect-crimpring.png" width="400" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-3hIp1ovJaCo/WVJSOVI7qVI/AAAAAAAACaQ/WSx_oSBGy6QvvCCUoCOWWBHdcv-mLqFHwCLcBGAs/s1600/RJ-45%2Bcrimping.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="461" data-original-width="502" height="365" src="https://2.bp.blogspot.com/-3hIp1ovJaCo/WVJSOVI7qVI/AAAAAAAACaQ/WSx_oSBGy6QvvCCUoCOWWBHdcv-mLqFHwCLcBGAs/s400/RJ-45%2Bcrimping.png" width="400" /></a></div><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" DefUnhideWhenUsed="true" DefSemiHidden="true" DefQFormat="false" DefPriority="99" LatentStyleCount="267"> <w:LsdException Locked="false" Priority="0" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Normal"/> <w:LsdException Locked="false" Priority="9" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="heading 1"/> <w:LsdException Locked="false" Priority="9" QFormat="true" Name="heading 2"/> <w:LsdException Locked="false" Priority="9" QFormat="true" Name="heading 3"/> <w:LsdException Locked="false" Priority="9" QFormat="true" Name="heading 4"/> <w:LsdException Locked="false" Priority="9" QFormat="true" Name="heading 5"/> <w:LsdException Locked="false" Priority="9" QFormat="true" Name="heading 6"/> <w:LsdException Locked="false" Priority="9" 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Accent 6"/> <w:LsdException Locked="false" Priority="68" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Grid 2 Accent 6"/> <w:LsdException Locked="false" Priority="69" SemiHidden="false" UnhideWhenUsed="false" Name="Medium Grid 3 Accent 6"/> <w:LsdException Locked="false" Priority="70" SemiHidden="false" UnhideWhenUsed="false" Name="Dark List Accent 6"/> <w:LsdException Locked="false" Priority="71" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Shading Accent 6"/> <w:LsdException Locked="false" Priority="72" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful List Accent 6"/> <w:LsdException Locked="false" Priority="73" SemiHidden="false" UnhideWhenUsed="false" Name="Colorful Grid Accent 6"/> <w:LsdException Locked="false" Priority="19" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Subtle Emphasis"/> <w:LsdException Locked="false" Priority="21" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Emphasis"/> <w:LsdException Locked="false" Priority="31" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Subtle Reference"/> <w:LsdException Locked="false" Priority="32" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Reference"/> <w:LsdException Locked="false" Priority="33" SemiHidden="false" UnhideWhenUsed="false" QFormat="true" Name="Book Title"/> <w:LsdException Locked="false" Priority="37" Name="Bibliography"/> <w:LsdException Locked="false" Priority="39" QFormat="true" Name="TOC Heading"/> </w:LatentStyles></xml><![endif]--><!--[if gte mso 10]><style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tableau Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} </style><![endif]--> <br /><div class="MsoNormal" style="text-align: justify;">Next, get the twisted wires away from each other and order them according the the cabling type you want. Taking straight-through as an example, the wires are ordered from right to left taking orange-white – orange – green-white – blue – blue-white – green – brown-white – brown. The following figure shows how wires in straight-through are ordered according to the colors.</div><div class="MsoNormal" style="text-align: justify;"><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-ZshFayUF-lE/WVJSa62butI/AAAAAAAACaU/mD45DWtJECsOynrCQSARduM51L-JplzBgCLcBGAs/s1600/straight-through%2Bcabling.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="409" data-original-width="774" height="338" src="https://3.bp.blogspot.com/-ZshFayUF-lE/WVJSa62butI/AAAAAAAACaU/mD45DWtJECsOynrCQSARduM51L-JplzBgCLcBGAs/s640/straight-through%2Bcabling.png" width="640" /></a></div></div><div class="MsoNormal" style="text-align: justify;">After arranging the wires, bring the connector holding the insertion lock tabs on the bottom, and insert the wires in a steady way. Then, take the crimping tool and press on the pins until each pin touches its wire counterpart. Finally, in order to test whether the cable works or not, you need a testing machine wherein both ends of the cable are plugged and if a set of points of light flash, it means the cable is perfectly done. See the following figure to get an idea.</div><div class="MsoNormal" style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-wNYZ-yQXq-Q/WVJTOP1ayLI/AAAAAAAACac/7xpYawDy3oEg3fAs-kKUf6P3SDZQPAQaQCLcBGAs/s1600/cable%2Btesting.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="244" data-original-width="384" height="253" src="https://4.bp.blogspot.com/-wNYZ-yQXq-Q/WVJTOP1ayLI/AAAAAAAACac/7xpYawDy3oEg3fAs-kKUf6P3SDZQPAQaQCLcBGAs/s400/cable%2Btesting.png" width="400" /></a></div><br /></div><div class="MsoNormal" style="text-align: justify;">Concerning the cabling method of crossover, it follows exactly the same process with the exception of four wires which has to be placed on different pins. It differs from the previous method in what regards the the position of the colors. Thus to get a crossover type of cable done, arrange the wire colors of the cable in the order shown in the following figure.<br /><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-m6gHDH-SeOQ/WVJTtafXUjI/AAAAAAAACak/bT2nPTK9pnUvDbRUz7eU9suy4w9vpl6AwCLcBGAs/s1600/crossover%2Bcabling.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="437" data-original-width="714" height="390" src="https://4.bp.blogspot.com/-m6gHDH-SeOQ/WVJTtafXUjI/AAAAAAAACak/bT2nPTK9pnUvDbRUz7eU9suy4w9vpl6AwCLcBGAs/s640/crossover%2Bcabling.png" width="640" /></a></div></div><div class="MsoNormal" style="text-align: justify;"><span style="font-size: large;"><b>Shielded twisted-pair (STP) cable</b></span><br /><br />Shielded twisted-pair is another copper cable type that is rarely used in today’s networks. It was especially used in IBM Token Ring network technology. It becomes less common in recent years because it has died out as Token Ring has been substituted by Ethernet technology.<br /><br />STP cable is more protective against outside interference than UTP thanks to the way the cable is made and the material used. It is designed to reduce noise caused by external devices that generate electromagnetic field. To fight against such interferece, the wires inside the cable are twisted together and shielded in a mesh. The following figure shows an example of STP cable.<br /><br /></div><div class="MsoNormal" style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-Amz5mGaldl8/WVJT3kPyWlI/AAAAAAAACao/6_1D32mxCrQmPcGtQ-UFpUGs0eJbcgUkwCLcBGAs/s1600/shielded%2Btwisted-pair.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="313" data-original-width="395" height="316" src="https://2.bp.blogspot.com/-Amz5mGaldl8/WVJT3kPyWlI/AAAAAAAACao/6_1D32mxCrQmPcGtQ-UFpUGs0eJbcgUkwCLcBGAs/s400/shielded%2Btwisted-pair.png" width="400" /></a></div><br /></div><div class="MsoNormal" style="text-align: justify;">STP cable is much more expensive than UTP cable on the grounds of its unique characteristics that make the cable safer and which shield it from outside noise. Notwithstanding the limited use of the cable at the present time, it is still used in areas where it is very difficult to avoid the interference. As such the cable is recommended in case there is no way but to use it for protection against external noise that causes unwanted signals.<br /><br /><div style="text-align: center;"><b>See the next lesson from here</b></div>[post_ad] </div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-83163784303884643172017-06-23T11:17:00.000-07:002017-06-24T11:19:28.354-07:00New News: Current Cisco Exams Dates<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: center;"><br /><div class="separator" style="clear: both; text-align: center;"><span style="font-size: large;"></span></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-u1BXjS7H0VM/WU1a2LGPwMI/AAAAAAAACY0/dwjOs-AvyikV8VkMEewtMS3qJMzXgrvQACEwYBhgL/s1600/Cisco-Current-Exams-Outlines.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://4.bp.blogspot.com/-u1BXjS7H0VM/WU1a2LGPwMI/AAAAAAAACY0/dwjOs-AvyikV8VkMEewtMS3qJMzXgrvQACEwYBhgL/s640/Cisco-Current-Exams-Outlines.png" width="640" /></a></div><br /><span style="font-size: large;">The first step to networking world is to pass one of the Cisco exams, for their importance as well as the fact of being recognized worldwide. As long as you entered this post, it means that you are interested in taking one the Cisco exams, including : </span></div><div class="separator" style="clear: both; text-align: center;"></div><br /><div style="text-align: justify;"><span style="font-size: large;"><b>Routing and Switching Certification Exams</b></span></div><div style="text-align: justify;"><span style="color: blue;"><span style="font-size: large;"><b>Cloud Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: red;"><span style="font-size: large;"><b>Data Center Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: lime;"><span style="font-size: large;"><b>Design Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: #0b5394;"><span style="font-size: large;"><b>Collaboration Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: #666666;"><span style="font-size: large;"><b>Cyber Ops Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: #660000;"><span style="font-size: large;"><b>Industrial Certification Exams </b></span></span></div><div style="text-align: justify;"><span style="color: orange;"><span style="font-size: large;"><b>Service Provider Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: #4c1130;"><span style="font-size: large;"><b>Wireless Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: #cc0000;"><span style="font-size: large;"><b>Field Technician Certification Exams</b></span></span></div><div style="text-align: justify;"><span style="color: #6aa84f;"><span style="font-size: large;"><b>Specialist Certification Exams</b></span></span></div><br /><span style="font-size: large;"><br /></span><br /><div style="text-align: center;"><span style="font-size: large;">Here is a list of the current exams, along with their dates. The exams are only in English and Japanese languages. See the exams dates below:</span></div><div style="text-align: center;"><br /></div>[post_ad]<span style="color: white; text-align: center;">&nbsp;</span><br /><div style="text-align: center;"><span style="color: white; font-size: xx-small; text-align: center;">Current&nbsp;</span><span style="font-size: xx-small;"><a href="http://www.cisco.com/c/en/us/training-events/training-certifications/exams/current-list.html" rel="nofollow" style="text-align: center;" target="_blank">Cisco</a><span style="color: white; text-align: center;">&nbsp;Exams Dates</span></span></div><div style="text-align: center;"><span style="color: white;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</span></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-27011561065600894142017-06-15T07:13:00.000-07:002017-06-27T06:33:24.912-07:0012: Cabling - copper cable (intro) part 1<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-H8tVG1y8d5w/WUKT1rmRjpI/AAAAAAAACNs/h7Cyiw3R9bYT4e1DTFndEnAtjUOO7VxgwCLcBGAs/s1600/cabling-RJ-45-fiber-optics.