{"id":146,"date":"2017-09-15T12:18:21","date_gmt":"2017-09-15T10:18:21","guid":{"rendered":"http:\/\/www.quisted.net\/?p=146"},"modified":"2017-09-15T12:18:21","modified_gmt":"2017-09-15T10:18:21","slug":"ospf-stub-area","status":"publish","type":"post","link":"https:\/\/www.quisted.net\/index.php\/2017\/09\/15\/ospf-stub-area\/","title":{"rendered":"OSPF Stub Areas"},"content":{"rendered":"<p>There are four types of stub areas<\/p>\n<ul>\n<li><strong>stub<\/strong><\/li>\n<li><strong><span style=\"color: #3366ff;\">totally<\/span>-stubby<\/strong><\/li>\n<li><strong>not-so-stubby areas (NSSA)<\/strong><\/li>\n<li><strong><span style=\"color: #3366ff;\">totally<\/span> not-so-stubby areas<\/strong><\/li>\n<li>All stub areas do not allow Type 5 (external) LSAs (ABR always filters them)<\/li>\n<li>For the <strong><span style=\"color: #3366ff;\">totally stub<\/span><\/strong> areas the ABR filters the Type 3 LSAs.<\/li>\n<\/ul>\n<p><!--more--><\/p>\n<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 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/www.quisted.net\/index.php\/2017\/09\/15\/ospf-stub-area\/#Stub_areas\" >Stub areas<\/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\/2017\/09\/15\/ospf-stub-area\/#Totally_Stubby_areas\" >Totally Stubby areas<\/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\/2017\/09\/15\/ospf-stub-area\/#Not-so-stubby_area_NSSA\" >Not-so-stubby area (NSSA)<\/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\/2017\/09\/15\/ospf-stub-area\/#Totally_Not-so-stubby_area_NSSA\" >Totally Not-so-stubby area (NSSA)<\/a><\/li><\/ul><\/nav><\/div>\n<h3><span class=\"ez-toc-section\" id=\"Stub_areas\"><\/span><strong>Stub areas<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><a href=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2017\/09\/stubarea.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-148 size-full\" src=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2017\/09\/stubarea.png\" alt=\"\" width=\"725\" height=\"319\" srcset=\"https:\/\/www.quisted.net\/wp-content\/uploads\/2017\/09\/stubarea.png 725w, https:\/\/www.quisted.net\/wp-content\/uploads\/2017\/09\/stubarea-300x132.png 300w\" sizes=\"auto, (max-width: 725px) 100vw, 725px\" \/><\/a><\/p>\n<p>R1(config-router)# area 1 stub<br \/>\nR1(config-router)# area 1 default-metric (metric)<\/p>\n<ul>\n<li>stub has to be defined on both routers (Neighbor goes down with mismatch)<\/li>\n<li>ABR (R2) creates a <span style=\"color: #339966;\">default route<\/span> into the stub area\n<ul>\n<li><em>O*IA 0.0.0.0\/0 [110\/11] via 10.10.10.2, 00:33:10, FastEthernet0\/0<br \/>\n<\/em><\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #ff9900;\">inter area routes<\/span> are allowed<\/li>\n<\/ul>\n<pre>R1#sh ip route\n     1.0.0.0\/24 is subnetted, 2 subnets\nC       1.1.0.0 is directly connected, Loopback2\nC       1.1.1.0 is directly connected, Loopback1\n     2.0.0.0\/24 is subnetted, 1 subnets\n<strong><span style=\"color: #ff9900;\">O IA    2.2.2.0 [110\/20] via 10.10.10.2, 00:43:52, FastEthernet0\/0\n     3.0.0.0\/32 is subnetted, 1 subnets\nO IA    3.3.3.3 [110\/21] via 10.10.10.2, 00:43:52, FastEthernet0\/0\n     20.0.0.0\/32 is subnetted, 1 subnets<\/span><\/strong>\nO       20.20.20.20 [110\/11] via 10.10.10.2, 00:43:52, FastEthernet0\/0\n     10.0.0.0\/24 is subnetted, 1 subnets\nC       10.10.10.0 is directly connected, FastEthernet0\/0\n<strong><span style=\"color: #339966;\">O*IA 0.0.0.0\/0 [110\/11] via 10.10.10.2, 00:43:54, FastEthernet0\/0\n<\/span><\/strong><\/pre>\n<pre>Open Shortest Path First  <span style=\"color: #ff0000;\"><strong>(STUB ROUTER HELLO)<\/strong><\/span>\nOSPF Header\nOSPF Hello Packet\nNetwork Mask: 255.255.255.0\nHello Interval [sec]: 10\nOptions: 0x10 ((L) LLS Data block)\n0... .... = DN: Not set\n.0.. .... = O: Not set\n..0. .... = (DC) Demand Circuits: Not supported\n...1 .... = (L) LLS Data block: Present\n.... 0... = (N) NSSA: Not supported\n.... .0.. = (MC) Multicast: Not capable\n<span style=\"color: #ff0000;\"><strong>.... ..0. = (E) External Routing: Not capable<\/strong><\/span>\n.... ...0 = (MT) Multi-Topology Routing: No\nRouter Priority: 1\nRouter Dead Interval [sec]: 40\nDesignated Router: 10.10.10.2\nBackup Designated Router: 10.10.10.1\nActive Neighbor: 20.20.20.2<\/pre>\n<h3><span class=\"ez-toc-section\" id=\"Totally_Stubby_areas\"><\/span>Totally Stubby areas<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>R2(config-router)# area 1 stub <strong>no-summary<\/strong><\/p>\n<ul>\n<li>Only has to be defined on the ABR (R2)<\/li>\n<li><span style=\"color: #ff9900;\"><strong>Type 3 summery LSA<\/strong><\/span> are