{"id":736,"date":"2018-02-13T09:37:00","date_gmt":"2018-02-13T08:37:00","guid":{"rendered":"http:\/\/www.quisted.net\/?p=736"},"modified":"2018-02-13T09:37:00","modified_gmt":"2018-02-13T08:37:00","slug":"is-is-design-principles","status":"publish","type":"post","link":"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/","title":{"rendered":"IS-IS Design Principles"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_80 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#IS-IS_History\" >IS-IS History<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#IS-IS_High_level_Design\" >IS-IS High level Design<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#IS-IS_Neighbors_and_Area_Design\" >IS-IS Neighbors and Area Design<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#NSAP_Addressing\" >NSAP Addressing<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#IS-IS_Modes_of_Operation\" >IS-IS Modes of Operation<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#Flat_Design\" >Flat Design<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#Herarchical_Design\" >Herarchical Design<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/www.quisted.net\/index.php\/2018\/02\/13\/is-is-design-principles\/#Three_Tier_Hirarchy\" >Three Tier Hirarchy:<\/a><\/li><\/ul><\/nav><\/div>\n<h3><span class=\"ez-toc-section\" id=\"IS-IS_History\"><\/span><span style=\"color: #3366ff;\"><strong>IS-IS History<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><a href=\"https:\/\/en.wikipedia.org\/wiki\/IS-IS\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/IS-IS<\/a><br \/>\n<a href=\"https:\/\/en.wikipedia.org\/wiki\/OSI_protocols\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/OSI_protocols<\/a><br \/>\n<a href=\"https:\/\/en.wikipedia.org\/wiki\/Type-length-value\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/Type-length-value<\/a><\/p>\n<ul>\n<li>Created for the <strong><span style=\"color: #993366;\"><em>OSI Protocol Suite<\/em><\/span><\/strong><\/li>\n<li>Integrated IS-IS: the mutation.<\/li>\n<li>IS-IS dictionary:\n<ul>\n<li><span style=\"color: #993366;\"><strong>IS<\/strong><\/span> = Intermediate System\u00a0 (Routers)<\/li>\n<li><span style=\"color: #993366;\"><strong>ES<\/strong><\/span> = End System<\/li>\n<li><span style=\"color: #993366;\"><strong>TLV<\/strong><\/span> = Type Length Value<\/li>\n<li><span style=\"color: #993366;\"><strong>NSAP<\/strong><\/span> = Network Service Access Point\n<ul>\n<li><em>(OSI protocols equivilent of the TCP\/IP&#8217;s IP Address)<\/em><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #ff0000;\"><strong>IS-IS features:<\/strong><\/span>\n<ul>\n<li>Link State Routing Protocol\u00a0 (Same as <strong>OSPF)<\/strong><\/li>\n<li>NSAP address assigned per router<\/li>\n<li><strong>Dijkstra SPF<\/strong> powered (Same as <strong>OSPF)<\/strong>\n<ul>\n<li>PRC efficient<\/li>\n<\/ul>\n<\/li>\n<li><em>Hellos<\/em> Establisch neighbors at Layer 2 ( source MAC, Multicast Mac )<\/li>\n<li>Two routing levels ( <strong>Level 1 and Level 2<\/strong> )<\/li>\n<li>Area Based Design ( Routers know their area )<\/li>\n<li>default link cost = 10<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"IS-IS_High_level_Design\"><\/span><span style=\"color: #993366;\"><strong>IS-IS High level Design<\/strong><\/span><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li><strong>Two routing databases<\/strong>\n<ul>\n<li>Level1 and Level2\n<ul>\n<li>Level 1 routers find closest <em><strong>Level2 Exit.<\/strong><\/em><\/li>\n<\/ul>\n<\/li>\n<li>Area defined by<\/li>\n<li><strong>49.0001<\/strong>\u00a0 ( Area 1 )\n<ul>\n<li><strong>49<\/strong> private adressing , <strong>0001<\/strong> is area 1<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Three router types<\/strong><\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"IS-IS_Neighbors_and_Area_Design\"><\/span><strong><span style=\"color: #3366ff;\">IS-IS Neighbors and Area Design<\/span><br \/>\n<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><a href=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISISArea.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-749\" src=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISISArea.png\" alt=\"\" width=\"412\" height=\"302\" srcset=\"https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISISArea.png 412w, https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISISArea-300x220.png 300w\" sizes=\"auto, (max-width: 412px) 100vw, 412px\" \/><\/a><\/p>\n<p><!--more--><\/p>\n<ul>\n<li>Router types defined, neighbors constricted<\/li>\n<li>Router is in one area ( Level1 ), links can lead to other areas ( Level 2 )<\/li>\n<li><strong>Level1<\/strong> Neighbors only speak to <strong>Level1<\/strong> Area<\/li>\n<li><strong>Level2<\/strong> Neighbors can be in the <strong>same<\/strong> or <strong>different<\/strong> Areas<\/li>\n<li>Neighbor authentication possible<\/li>\n<\/ul>\n\n<table id=\"tablepress-9\" class=\"tablepress tablepress-id-9\">\n<thead>\n<tr class=\"row-1\">\n\t<th class=\"column-1\">OSPF<\/th><th class=\"column-2\">IS-IS<\/th>\n<\/tr>\n<\/thead>\n<tbody class=\"row-striping row-hover\">\n<tr class=\"row-2\">\n\t<td class=\"column-1\">Area borders inside router<\/td><td class=\"column-2\">Routers in one Area<\/td>\n<\/tr>\n<tr class=\"row-3\">\n\t<td class=\"column-1\">Link in one Area<\/td><td class=\"column-2\">Links define Area Borders<\/td>\n<\/tr>\n<tr class=\"row-4\">\n\t<td class=\"column-1\">Backbone extensions can be difficult<\/td><td class=\"column-2\">Backbone is easy to extend<\/td>\n<\/tr>\n<tr class=\"row-5\">\n\t<td class=\"column-1\">IP Based, IP Powered<\/td><td class=\"column-2\">CLNS* (NSAP) Addresses define Routing<\/td>\n<\/tr>\n<tr class=\"row-6\">\n\t<td class=\"column-1\"><\/td><td class=\"column-2\">IP Carried in a backpack ( TLV )<\/td>\n<\/tr>\n<tr class=\"row-7\">\n\t<td class=\"column-1\">Metric = Cost ( bandwidth based )<\/td><td class=\"column-2\">Metric is 1O\/ You can create the system<\/td>\n<\/tr>\n<tr class=\"row-8\">\n\t<td class=\"column-1\">Widley known and supported<\/td><td class=\"column-2\">Less known<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<!-- #tablepress-9 from cache -->\n<ul>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Connectionless-mode_Network_Service\" target=\"_blank\" rel=\"noopener\">https:\/\/en.wikipedia.org\/wiki\/Connectionless-mode_Network_Service<\/a><\/li>\n<\/ul>\n<h3><span class=\"ez-toc-section\" id=\"NSAP_Addressing\"><\/span><strong><span style=\"color: #3366ff;\">NSAP Addressing<\/span><br \/>\n<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>Original implementation of OSI defined five fields the NSAP address would represent<\/li>\n<li>Cisco&#8217;s implementation of IS-IS only uses three of those fields\n<ul>\n<li><strong><span style=\"color: #ff0000;\">The Area Address<\/span><\/strong><\/li>\n<li><strong><span style=\"color: #ff0000;\">The System ID<\/span><\/strong><\/li>\n<li><strong><span style=\"color: #ff0000;\">The NSAP Selector ( NSEL )<\/span><\/strong><\/li>\n<\/ul>\n<\/li>\n<li>Example address:\n<ul>\n<li><strong><span style=\"color: #993366;\"><span style=\"color: #3366ff;\">49.1234<\/span>.<span style=\"color: #339966;\">aa15.b322.1841<\/span>.00<\/span><\/strong>\n<ul>\n<li>Reading from right to left:\n<ul>\n<li>00 defines an IS<\/li>\n<li>System ID ( MAC address in this case )<\/li>\n<li>AREA<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li><strong>Addressing rules:<\/strong>\n<ul>\n<li>NSAP Addresses can be up to <strong>20 bytes<\/strong><\/li>\n<li>Last byte of the address is always <strong>00 <\/strong>and it identifies an IS ( a router )<\/li>\n<li>System ID is always a fixed 6 bytes in length<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre>R1(config)#router isis\nR1(config-router)#net\nR1(config-router)#net ?\nXX.XXXX. ... .XXX.XX Network entity title (NET)\n\nR1(config-router)#net <strong>49.0001.1111.1111.1111.00\n<\/strong>\n<\/pre>\n<h3><span class=\"ez-toc-section\" id=\"IS-IS_Modes_of_Operation\"><\/span><strong><span style=\"color: #3366ff;\">IS-IS Modes of Operation<\/span><br \/>\n<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<ul>\n<li>IS-IS supports two modes of operation:\n<ul>\n<li><strong><span style=\"color: #ff0000;\"><em>Broadcast.