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1000" data-original-width="1600" height="400" src="https://2.bp.blogspot.com/-H8tVG1y8d5w/WUKT1rmRjpI/AAAAAAAACNs/h7Cyiw3R9bYT4e1DTFndEnAtjUOO7VxgwCLcBGAs/s640/cabling-RJ-45-fiber-optics.png" width="640" /></a></div><br />For data to be transmitted, devices must be connected by means of either cables, or wireless. Covering all kinds of cabling is beyond the scope of this lesson, for cabling is a broad and large field of study. There is not only one type of cables, but rather there are a plethora of cable types and standards. Copper cable,&nbsp; fiber optics, and coaxial cable are the major sort of cables through which data is transmitted nowadays. However, each of which has unique characteristics and special using settings. Cabling process including copper cabling, fiber optics cabling, and connectors used on them are all defined at the physical layer.<br /><br /><span style="font-size: large;"><b>Copper cable</b></span><br />[post_ad]<br />Copper cable is the most used medium for data transmission in LANs. This technology has so greatly developed that it becomes part and parcel of almost every designed network. It is used to link hosts to devices such as switches, routers, hubs, bridges etc.&nbsp; If a network installer to utilize copper in a given LAN network, several elements must be taken into consideration. The first element is the type of copper cabling. One should be careful when choosing the type of copper to be used, for a variety of copper cabling standards exist. Bandwidth of the communication should also be given due regard. A large network containing a vast array of devices must be devoted high bandwidth ; that occurs by choosing sophisticated technology. Furthermore, type of connectors cannot also be overemphasized. Each type of copper has special connectors that are peculiar to it ; as such selecting the appropriate connectors is a step of paramount importance.<br /><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-hNj3QXt0FUM/WUKVpQHryEI/AAAAAAAACNw/YiGn4j5viJo-SmlZfDWcYZ8bqBymofkuwCLcBGAs/s1600/copper%2Bcables.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1000" data-original-width="1600" height="400" src="https://2.bp.blogspot.com/-hNj3QXt0FUM/WUKVpQHryEI/AAAAAAAACNw/YiGn4j5viJo-SmlZfDWcYZ8bqBymofkuwCLcBGAs/s640/copper%2Bcables.png" width="640" /></a></div><br />Significantly, the network installer must be aware of the pinout and color codes of each type of media connection. For example, the arrangement of colors within a connector for connecting a computer to a router is not the same order used to link a computer to a switch ; nonetheless, the process has become much easier with the recent manufactured devices. The final thing that the network installer should pay regard to is the maximum distance of media.&nbsp; Long distances need different types of copper ; however, in distances larger than 100 meters other types cabling, rather than copper, is opted for.<br /><br />Thus far copper is the most pervasive media in use because of many advantages. Nevertheless, copper has also some drawbacks or limitations. Because of the fact that it conducts electrical signals and that data makes its way along the cable as small low pulses of voltage, thus data signals can be easily distorted by being subject to outside interference and signal attenuation. This latter implies that a signal loses energy as it travels long distances. Such outside interference or noise affects the timing and voltage values and consequently corrupts data signals. There are many sources of noise such as electric motors, signals of other devices or cables, radio waves to name but a few.<br /><br />Notwithstanding all such outside noise sources that badly influence data signals in copper, this medium has evolved in such a way that data can now be said to travel along the cable safely with less effects of interference. Enhancing copper cabling is not the merely solution to keep the noise away from it, but network installers or architects should pay enough heed to the area where the cables are put. This means that the cables should be located far from any systems that generate electromagnetic interference.<br /><br />After introducing copper as a type of cabling system, it is time to provide the available sub-types within it with a view to make the reader closer to copper. The most common types of copper cable are Unshielded Twisted-Pair (UTP) cabling, Shielded Twisted-Pair (STP) cabling, and coaxial cabling.<br /><br /><div style="text-align: center;"><b>See the next lesson from here </b></div>[post_ad] </div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-71303694133989179412017-05-30T12:02:00.000-07:002017-06-14T10:38:07.290-07:0011: Physical layer - what is bandwidth, throughput, and goodput part 3<div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-9FscUaHvZH0/WS3A4CEmdII/AAAAAAAACMg/xWg4qie8G5QrKzFfUKOmHTMhMl8HKCLZgCLcB/s1600/bandwidth%252C%2Bthroughput%252C%2Bgoodput.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://1.bp.blogspot.com/-9FscUaHvZH0/WS3A4CEmdII/AAAAAAAACMg/xWg4qie8G5QrKzFfUKOmHTMhMl8HKCLZgCLcB/s640/bandwidth%252C%2Bthroughput%252C%2Bgoodput.png" width="640" /></a></div><br /><div style="text-align: justify;">Data is carried on media at a different speed depending on the technology used. So to analyze the speed of the transmission of data on a given medium, we need to rely on three ways. Bandwidth, throughput, and goodput.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">These three variations have different functions in terms of measuring&nbsp; data transfer. Each of them measures an aspect of data transmission.&nbsp; Besides, all of which insist in the same standard that is bits per second.</div><br /><span style="font-size: large;"><b>Bandwidth</b></span><br /><br /><div style="text-align: justify;">To start with, bandwidth means the amount of data that can be carried in a given amount of time; or, in other words, the capacity of a medium to carry data in a specific period of time. As stated previously, data transfer is measured using bits per second (bps). Thanks to the technological development, bandwidth is now commonly referred to in kilobits per second and megabits per second, and in case using highly sophisticated media, bandwidth can reach gigabits per second and terabits per second. These speeds can be achieved relying on the physical&nbsp; characteristics of media and the signaling method being applied. Thus if one is to calculate the bandwidth of a given medium, the physical properties as well as the signaling method must be taken into consideration.</div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">To make things much clearer, it is of pivotal importance to provide an example of analogy. Suppose that the medium through which data frames to be transmitted is analogous to a tube and the bandwidth is an amount of water. </div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-EIOI3lvcuV8/WPEDCiwtWpI/AAAAAAAACL0/SIerQ5EOleUCJ9jGiN1prpNVvnSUXBIVgCLcB/s1600/bandwidth-example-analogy.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="424" src="https://2.bp.blogspot.com/-EIOI3lvcuV8/WPEDCiwtWpI/AAAAAAAACL0/SIerQ5EOleUCJ9jGiN1prpNVvnSUXBIVgCLcB/s640/bandwidth-example-analogy.png" width="640" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><br /><div style="text-align: justify;">As you can see in the above figure, the amount of water that can be passed through tube 1 to reach the end in one second&nbsp; is not the amount of water that tube 2 allows flowing towards to the end in one second. Tube 1 carries much more water than tube 2 in one second, because of the fact that tube 1 is broader and larger than tube 2 and thus resulting in a far great amount of water being accumulated at the end of the tube 1 than tube 2. From these differences wa can infer that the amount of data frames that are transmitted through a medium that is very sophisticated and works at high speed is considerably dissimilar from the volume of data frames that are transferred through an antiquated medium that operates at a low speed. Now it can be said that tube 1 allows more bandwidth than tube 2. Thus bandwidth depends largely on media used.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">The following units of bandwidth and their equivalence in bits may be useful in measurement.