not allowed and are not displayed in the route table<\/li>\n<\/ul>\n<pre>R1#sh ip route\u00a0 \n1.0.0.0\/24 is subnetted, 2 subnets\nC 1.1.0.0 is directly connected, Loopback2\nC 1.1.1.0 is directly connected, Loopback1\n 20.0.0.0\/32 is subnetted, 1 subnets\nO 20.20.20.20 [110\/11] via 10.10.10.2, 00:46:05, FastEthernet0\/0\n 10.0.0.0\/24 is subnetted, 1 subnets\nC 10.10.10.0 is directly connected, FastEthernet0\/0\n<strong><span style=\"color: #339966;\">O*IA 0.0.0.0\/0 [110\/11] via 10.10.10.2, 00:43:54, FastEthernet0\/0\n<\/span><\/strong><\/pre>\n<p>sh ip ospf<br \/>\nsh ip ospf database<br \/>\nsh ip ospf database database-summary<\/p>\n<h3><span class=\"ez-toc-section\" id=\"Not-so-stubby_area_NSSA\"><\/span>Not-so-stubby area (NSSA)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p><a href=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2017\/09\/nssa.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-162 size-full\" src=\"http:\/\/vps.quisted.net\/wp-content\/uploads\/2017\/09\/nssa.png\" alt=\"\" width=\"740\" height=\"344\" srcset=\"https:\/\/www.quisted.net\/wp-content\/uploads\/2017\/09\/nssa.png 740w, https:\/\/www.quisted.net\/wp-content\/uploads\/2017\/09\/nssa-300x139.png 300w\" sizes=\"auto, (max-width: 740px) 100vw, 740px\" \/><\/a><\/p>\n<p>R1(config-router)# area 1 nssa<\/p>\n<ul>\n<li>external routes cannot be injected to stub\/totally stubby. Routes within the area can&#8217;t redistribute<\/li>\n<li>NSSA are used for ASBR within a stub area to redistribute.<\/li>\n<li>ASBR within a NSSA creates a <span style=\"color: #ff6600;\">Type 7 NSSA-External LSA.<\/span><\/li>\n<li>If an ABR receives a <span style=\"color: #ff6600;\">Type 7 NSSA-External LSA<\/span> it forwards a <span style=\"color: #008000;\">Type 5 LSA.<\/span><\/li>\n<li>ABRs Type 3 LSA are still advertized (same as stub area).<\/li>\n<li>ABRs will <strong>not<\/strong> create a default route (different than stub area).\n<ul>\n<li><em>R1(config-router)# area 1 nssa default-information-originate<\/em><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre>R1#sh ip ospf database nssa-external\n\n     OSPF Router with ID (1.1.1.1) (Process ID 1)\n     <strong><span style=\"color: #ff00ff;\">Type-7 AS External<\/span> Link States (Area 1)<\/strong>\nLS age: 29\nOptions: (No TOS-capability, <span style=\"color: #ff00ff;\"><strong>Type 7\/5 translation, DC)<\/strong><\/span>\nLS Type: AS External Link\nLink State ID: 1.1.1.0 (External Network Number )\nAdvertising Router: 1.1.1.1\nLS Seq Number: 80000001\nChecksum: 0x3656\nLength: 36\nNetwork Mask: \/24\n      Metric Type: 2 (Larger than any link state path)\n     TOS: 0\n     Metric: 20\n     Forward Address: 1.1.0.1\n     External Route Tag: 0\n\n\nR2# sh ip route\n 1.0.0.0\/8 is variably subnetted, 2 subnets, 2 masks\n<span style=\"color: #ff00ff;\"><strong>O N2 1.1.1.0\/24 [110\/20] via 10.10.10.1, 00:03:16, FastEthernet0\/0<\/strong><\/span>\nO 1.1.0.1\/32 [110\/11] via 10.10.10.1, 00:08:22, FastEthernet0\/0\n 2.0.0.0\/24 is subnetted, 1 subnets\nC 2.2.2.0 is directly connected, FastEthernet0\/1\n 3.0.0.0\/32 is subnetted, 1 subnets\nO 3.3.3.3 [110\/11] via 2.2.2.1, 00:09:29, FastEthernet0\/1\n 20.0.0.0\/24 is subnetted, 1 subnets\nC 20.20.20.0 is directly connected, Loopback0\n 10.0.0.0\/24 is subnetted, 1 subnets\nC 10.10.10.0 is directly connected, FastEthernet0\/0\n<\/pre>\n<h3><span class=\"ez-toc-section\" id=\"Totally_Not-so-stubby_area_NSSA\"><\/span>Totally Not-so-stubby area (NSSA)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n<p>R1(config-router)# area 1 nssa no-summy<\/p>\n<ul>\n<li>ABR doesnt inject Type 3 LSAs in de area (same as totally stubby)<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>There are four types of stub areas stub totally-stubby not-so-stubby areas (NSSA) totally not-so-stubby areas All stub areas do not allow Type 5 (external) LSAs (ABR always filters them) For the totally stub areas the ABR filters the Type 3 LSAs.<\/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":[14,8],"tags":[],"class_list":["post-146","post","type-post","status-publish","format-standard","hentry","category-ospf","category-route"],"_links":{"self":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/146","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=146"}],"version-history":[{"count":0,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/146\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/media?parent=146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/categories?post=146"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/tags?post=146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}