<\/em><\/span><\/strong><\/li>\n<li><strong><span style=\"color: #ff0000;\"><em>Point-to-Point.<\/em><\/span><\/strong><\/li>\n<\/ul>\n<\/li>\n<li>Modes generate different <em>IS-IS Hello<\/em> (IIH) Messages.<\/li>\n<li>Prevents NBMA cloud designs.<\/li>\n<li>Two accepted designs:\n<ul>\n<li>\n<h2><span class=\"ez-toc-section\" id=\"Flat_Design\"><\/span><strong>Flat Design<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li>One area<\/li>\n<li>L1 or L2 mode only ( Saves resources )<\/li>\n<li>Cisco recommendation <strong>L2\u00a0 <\/strong><em>( creates a backbone )<\/em><strong><br \/>\n<\/strong><\/p>\n<ul>\n<li><a href=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISISflat-1.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-764 size-full\" src=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISISflat-1.png\" alt=\"\" width=\"362\" height=\"242\" srcset=\"https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISISflat-1.png 362w, https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISISflat-1-300x201.png 300w\" sizes=\"auto, (max-width: 362px) 100vw, 362px\" \/><\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<li>\n<h2><span class=\"ez-toc-section\" id=\"Herarchical_Design\"><\/span><strong>Herarchical Design<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li>Large network \/ scalable<\/li>\n<li>Follow the Three Tier Hierarchy<\/li>\n<li><a href=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISIShierarchical.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-762\" src=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISIShierarchical.png\" alt=\"\" width=\"362\" height=\"422\" srcset=\"https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISIShierarchical.png 362w, https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISIShierarchical-257x300.png 257w\" sizes=\"auto, (max-width: 362px) 100vw, 362px\" \/><\/a><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"Three_Tier_Hirarchy\"><\/span><strong>Three Tier Hirarchy:<br \/>\n<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><a href=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISIS3tier.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-766\" src=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2018\/02\/ISIS3tier.png\" alt=\"\" width=\"622\" height=\"404\" srcset=\"https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISIS3tier.png 622w, https:\/\/www.quisted.net\/wp-content\/uploads\/2018\/02\/ISIS3tier-300x195.png 300w\" sizes=\"auto, (max-width: 622px) 100vw, 622px\" \/><\/a><\/p>\n<ul>\n<li>Summerization supported L1 -&gt; L2<\/li>\n<li>External (redistribution) L1\u00a0 -&gt; or L2<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>IS-IS History https:\/\/en.wikipedia.org\/wiki\/IS-IS https:\/\/en.wikipedia.org\/wiki\/OSI_protocols https:\/\/en.wikipedia.org\/wiki\/Type-length-value Created for the OSI Protocol Suite Integrated IS-IS: the mutation. IS-IS dictionary: IS = Intermediate System\u00a0 (Routers) ES = End System TLV = Type Length Value NSAP = Network Service Access Point (OSI protocols equivilent of the TCP\/IP&#8217;s IP Address) IS-IS features: Link State Routing Protocol\u00a0 (Same as OSPF) NSAP [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0,"footnotes":""},"categories":[2,5],"tags":[54],"class_list":["post-736","post","type-post","status-publish","format-standard","hentry","category-arc","category-designprinciples","tag-is-is"],"_links":{"self":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/736","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/comments?post=736"}],"version-history":[{"count":0,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/736\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/media?parent=736"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/categories?post=736"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/tags?post=736"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}