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-32PkEPgCEXY/WPEDZYPMOOI/AAAAAAAACL4/NsVtfE9TMDoA28Deh6tP0Mhd5u2FpEsLACLcB/s1600/bandwidth.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="163" src="https://2.bp.blogspot.com/-32PkEPgCEXY/WPEDZYPMOOI/AAAAAAAACL4/NsVtfE9TMDoA28Deh6tP0Mhd5u2FpEsLACLcB/s640/bandwidth.png" width="640" /></a></div><span style="font-size: large;"><b>Throughput</b></span><br /><br /><div style="text-align: justify;">The next term which is equally significant is throughput.&nbsp; It can be defined as the real or actual data transfer rate in a given amount of time. We said that bandwidth is the capacity of a medium for data transmisstion, however, this capacity is hardly attained in real data transfer because of a variety of factors such as interference, noise, and errors in data transmission. For this reason, when we talk about bandwidth, we are actually taking about a theoretical rate of speed which is not same when data frames are really transmitted, whereas when we refer to the speed rate of a given medium using a throughput value, we are actually utilizing the real value at which data frames are carried. This means that throughput is bandwidth minus interference and errors, and therefore bandwidth is theoretical and throughput is practical.</div><div style="text-align: justify;"><br />In addition, when designing a network, the designer must take into account all what can keep the network from attaining the real speed rate. In other words, throughput is to be taken into consideration rather than bandwidth when planning networks. In the same way as bandwidth, throughput is measured in bits per second.</div><div class="separator" style="clear: both; text-align: justify;"></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Significantly, throughput can also be influenced by many factors that might prevent it from attaining the expected rate of speed. The factors that may affect the throughput vary. The amount of traffic is one key factor. A medium being used by devices that use internet immensely&nbsp; results in reducing the throughput. Besides, the type of traffic may make inroads on throughput as well. For example, watching videos with high quality online is not like navigating a website such as facebook. The former case is more throughput-consuming than the latter. Another main factor that has a mammoth influence on throughput is the number of network machines being connected to the medium being measured. Logically, the throughput of a medium gets degraded if the number of devices increases. A very good example to consider is multiaccess topology using Ethernet technology when nodes compete media access. See the followinf figure.</div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-xglgEcJLS7Q/WPED5zKsAkI/AAAAAAAACL8/RuWmrlfaUFErB8eRFwDgEzeK8LEhoNI8gCLcB/s1600/Multiaccess%2BTopology.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="275" src="https://2.bp.blogspot.com/-xglgEcJLS7Q/WPED5zKsAkI/AAAAAAAACL8/RuWmrlfaUFErB8eRFwDgEzeK8LEhoNI8gCLcB/s640/Multiaccess%2BTopology.png" width="640" /></a></div><span style="font-size: large;"><b>Goodput</b></span><br /><br /><div style="text-align: justify;">The final crucial measuring component is goodput.&nbsp; It denotes&nbsp; the transfer rate of the actual usable data bits; or, to put it another way, goodput measures the final data that the user benefits from or use, for data such as a picture, text, or video does not travel on media alone, but rather there is another control information, which is generally considered as data, or what is referred to as overhead. Its purpose is to make sure that data is safe, undammaged, unrepeated, and to guide data up to the destination. Thus there is no need to include the overhead in goodput measuring as long as it is not actually used by the user. The scenario is that when data is generated by the user at the application layer, it passes by all of the lower layers, and each layer attaches its overhead information to the data. The following figure clarifies overhead encapsulation.</div><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-xhsP0ufjpjY/WPEENrARvwI/AAAAAAAACMA/njz1ToD_eeMNQiogBQI3frn5Xn3thtvYwCLcB/s1600/throughput%2Bvs%2Bgoodput.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="336" src="https://3.bp.blogspot.com/-xhsP0ufjpjY/WPEENrARvwI/AAAAAAAACMA/njz1ToD_eeMNQiogBQI3frn5Xn3thtvYwCLcB/s640/throughput%2Bvs%2Bgoodput.png" width="640" /></a></div><div style="text-align: justify;">By and large, it can be said that goodput is throughput minus overhead traffic. Such traffic can be there for establishing a session between two ends , acknowledgments, and data encapsulation. All of these processes consume a considerable amount of throughput. As such including overhead in the calculation of goodput is not useful.</div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">A rather simplified scenario comprising all of the three measuring components might remove ambiguities. For instance,&nbsp; A local area network has two devices connected to each other. One device sends a file to the other one, let it be a video. The bandwidth of the LAN network is 100 Mbps. But because of the fact that the devices share the media, the throughput between the devices is merely 60 Mbps. By removing the overhead from the actual data, which has been encapsulated throughout the layers,&nbsp; the real rate of the data received by the receiving device, goodput, is only 40 Mbps.</div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-64890973931574278732017-05-27T10:07:00.000-07:002017-05-28T10:03:39.238-07:0011: Physical layer - Encoding and signaling part 2<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><br /><div class="separator" style="clear: both; text-align: center;"><span style="font-size: large;"><b><a href="https://3.bp.blogspot.com/-dLDJVi5eYSM/WSmyAdqqAGI/AAAAAAAACMQ/uw6x1uu4aLIwWK3iuM5TbFay5hweWW3UQCLcB/s1600/encoding-and-signaling.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="389" data-original-width="626" height="396" src="https://3.bp.blogspot.com/-dLDJVi5eYSM/WSmyAdqqAGI/AAAAAAAACMQ/uw6x1uu4aLIwWK3iuM5TbFay5hweWW3UQCLcB/s640/encoding-and-signaling.png" width="640" /></a></b></span></div><br /><span style="font-size: large;"><b>&nbsp;Encoding and signaling</b></span></div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">Encoding&nbsp; and signaling are the main functions of layer one of the OSI reference model, physical layer. At the data-link layer, frames are in the form of bits (zeros and ones), but when they get down to the physical layer, they get turned into other formats that the physical layer understands ; in this case they are transformed into signals, because they need&nbsp; to be carried through cables and devices, which reside at the same layer, hence encoding and signaling. See the the following figure.</div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-Fqjksu9rS64/WMcRAY9-QUI/AAAAAAAACLQ/Lk1rOrl2LLgKW3T5v5zDGPVH1KMno33pACLcB/s1600/encoding%2Bvs%2Bsignaling.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="260" src="https://2.bp.blogspot.com/-Fqjksu9rS64/WMcRAY9-QUI/AAAAAAAACLQ/Lk1rOrl2LLgKW3T5v5zDGPVH1KMno33pACLcB/s640/encoding%2Bvs%2Bsignaling.png" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">In order for data to be recognized by both sender and receiver, it must be put in a specific order, or grouped, or encoded into patters. Devices must&nbsp; adhere to some rules when encoding data so that when it is received at the destination, it would be easily understandable by means of being subjected to the same rules, or decoding process. Thus, data is accumulated at the data-link layer as a frame, encoded into patterns recognized by layer 1 devices,&nbsp; travels as signals onto media (e.g. cables, wireless), then received by the layer 1 of the destination and decoded&nbsp; so as to be handed up to the upper layer as a frame again.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">In addition to grouping data bits into patterns, encoding has got another function which is control information. As you know, a cable, on which bits in the form of signals are transmitted, is busy with signals containing zeros and ones, and to distinguish between what bits are the actual traveled data and what bits are non-wanted noise is very difficult ; so a method to tell the difference is required. For that reason, control information is utilized. This information is in the form of zeros and ones that indicate where a frame start and where the frame ends. The following figure clarifies how frames are distinguished from other extra bits.</div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-6k2j0OaeHH0/WMcRM4Aj8dI/AAAAAAAACLU/-mD0grHjGi4AQHiekPLM3QvZRyuz4oYIwCLcB/s1600/the%2Bstart%2Band%2Bthe%2Bend%2Bof%2Bthe%2Bframe.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="252" src="https://4.bp.blogspot.com/-6k2j0OaeHH0/WMcRM4Aj8dI/AAAAAAAACLU/-mD0grHjGi4AQHiekPLM3QvZRyuz4oYIwCLcB/s640/the%2Bstart%2Band%2Bthe%2Bend%2Bof%2Bthe%2Bframe.png" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Therefore, frames are put in a string of binary bits, comprising the control information that informs where the actual data is located within a stream of bits, as well as acting as a means of guiding the bits up to the destination by virtue of signals, whose function is to carry the&nbsp; bits patterns. So signaling is another function of the physical layer.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Source machine and destination machine do the same thing in terms of encoding and signaling. When encoded and signaled frames get out the source machine heading towards the destination, this latter picks the frames in the form of signals and reverses the process. In other words, the destination apply the same mechanism to convert the patterns of physical energy into binary bits, then decoding the encoded bits to get the actual frame to be handed up to the upper layers.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><span style="font-size: large;"><b>Representing bits on media&nbsp;</b></span></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">The methods of representing binary digits on physical media vary and covering all of them is beyond the scop of this study ; However, providing at least two methods, which are Manchester encoding and nonreturn to zero (NRZ),&nbsp; to demonstrate how things are going on will suffice. These methods have their own distinctive ways of converting a pulse of energy into a defined amount of time referred to as a bit time.&nbsp; This latter means how much time a given Network Interface Card at the OSI model takes generate 1 bit of data and put it onto media in the form a signal. So the way binary bits&nbsp; are represented onto media&nbsp; as a signal indicates whether it is 0 or 1 at a time. This is achieved by virtue of three possible variations which are amplitude, frequency, and phase. Take a look at this figure to have an idea.</div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-m-XZA2Eu1Bw/WMcRW0l-1lI/AAAAAAAACLY/9ngwp7uD6uUSY3x9LCAIiLWQBk70JpQSwCLcB/s1600/signal%2Bmethods.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="200" src="https://4.bp.blogspot.com/-m-XZA2Eu1Bw/WMcRW0l-1lI/AAAAAAAACLY/9ngwp7uD6uUSY3x9LCAIiLWQBk70JpQSwCLcB/s640/signal%2Bmethods.png" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><b>Manchester encoding</b></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">This signaling method makes use of whether the amplitude is in a high or a low position.&nbsp; If a voltage (amplitude) drops from&nbsp; low to&nbsp; high within the bit time, it represents a 1 ; whereas, in case a voltage&nbsp; (amplitude) moves from&nbsp; high to&nbsp; low, it represents a 0. If a value is repeated such 1111 or 0000, it is represented by repeating the same movement of the amplitude. In addition, moving from one position to another (from high to low, or vice versa), happens at the edge of the time bit. The following figure shows how Manchester encoding occurs in a rather simplified way.</div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-hYgAkJaDabI/WMcRgTCRs7I/AAAAAAAACLc/6mVMtVm0fBUYA9M85g5DEb4OpVXdI66ZACLcB/s1600/manchester%2Bencoding.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="352" src="https://1.bp.blogspot.com/-hYgAkJaDabI/WMcRgTCRs7I/AAAAAAAACLc/6mVMtVm0fBUYA9M85g5DEb4OpVXdI66ZACLcB/s640/manchester%2Bencoding.png" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">This signaling method is not suitable for higher-speed links. It is rather fitted for lower-speed links such as 10Base-T Ethernet whose speed is 10 megabits per second.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><b>Nonreturn To Zero (NRZ)</b></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">NRZ stands for Nonreturn to Zero. It is another signaling method in which bits representation lies in the voltage level within a bit time. The level of the voltage can either be a 0 or a 1. More specifically,&nbsp; If the the level of the voltage is high, then the voltage represents 1. Contrariwise, if the level of the voltage is low, or rather remaining steady, it is in this case a 0. Consider the following figure.&nbsp;</div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-WJQ0qKrCpZ0/WMcRn1BjAaI/AAAAAAAACLg/pfMVR9KNNnAnfaZzJtaco_IgJ6OZh9K4QCLcB/s1600/NRZ%2Bencoding-nonreturn%2Bto%2Bzero.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="290" src="https://1.bp.blogspot.com/-WJQ0qKrCpZ0/WMcRn1BjAaI/AAAAAAAACLg/pfMVR9KNNnAnfaZzJtaco_IgJ6OZh9K4QCLcB/s640/NRZ%2Bencoding-nonreturn%2Bto%2Bzero.png" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">But this signaling methods has also some weaknesses which prevent it from being used in higher-speed links. It is not inherently a self-clocking signal. Simply put, a string of 0's or 1's in NRZ prevent the sender and the receiver clocks from being synchronized.[post_ad]</div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-80994158493500578452017-02-25T14:14:00.000-08:002017-02-26T08:13:06.156-08:0011: Physical layer - layer 1 of OSI model (intro) part 1<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-BeAz6IechVA/WLIAkdP13JI/AAAAAAAACEw/24ibDB_WrNMYNbT2G83kHcWXaJiCIp-tACLcB/s1600/physical--layer.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="392" src="https://1.bp.blogspot.com/-BeAz6IechVA/WLIAkdP13JI/AAAAAAAACEw/24ibDB_WrNMYNbT2G83kHcWXaJiCIp-tACLcB/s640/physical--layer.png" width="640" /></a></div><br /></div><div style="text-align: justify;">We eventually reach the final OSI model layer to explain, which is the Physical Layer ; the first layer in the model. Unlike the other upper layers, the physical layer deals directly with the real or physical data transmission on media, as its name implies. The role of this layer is to convert frames, which includes the control information of each layer, from bits format into signals which can be transmitted in the form of either voltage through copper cables, or light by means of fiber-optic cables, or radio waves (wirelessly) through the air.<br /><br /><div style="text-align: justify;">Data communication in networks is analogous to human communication. In human communication, when a person wishes to communicate an idea or convey it to someone else, he or she processes abstract thought into words, which are then encoded into a particular format, either spoken, written, or gestures and sent out through a medium, such as the air for spoken communication , letters for written communication, and light for gestures. On the part of the receiver, he or she interprets the received message, be it written or spoken, recognizes patterns in the message that denote words, and afterwards processes the meaning of the words into the original idea. Each of the mentioned media has unique ways of communicating ideas, so the same is true of networks communication. For example, Copper cables is different from fiber optics in terms of signaling.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">In networks communication terms, when data passes by all the upper layers and reaching the data-link layer in which it becomes a&nbsp; frame, it is passed down to the physical layer in the form of binary digits. Then, the binary digits are subjected to a process of encoding whereby bits are grouped in a certain way. Next, the bits are converted into signals, by means of the signaling process, to be transmitted through a medium until reaching the destination where the process is reversed; converting signals into binary digits to constitute the frame again. </div></div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">The process of data at the upper layers, from the application layer until&nbsp; the upper half of the data-link layer, is implemented in software, that is, there is no actual transmission of data, or rather no tangible dealing with media, whereas data from the lower half of the data-link layer up to the physical layer is done physically, or rather implemented in hardware ; that is to say, the physical layer puts all of the accumulated data onto media e.g. wireless or cables. See the following figure.<br /><br /></div><div style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-aAWlX2saHJs/WLHD5luySaI/AAAAAAAACEU/IPplHl0og90FJUJmDQpVZf1U_oMsNP8xwCLcB/s1600/Physical%2Blayer-implemented%2Bin%2Bhardware.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="210" src="https://4.bp.blogspot.com/-aAWlX2saHJs/WLHD5luySaI/AAAAAAAACEU/IPplHl0og90FJUJmDQpVZf1U_oMsNP8xwCLcB/s400/Physical%2Blayer-implemented%2Bin%2Bhardware.png" width="400" /></a></div><br /></div><div style="text-align: justify;">Furthermore, the upper layers,&nbsp; which are implemented in software, are the concern of software engineers and computer scientists who develop network applications, services and protocols. An example of such body of engineers and scientist is Internet Engineering Task Force (IETF), which is an organization comprising a large number of participants who voluntarily develop internet standards, such as protocol suite (TCP/IP) standards.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">By contrast, the lower layers including the second bottom part of the data-link layer and physical layer, which are implemented in hardware, are the specialization of electrical engineers who develop and promote network devices, electronic circuitry, and connectors. The following are some chief organizations :</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">- The American National Standards Institute (ANSI)</div><div style="text-align: justify;">- The International Telecommunication Union (ITU)</div><div style="text-align: justify;">- The International Organization for Standardization (ISO)</div><div style="text-align: justify;">- The Institute of Electrical and Electronics Engineers (IEEE)</div><div style="text-align: justify;">- The Electronics Industry Alliance/Telecommunications Industry Association (EIA/TIA)</div><div style="text-align: justify;">- National telecommunications authorities such as the Federal Communications</div><div style="text-align: justify;">Commission (FCC), the independent agency of the United States government</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><b>Role of the physical layer</b></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">The main role of the physical layer is taking data-link layer frames represented&nbsp; in binary digits and turning them into physical signals to be transmitted through media. This is done through the processes of <b>encoding</b> and <b>signaling </b>through <b>physical components</b>, which we shall cover in the next lesson.</div><div style="text-align: justify;">[post_ad]</div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-22021128565513429332017-02-24T08:18:00.000-08:002017-02-24T08:18:04.135-08:00How to track your car, laptop, wallet, animal, keys, or anything else using your phone and a tiny device - unbelievable !<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-sMvXF7Yz9lc/WLBauUT1W_I/AAAAAAAACEE/exoRWsLea6sHDMe_kB1XiLl5EI616qt7ACLcB/s1600/TrackR.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="392" src="https://3.bp.blogspot.com/-sMvXF7Yz9lc/WLBauUT1W_I/AAAAAAAACEE/exoRWsLea6sHDMe_kB1XiLl5EI616qt7ACLcB/s640/TrackR.png" width="640" /></a></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Have you ever been stolen from or lost your car in parking ? have you ever lost your wallet and you did not find it ? have you ever thought of tracking your stuffs ? it happens. In this article you will discover a very advanced way of keeping track of whatever thing you want using only your phone and a very small device. By virtue of this latter you can only by one click to locate your possessions in seconds.</div><br /><div style="text-align: justify;">All you need to do is just to attach the device, called TrackR, to the&nbsp; things that you want to track, then install a small application on your phone (<b><a href="https://play.google.com/store/apps/details?id=com.phonehalo.itemtracker" target="_blank">Android</a></b> or <b><a href="https://itunes.apple.com/us/app/item-trackr-find-your-wallet/id588363491?mt=8" target="_blank">Iphone</a></b>), afterwards tracking will be ready. These steps are very easy to do.&nbsp; After everthing is ready, you need merely to whip out your phone and open the application and&nbsp; the location of your stuffs will clearly appear on the screen.</div><br /><div style="text-align: justify;">With this device you will no longer lose your wallet, keys, laptop, bicycle, etc. For example, you can attach this tiny device to your laptop, and when it is stolen, or lost, you can by only one click to find it. It is especially useful when you are stolen something from and the device is already attached to it, the thief will be caught red-handed.</div><br /><div style="text-align: justify;">This device is much better than the GPS services, which are very expensive, and which oblige you to monthly pay for the service. In contrast, TrackR is very cheap and once you buy, you will no longer pay for it. It will work forever. For instance, if you have TrackR, you need just to hide it somewhere in the car such as the compartment or under the car's floor mat, and when you wish to keep tabs on it, all you need to do is bring your phone out and the car's place will immediately be shown</div><br /><span style="font-size: large;"><span style="color: blue;"><b>How much does it cost ?</b></span></span><br /><br /><div style="text-align: justify;">No worries this device is not expensive, it is only $29 unlike GPS for which you have to pay a bundle to get </div><div style="text-align: justify;">the service. the price that you are going to pay is for peace of mind, for you will no more complain about losing your stuff.</div><br /><span style="color: blue;"><span style="font-size: large;"><b>Where can I buy this device - TrackR ?</b></span></span><br /><br />You can buy it directly from the <b><a href="https://buy.thetrackr.com/?ref_code=EdlXi" target="_blank">company's website</a></b> <br />[post_ad]<br /><span style="color: blue;"><span style="font-size: large;"><b>How much time it needs to be delivered ?</b></span></span><br /><br />This company ships worldwide and you'll receive your TrackR device within a week. Up to now, there are over 4.5 million devices shipped<br /><br /><div style="text-align: center;"><span style="font-size: large;">Watch this video to know how TrackR device works:</span></div><br /><br /><div style="height: 0; padding-bottom: 56.25%; position: relative;"><iframe allowfullscreen="" frameborder="0" height="360" src="https://www.youtube.com/embed/O2hbQjNLibI?ecver=2" style="height: 100%; left: 0; position: absolute; width: 100%;" width="640"></iframe></div><br /><br /><div style="text-align: center;"><span style="font-size: large;">To know about customers feedback, watch this video</span></div><br /><br /><div style="height: 0; padding-bottom: 56.25%; position: relative;"><iframe allowfullscreen="" frameborder="0" height="360" src="https://www.youtube.com/embed/6FU9jKRnhdU?ecver=2" style="height: 100%; left: 0; position: absolute; width: 100%;" width="640"></iframe></div><br /><br /><div style="text-align: center;"><span style="font-size: large;">I hope you have enjoyed this article. If so, do not forget to share it with your friends for the purpose of spreading knowledge.</span></div><div style="text-align: center;"><span style="font-size: large;"><span style="font-size: small;">[post_ad] </span></span></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-41540844583977694062017-02-19T14:00:00.002-08:002017-02-19T14:01:23.668-08:0010: Ethernet - IEEE 802.3 LLC frame & IEEE 802.3 SNAP frame part 16<div dir="ltr" style="text-align: left;" trbidi="on"><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w:HyphenationZone>21</w:HyphenationZone> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:DoNotPromoteQF/> <w:LidThemeOther>FR</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>AR-SA</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> 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table.MsoNormalTable {mso-style-name:"Tableau Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} </style><![endif]--> <br /><div class="MsoNormal" style="text-align: justify;"><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-K7UNjd9CRWE/WKoTwottuOI/AAAAAAAACDY/XGxEPPA1ZXEIUSOa-CRtpnMST6dD5-TuACLcB/s1600/IEEE%2B802.3%2BLLC%2Bframe%2B-%2BIEEE%2B802.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="424" src="https://4.bp.blogspot.com/-K7UNjd9CRWE/WKoTwottuOI/AAAAAAAACDY/XGxEPPA1ZXEIUSOa-CRtpnMST6dD5-TuACLcB/s640/IEEE%2B802.3%2BLLC%2Bframe%2B-%2BIEEE%2B802.png" width="640" /></a></div><br /></div><div class="MsoNormal" style="text-align: center;"><span style="font-size: x-large;"><b><span style="color: red;">IEEE 802.3 LLC frame</span> &amp; <span style="color: blue;">IEEE 802.3 SNAP frame</span></b></span></div><div class="MsoNormal" style="text-align: center;"><br /></div><div class="MsoNormal" style="text-align: justify;"><span style="font-size: large;"><b>IEEE 802.3 LLC&nbsp; (Logical Link Control) frame:</b></span><br /><br />By understanding and absorbing the ingredients of Ethernet II (DIX) frame, you do not need much effort to grasp what is contained in IEEE 802.3 (LLC) frame. <span style="mso-spacerun: yes;">&nbsp;</span>It is just a repetition of the fields except for three fields which pertain to IEEE 802.3 (LLC) frame. This Ethernet frame is currently not used except for <span style="mso-spacerun: yes;">&nbsp;</span>large corporate NetWare installations, which is an <span style="mso-spacerun: yes;">&nbsp;</span>obsolete computer network operating system. The fields that are peculiar to this frame format are <span style="mso-spacerun: yes;">&nbsp;</span>DSAP, SSAP, and Control fields. The following figure shows the structure of the frame.</div><div class="MsoNormal" style="text-align: justify;">[post_ad]</div><div class="MsoNormal" style="text-align: justify;"><span style="color: red;"><b>Note:</b></span> IEEE 802.3 LLC frame and IEEE 802.3 SNAP frame are rarely if not at all used in today's networks; instead, DIX Ethernet is the dominant one which is widely relied on in data transmission over networks, that is, the latter frame supersede the former ones.</div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-dT1lUoCChxg/WKnjcBrwJQI/AAAAAAAACCw/e2EJntlcY7wA7ITfHu6idzxNWtFPd0zmQCLcB/s1600/ETHERNET%2B802.3%2BFRAME.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="190" src="https://1.bp.blogspot.com/-dT1lUoCChxg/WKnjcBrwJQI/AAAAAAAACCw/e2EJntlcY7wA7ITfHu6idzxNWtFPd0zmQCLcB/s640/ETHERNET%2B802.3%2BFRAME.png" width="640" /></a></div><div class="MsoNormal" style="text-align: justify;">As shown in the figure, there are three new fields in 802.3 frame. There is no need to explain the the other fields. <br /><br /><b>SSAP (Source Service Access Point) :</b> is an 8-bit long field. It has the same function as Ethertype. It is used to distinguish between data transmitted on the same station; or in other words, to determine whether the data being transmitted is IPv4, or IPv6, or ARP request, or 802.1Q tagged frame etc. ; for each type of data is assigned a value through which data is identified.&nbsp; Here are some of these values&nbsp; 0x0800 means IPv4,&nbsp; 0x8100 means 802.1Q tagged frame, 0x0806 means ARP, and 0x86DD means IPv6. Thus, The SSAP indicates from which service the LLC data unit was sent. To put it another way, SSAP represents the logical address of the network layer entity through which the message is carried, and which created the message, or rather the&nbsp; network layer protocol that is sending. For example, a message might be carried by ipv4 ; so it can be said that IPv4 protocol type is the SSAP, which, for easy identification, puts its value 0x0800 in SSAP field. <br /><br /><b>DSAP (Destination Service Access Point) : </b>is also an 8-bit long field. This field functions as SSAP, but it contains the the value of the protocol to which data is addressed. SSAP and DSAP values must be the same because the protocol through which a message is generated in the source machine should be the same one the is going to receive the message in the destination machine. For example, a message sent by IPv6 network layer protocol must be received by IPv6 network layer protocol of the destination machine ; so both SSAP and DSAP fields must comprise IPv6 value which is 0x86DD. By and large, DSAP represents the logical addresses of the network layer entity intended to receive the message, or rather the network layer protocol that is receiving.<br /><b>Control :&nbsp;</b> is an 8-bit long field. This field indicates whether the communication is connection-less or connection-oriented (TCP or UDP protocols), which is usually performed by the upper layers (transport layer). <br /><br /><span style="font-size: large;"><b>IEEE 802.3 SNAP (Subnetwork Access Protocol) frame: </b></span><br /><br />This frame has emerged because of the fact that the LLC header of IEEE 802.3 LLC frame, which contains SSAP, DSAP, and Control fields, is too small to accommodate a large number of protocols. Thus, due to the short size of SSAP DSAP fields in the header that are unable to address all the layer three protocols or services, a need for another frame type, or rather the extention of IEEE 802.3 LLC frame was highly required. As a result, IEEE 802.3 SNAP frame was the one to have been created to solve the problem.&nbsp;</div><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-ptdJW3w-xyE/WKnkI9tKZfI/AAAAAAAACC4/wnGWT1gao3ATKCeUG9WsDbm4GH5ZEagGwCLcB/s1600/IEEE%2B802.3%2BSNAP%2BFRAME.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="150" src="https://4.bp.blogspot.com/-ptdJW3w-xyE/WKnkI9tKZfI/AAAAAAAACC4/wnGWT1gao3ATKCeUG9WsDbm4GH5ZEagGwCLcB/s640/IEEE%2B802.3%2BSNAP%2BFRAME.png" width="640" /></a></div><div class="MsoNormal" style="text-align: justify;">As the name implies, this frame type has added a new header called SNAP, whose size is 5 bytes (40 bits)&nbsp; that&nbsp; comprises&nbsp; OUI and ID fields. SNAP header comes into play when both source and destination (SSAP and DSAP) are set to the value 0xAA, and the control field is set to 0x03. In other words, if the SSAP and DSAP in LLC header are set to 0xAA and the control field is set to 0x03, then the SNAP service is requested, and as a result the SNAP encapsulation will occur.<br /><br /><b>OUI (Organizationally Unique Identifier) and ID fields :</b> is a 3-byte field that SNAP frame encompasses. If this field is assigned 000000 (hexadecimal), the ID is the Ethernet type (EtherType)&nbsp; field value for the protocol running on top of SNAP. But if the OUI field is an identifier of a specific organization, the ID field is a value allocated to a protocol assigned by that organization. For example, OUI is an advantage to vendors because they can create their own types to use, such as Cisco company, which has protocols that are peculiar to it and thus encapsulated with an ID value specific to the organization.<br />[post_ad]<br />A network might use different Ethernet frames. So how one can tell what frame is used in a given transmission !. The answer is found in the Length/type field. Notwithstanding The length field is used to indicate how many bytes of data are following this field before the FCS field, It can also be utilized to draw a distinction between DIX frame and 802.3 frame. If the field's value is greater than or equal to 1536, the frame must be an Ethernet v2 frame, with that field being a type field. If it's less than or equal to 1500, it must be an IEEE 802.3 frame, with that field being a length field.<br /><br /></div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-34655057695745545902017-02-10T15:21:00.000-08:002017-02-11T07:07:06.564-08:00Cisco's certification exams costs in 2017- CCENT, CCNA, CCNP, CCIE, and CCAr<div dir="ltr" style="text-align: left;" trbidi="on"><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-yTb7-H0tKIw/WJ5KVMKPgZI/AAAAAAAACB0/eNrOw5CbvlciO6eovggPC4T_JUOP5l1fQCLcB/s1600/cisco%2527s%2Bcertifications%2Bexams%2Bcosts.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="398" src="https://3.bp.blogspot.com/-yTb7-H0tKIw/WJ5KVMKPgZI/AAAAAAAACB0/eNrOw5CbvlciO6eovggPC4T_JUOP5l1fQCLcB/s640/cisco%2527s%2Bcertifications%2Bexams%2Bcosts.png" width="640" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><br /><div style="text-align: justify;"><span style="font-size: large;">Cisco's certification exams differ insisting in the level (type of certification), scope, and the length of the exam. Given the fact that Cisco exams costs are not stable, changing over time, and even varying from one country to another, they do not, however, change immensely.</span></div><div style="text-align: justify;"><span style="font-size: large;"><br /></span></div><div style="text-align: justify;"><span style="font-size: large;">The following are the exams' costs, which are adopted from Cisco website, depending on the level:</span></div><br /><span style="font-size: large;"><b><span style="color: red;">Entry : $125 - $165</span></b></span><br /><span style="font-size: large;"><b><br /><span style="color: blue;">Associate : $165 - $325 &nbsp;&nbsp;&nbsp; </span></b></span><br /><span style="font-size: large;"><b><br /><span style="color: purple;">Professional :&nbsp; $300 &nbsp;&nbsp;&nbsp; </span></b></span><br /><span style="font-size: large;"><b><br /><span style="color: lime;">Expert : $450 &nbsp; &nbsp;&nbsp;&nbsp; </span></b></span><br /><span style="font-size: large;"><b><br /><span style="color: #660000;">Specialist : $250 - $300</span></b></span><br /><br /><div style="text-align: justify;"><span style="font-size: large;">To get the exact price for the exam that you are a candidate for, please register online at <a href="http://www.pearsonvue.com/cisco/" target="_blank">Pearson VUE</a>&nbsp;</span></div>[post_ad]<br /><span style="font-size: x-large;"><b>Mobile CCIE Labs locations:</b></span><br /><br /><div style="text-align: justify;"><span style="font-size: large;">These are CCIE lab locations, taken from Cisco website:</span></div><span style="font-size: large;"><span style="font-size: small;"><b><br /></b></span></span><br /><table border="0" class="jiveNoBorder"><tbody><tr><td style="background-color: lightgrey; border: 0px solid black;" width="23%"><span style="font-size: large;"><span style="font-size: small;"><b>Lab Locations</b></span></span></td><td style="background-color: lightgrey; border: 0px solid black;" width="13%"><b>2017 Dates</b></td><td style="background-color: lightgrey; border: 0px solid black;" width="6%"><b>Status</b></td><td style="background-color: lightgrey; border: 0px solid black; text-align: center;"><b>Lab</b></td></tr><tr><td style="border: 0px solid black;">Toronto, Canada</td><td style="border: 0px solid black;">Jan 11 - 13</td><td style="border: 0px solid black; text-align: center;">A</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Singapore, Singapore</td><td style="border: 0px solid black;">Jan 18 - 20</td><td style="border: 0px solid black; text-align: center;">A</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Mexico City, Mexico</td><td style="border: 0px solid black;">Jan 25 - 27</td><td style="border: 0px solid black; text-align: center;">A</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Bogota, Colombia</td><td style="border: 0px solid black;">Feb 15 - 17</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Istanbul, Turkey</td><td style="border: 0px solid black;">Feb 15 - 17</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Jakarta, Indonesia</td><td style="border: 0px solid black;">Feb 22 - 24</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Montreal, Canada</td><td style="border: 0px solid black;">Mar 1 - 3</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Johannesburg, South Africa</td><td style="border: 0px solid black;">Mar 8 - 10</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Singapore, Singapore</td><td style="border: 0px solid black;">Mar 15 - 17</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Rio de Janeiro, Brazil</td><td style="border: 0px solid black;">Mar 22 - 24</td><td style="border: 0px solid black; text-align: center;">C</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Feltham, United Kingdom</td><td style="border: 0px solid black;">Mar 29 - 31</td><td style="border: 0px solid black; text-align: center;">A</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Toronto, Canada</td><td style="border: 0px solid black;">Apr 5 - 7</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Wuhan, P.R.China</td><td style="border: 0px solid black;">Apr 12 - 14</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Mexico City, Mexico</td><td style="border: 0px solid black;">Apr 26 - 28</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Singapore, Singapore</td><td style="border: 0px solid black;">May 17 - 19</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Rio de Janeiro, Brazil</td><td style="border: 0px solid black;">Jun 7 - 9</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Feltham, United Kingdom</td><td style="border: 0px solid black;">Jun 21 - 23</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Johannesburg, South Africa</td><td style="border: 0px solid black;">Jun 28 - 30</td><td style="border: 0px solid black; text-align: center;">R</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Shanghai, PR China</td><td style="border: 0px solid black;">Jul 19 - 21</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Moscow, Russia</td><td style="border: 0px solid black;">Jul 19 - 21</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Mexico City, Mexico</td><td style="border: 0px solid black;">Jul 26 - 28</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Toronto, Canada</td><td style="border: 0px solid black;">Aug 2 - 4</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Sao Paulo, Brazil</td><td style="border: 0px solid black;">Aug 9 - 11</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Johannesburg, South Africa</td><td style="border: 0px solid black;">Aug 16 - 18</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Singapore, Singapore</td><td style="border: 0px solid black;">Sep 6 - 8</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Mexico City, Mexico</td><td style="border: 0px solid black;">Oct 4 - 6</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Chengdu, PR China</td><td style="border: 0px solid black;">Oct 18 - 20</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Johannesburg, South Africa</td><td style="border: 0px solid black;">Nov 22 - 24</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Sao Paulo, Brazil</td><td style="border: 0px solid black;">Nov 29 - Dec 1</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Moscow, Russia</td><td style="border: 0px solid black;">Dec 6 - 8</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr><tr><td style="border: 0px solid black;">Singapore, Singapore</td><td style="border: 0px solid black;">Dec 6 - 8</td><td style="border: 0px solid black; text-align: center;">N</td><td style="border: 0px solid black;">Routing &amp; Switching, Security, Service Provider, Data Center, Wireless</td></tr></tbody></table><br /><br /><div style="text-align: justify;"><span style="font-size: large;"><span style="color: red;"><b>Note:</b></span> Candidates can register online at Pearson VUE for all exams apart from CCIE Lab exams, for they are supposed to pay directly to the authorized test delivery partner, <a href="http://www.pearsonvue.com/cisco/" target="_blank">Pearson VUE</a>.<b><br /></b></span></div><br /><span style="font-size: large;">CCIE lab exam registerations are done by loggining to the <a href="https://sso.cisco.com/autho/forms/CDClogin.html" target="_blank">CCIE</a> <a href="https://sso.cisco.com/autho/forms/CDClogin.html" target="_blank">Lab Scheduling tool.</a></span><br /><br /><div style="text-align: justify;"><span style="font-size: large;">The following links are for Experts and Architects to get more information about Lab and Practical exam information:</span></div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;"><a href="https://learningnetwork.cisco.com/community/certifications/ccie_routing_switching/lab_exam_v5" target="_blank"><span style="font-size: large;">CCIE Lab Exams</span></a></div><div style="text-align: justify;"><a href="https://learningnetwork.cisco.com/community/certifications/ccde/practical_exam/practice" target="_blank"><span style="font-size: large;">CCDE Practical Exams</span></a></div><div style="text-align: justify;"><span style="font-size: large;"><a href="https://learningnetwork.cisco.com/community/certifications/cisco_certified_architect/board_exam" target="_blank">CCAr </a></span></div><br /><span style="font-size: large;"><span style="color: blue;">To keep in touch with any news concerning prices, dates, changes, etc., please click like on our facebook page.</span></span><br /><span style="font-size: large;">&nbsp;</span><b><span style="font-size: large;"> </span></b></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-18710021881791431012017-02-08T15:17:00.001-08:002017-02-08T15:17:48.545-08:0010: Ethernet - Ethernet II (version 2, or DIX) frame - Preamble and SFD (Start Frame Delimiter) part 15<div dir="ltr" style="text-align: left;" trbidi="on"><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><b><a href="https://2.bp.blogspot.com/-CfsBeTmxbsw/WJumuKV6MdI/AAAAAAAACBY/UlXfl9h2IVo76ZTo1zaenS1_dj5CBLTlQCLcB/s1600/Ethernet%2BII%2B%2528version%2B2%252C%2Bor%2BDIX%2529%2Bframe%2B-%2BPreamble%2Band%2BSFD%2B%2528Start%2BFrame%2BDelimiter%2529.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="424" src="https://2.bp.blogspot.com/-CfsBeTmxbsw/WJumuKV6MdI/AAAAAAAACBY/UlXfl9h2IVo76ZTo1zaenS1_dj5CBLTlQCLcB/s640/Ethernet%2BII%2B%2528version%2B2%252C%2Bor%2BDIX%2529%2Bframe%2B-%2BPreamble%2Band%2BSFD%2B%2528Start%2BFrame%2BDelimiter%2529.png" width="640" /></a></b></div><br /><div style="text-align: justify;"><b>Preamble and SFD (Start Frame Delimiter):</b></div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">Preamble and SFD are also part of the frame but they are not considered to be fields that accompany the frame up to the receiver (that is why I let them the last things to explain). They function only at the very beginning, or rather before the actual transmission of data. They both act as a means that&nbsp; notifies the receiver to be ready because data frame in going to be transmitted. For that reason, it is positioned at the beginning of the frame as seen in this figure.</div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-1-6IG7AG-H0/WJugX9DAG_I/AAAAAAAACA4/nPlSU4j0eSEnIPy2u4MWx4mjnhJLTq5TACLcB/s1600/frame-preamble%252BSFD.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="160" src="https://2.bp.blogspot.com/-1-6IG7AG-H0/WJugX9DAG_I/AAAAAAAACA4/nPlSU4j0eSEnIPy2u4MWx4mjnhJLTq5TACLcB/s640/frame-preamble%252BSFD.png" width="640" /></a></div><br /><div style="text-align: justify;">The function of preamble is to put a set of zeroes and ones on the network so that the receiver figures out that a sender is on the threshold of initiating a data transmission. Consider this figure.</div><div style="text-align: justify;"><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-ZfC5E1DaUP8/WJugtUJ40TI/AAAAAAAACA8/LhL8SfxGGdkPFwigp4EkrAoOs-3f_WvsQCLcB/s1600/preamble-sfd.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="347" src="https://3.bp.blogspot.com/-ZfC5E1DaUP8/WJugtUJ40TI/AAAAAAAACA8/LhL8SfxGGdkPFwigp4EkrAoOs-3f_WvsQCLcB/s640/preamble-sfd.png" width="640" /></a></div><div style="text-align: justify;">The ones and zeroes that appear on the picture are the preamble per se. They are used to synchronize the clocks of devices, for their clocks might be in different positions. For example, suppose that PC-1 in the above figure&nbsp; wants to send a set of data to PC-4. The first thing that the sender will do, in order to establish a connection, is to send 56 bits 10101010 10101010 10101010 10101010 10101010 10101010 1010101 to make the receiver aware of the data that is going to be sent. When the clocks of the sender and receiver are synchronized, then the role of preamble is finished. To mark the end of the preamble and the start of the actual frame, the sender sends other 8 bits 10101011 different from previous ones. Take a look at this example.</div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-61GiHCYhjtM/WJuhFcz1FBI/AAAAAAAACBE/JaiDw6v4liQFHgO94E9Dn2-rLKa0jlrygCLcB/s1600/peamble-sfd-frame.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="209" src="https://1.bp.blogspot.com/-61GiHCYhjtM/WJuhFcz1FBI/AAAAAAAACBE/JaiDw6v4liQFHgO94E9Dn2-rLKa0jlrygCLcB/s640/peamble-sfd-frame.png" width="640" /></a></div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">As you see in the figure, the clocks are synchronized thanks to the preamble ; and the the last bit of the preamble and the first bit of the actual frame is broken by SFD ( Start Frame Delimiter). In a nutshell, the preamble&nbsp; consists of a group of bits put on the network&nbsp; to allow devices on the network to easily synchronize their receiver clocks. Af for the SFD, it is used to mark the end of the preamble and indicates the beginning of the frame. </div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0tag:blogger.com,1999:blog-7883534603015733225.post-63577709315232593602017-02-07T11:13:00.000-08:002017-02-08T14:55:13.093-08:0010: Ethernet - How to calculate CRC (Cyclic Redundancy Check) ? part 14<div dir="ltr" style="text-align: left;" trbidi="on"><br /><div class="separator" style="clear: both; text-align: center;"><b><a href="https://1.bp.blogspot.com/-guXeTztqb1A/WJocFEARhFI/AAAAAAAACAo/78kEuCc9JqEdhW021zuyYMPXDF8hT0aTACLcB/s1600/how%2Bto%2Bcalculate%2BCRC2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="360" src="https://1.bp.blogspot.com/-guXeTztqb1A/WJocFEARhFI/AAAAAAAACAo/78kEuCc9JqEdhW021zuyYMPXDF8hT0aTACLcB/s640/how%2Bto%2Bcalculate%2BCRC2.png" width="640" /></a></b></div><br /><div style="text-align: justify;"><b>Real scenario : CRC calculation</b></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Note : the <a href="http://www.easteaglefoundation.org/?download=2017/02/Ethernet-II-version-2-DIX-FCS-Frame-Check-Sequence-field.html" target="_blank">previous explanation</a> is adequate for CCNA candidates !</div><div style="text-align: justify;">[post_ad]</div><div style="text-align: justify;">After laying the ground for a little harder CRC, it is time to delve more profoundly in how CRC is calculated and how errors are detected by using binary system, which is the actual language of computers, as well as its representation in mathematical forms that are designed for human beings.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">CRC, error detection mechanism, is based on binary division, and it is often represented in algebraic polynomial for the reasons that it is shorter than the act of writing zeroes and ones to prove the concept mathematically, and also the capacity of being able to be represented in binary pattern. Nevertheless, our explanation will include both CRC code’s representations. </div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Let us first explain how to transform from polynomial to binary representation by considering this example :</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-EgQ4MaAPsp8/WJoaMrYU_xI/AAAAAAAACAY/lZFu1KKTGOkhwZkHAlo8-19R7PTLeWKJACLcB/s1600/how%2Bto%2Bcalculate%2BCRC.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="41" src="https://2.bp.blogspot.com/-EgQ4MaAPsp8/WJoaMrYU_xI/AAAAAAAACAY/lZFu1KKTGOkhwZkHAlo8-19R7PTLeWKJACLcB/s400/how%2Bto%2Bcalculate%2BCRC.png" width="400" /></a></div><!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:TrackMoves/> <w:TrackFormatting/> <w:HyphenationZone>21</w:HyphenationZone> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> 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mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} </style><![endif]--> <br /><div style="text-align: justify;"><span style="color: red;"><b>Rule : </b></span>The power of each term shows the position of the bit; the coefficient shows the value of the bit. To make this rule more easier to understand, follow these steps.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">The transformation above has been done by first looking at the left where we have X8, then we start counting. If we have X to the power of any number (x8), we write ‘1’ which is the case above. Next, we see if the number before the power ‘8’&nbsp; is there, which is, in this case, ‘7’, so we add another ‘1’ (if a number does not exist, we put in its place a zero).Then, we look at the number that comes before 7, which is 6, and the above example does not have X6, so we put ‘0’. After, we add ‘1’ because X5 exists. </div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Afterwards, we add another ‘1’ because x4 is there. After that, we put ‘0’ because there is no X3.&nbsp; Subsequently, we add ‘1’ because we have x2. Following that we add another ‘1’ because we have x, and whenever you see x without a power, it automatically equals x1. Finally, we put ‘1’ because we have 1 ; in the same way, whenever you see 1, it automatically equals x0. This figure summaries all that.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-zRoxzx77nQE/WJoVGK-BO5I/AAAAAAAAB_Q/r3cB2r6nOKI6pZDz5iPv0M0T8wDCwv48ACEw/s1600/CRC%2Bexplanation.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="321" src="https://1.bp.blogspot.com/-zRoxzx77nQE/WJoVGK-BO5I/AAAAAAAAB_Q/r3cB2r6nOKI6pZDz5iPv0M0T8wDCwv48ACEw/s640/CRC%2Bexplanation.png" width="640" /></a></div><br /><div style="text-align: justify;">Now, after knowing how to transform from polynomial to binary, let us employ all that in a CRC operation.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">To calculate CRC value we need a generator value along with the message to be transmitted. The generator (or divisor) is the binary number by which the message’s binary number + appended number (or dividend) is to be divided to get the CRC value. For example, <b>1010100111+0000</b> is the message to be transmitted, and <b>01100 </b>is the generator. However, the division here is a litle bit different. Consider this example.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;"><b>&nbsp;Suppose we have :</b></div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">- CRC generator/ generator polynomial = x5+ x2+1.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">- Data unit to be transmitted =&nbsp; x9 + x6 + x4 + x2 + x</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">- ‘n’ is a string of 0’s appended to the data unit to be transmitted where n is one less than the number of bits in the CRC generator.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Through what statements given we can calculate the CRC value.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">First, we transform the generator polynomial x5+ x2+1 into binary, which gives <b>100101</b>. Then, we transform the data unit to be transmitted from the polynomial x9 + x6 + x4 + x2 + x into binary, which gives <b>1001010110</b> .</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Second, we add ‘n’ string of zeroes to the data unit to be transmitted. As written in the third statement, n is one less than the number of bits in the CRC generator. So we take CRC generator which is <b>100101 </b>and count how many bits there are, and detract one bit. The number of bits is 6 and by detracting 1 bits, it becomes 5 bits, which is the final number of zeroes to be appended at the end of data unit. The whole data unit becomes <b><span style="color: blue;">1001010110</span><span style="color: red;">00000</span></b>.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">Third, we divide the newly formed data unit by the divisor (CRC generator) using binary division. The remainder is called CRC (Cyclic Redundancy Check).</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">The CRC calculation is done as what follows:</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-ROcmp9clqOk/WJoV7Btm33I/AAAAAAAAB_Y/iQjwKn1UOQIb3wXAGy9Z9slTP00tt-BuQCLcB/s1600/CRC%2Bcalculation.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="272" src="https://4.bp.blogspot.com/-ROcmp9clqOk/WJoV7Btm33I/AAAAAAAAB_Y/iQjwKn1UOQIb3wXAGy9Z9slTP00tt-BuQCLcB/s400/CRC%2Bcalculation.png" width="400" /></a></div><br /><div style="text-align: justify;">We first take the data unit to be transmitted plus the appended zeroes in binary, which is the dividend, along with the divisor binary number as arranged in the above figure. Then, we start performing XOR (Exclusive OR) operation which is explained below.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-LUI0ICSKQhc/WJoWNoenycI/AAAAAAAAB_c/znkb439bv5c3GZ-t9tMbIUENGo5vAjP0QCLcB/s1600/CRC%2Bcalculation%2Bpolynomial.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="333" src="https://4.bp.blogspot.com/-LUI0ICSKQhc/WJoWNoenycI/AAAAAAAAB_c/znkb439bv5c3GZ-t9tMbIUENGo5vAjP0QCLcB/s400/CRC%2Bcalculation%2Bpolynomial.png" width="400" /></a></div><div style="text-align: justify;">&nbsp;<b>First step :</b> we take the divisor 100101 and put it in the left under the data unit 100101011000000 (dividend) in this way: </div><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-FOm6HQmtdbI/WJoWbGreMbI/AAAAAAAAB_g/1UL8oU-nIw4syJmEYjQHAJ5-F8bR6OeFQCLcB/s1600/XOR%2Boperation.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://1.bp.blogspot.com/-FOm6HQmtdbI/WJoWbGreMbI/AAAAAAAAB_g/1UL8oU-nIw4syJmEYjQHAJ5-F8bR6OeFQCLcB/s1600/XOR%2Boperation.png" /></a></div><div style="text-align: justify;"><b>Second step :</b> we perform XOR operation. 1 + 1 = 0 /&nbsp; 0 + 0 = 0 /&nbsp; 0 + 0 = 0 / 1 + 1 = 0 / 0 + 0 = 0 / 1 + 1 = 0.&nbsp;&nbsp; The result is : </div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-6Zr_S-4WClk/WJoWqCeQUqI/AAAAAAAAB_k/1S7nOfzrdIw7T59c4gBiNhNqFLUlzGeiQCLcB/s1600/XOR.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/-6Zr_S-4WClk/WJoWqCeQUqI/AAAAAAAAB_k/1S7nOfzrdIw7T59c4gBiNhNqFLUlzGeiQCLcB/s1600/XOR.png" /></a></div><div style="text-align: left;"><br /></div><div style="text-align: left;"></div><div class="separator" style="clear: both; text-align: center;"></div><div style="text-align: justify;"><a href="https://4.bp.blogspot.com/-nN4GDx492zU/WJoW6fpRYkI/AAAAAAAAB_s/00IV1ILI9mcHrUtAH0uq9kuw1kyfKRI1ACLcB/s1600/Exclusive%2BOR.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://4.bp.blogspot.com/-nN4GDx492zU/WJoW6fpRYkI/AAAAAAAAB_s/00IV1ILI9mcHrUtAH0uq9kuw1kyfKRI1ACLcB/s1600/Exclusive%2BOR.png" /></a><b><span style="color: red;">Note :</span> </b>During the calculation we have to ignore the first bit in the left in all XOR operations and put down the bits that have no divisor beneath.</div><br /><br /><br /><br /><br /><div style="text-align: justify;"><b>Third step :</b> we have to look at the first bit in the results. If itstarts with 0, we need to put the divisor’s bit numbers in zeroes 000000; but if the first bit starts with 1, we need to put the actual divisor 100101.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-Z9JMtGDjeEk/WJoXRZ8hgQI/AAAAAAAAB_0/Q4AuUVy_jZ09CGAKoJp_FnVWJ7hVh5H7QCLcB/s1600/XOR-%2Bzeroes.png" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://3.bp.blogspot.com/-yRrO89_NfI0/WJoXRZg-jpI/AAAAAAAAB_4/OfGnTq2uWycuo6d9HDMcYwkbtJVBhrPugCEw/s1600/XOR-ones.png" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://3.bp.blogspot.com/-yRrO89_NfI0/WJoXRZg-jpI/AAAAAAAAB_4/OfGnTq2uWycuo6d9HDMcYwkbtJVBhrPugCEw/s1600/XOR-ones.png" /></a><img border="0" src="https://2.bp.blogspot.com/-Z9JMtGDjeEk/WJoXRZ8hgQI/AAAAAAAAB_0/Q4AuUVy_jZ09CGAKoJp_FnVWJ7hVh5H7QCLcB/s1600/XOR-%2Bzeroes.png" /></div><div class="" style="clear: both; text-align: justify;"><b>Final step : </b>we keep following the same technique until we put down the last appended zero as appeared below</div><div class="separator" style="clear: both; text-align: center;"><a href="https://2.bp.blogspot.com/-Hsxfy10zA2s/WJoYXwzySPI/AAAAAAAACAE/ir0IUDjjj3gern06KQIqfgAupZaRWteywCLcB/s1600/CRC%2Bvalue.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://2.bp.blogspot.com/-Hsxfy10zA2s/WJoYXwzySPI/AAAAAAAACAE/ir0IUDjjj3gern06KQIqfgAupZaRWteywCLcB/s1600/CRC%2Bvalue.png" /></a></div><div style="text-align: justify;">After getting the CRC,&nbsp; the last five zeroes of data unit are replaced with the CRC value ; thus 100101011000000 becomes 100101011011110. This latter is the data plus CRC value that is going to be sent to the receiver. Here the role of the sender is finished.</div><div style="text-align: justify;"><br /></div><div style="text-align: justify;">When the receiver gets the frame, it takes the data unit along with the CRC value and repeat the same calculation using the same divisor. If the final result equals 00000, the data is said to be intact, but if the result is another number, the data would be said to be damaged. Look at the following figure.</div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-LCFx9461smo/WJoYntDoApI/AAAAAAAACAM/DAqyg2pkIIYJH-Z_L0mcQShRvqwCmfyXgCLcB/s1600/CRC-error%2Bdetection.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="267" src="https://1.bp.blogspot.com/-LCFx9461smo/WJoYntDoApI/AAAAAAAACAM/DAqyg2pkIIYJH-Z_L0mcQShRvqwCmfyXgCLcB/s320/CRC-error%2Bdetection.png" width="320" /></a></div><br /><br /><div style="text-align: justify;"><span style="color: red;"><b>I hope you have understood the lesson. If so, please do not forget to give your feedback by commenting on the lesson.</b></span></div><div class="" style="clear: both; text-align: left;">[post_ad]</div></div>M. Bouftirahttps://plus.google.com/110491273114409156931noreply@blogger.com0