{"id":252,"date":"2017-09-21T16:18:39","date_gmt":"2017-09-21T14:18:39","guid":{"rendered":"http:\/\/www.quisted.net\/?p=252"},"modified":"2017-09-21T16:18:39","modified_gmt":"2017-09-21T14:18:39","slug":"ebgp-update-source-multihop","status":"publish","type":"post","link":"https:\/\/www.quisted.net\/index.php\/2017\/09\/21\/ebgp-update-source-multihop\/","title":{"rendered":"eBGP Update-source &#038; multihop"},"content":{"rendered":"<ul>\n<li>Local router find the outgoing interface for the neighbor<\/li>\n<li>the IP of the outgoing interface is used as the source IP by default.<\/li>\n<li>With one link a failure in that link can lose the neighborship.\n<ul>\n<li>\u00a0configure two neighbor commands<\/li>\n<li>Use the loopback interfaces as TCP endpoints<\/li>\n<\/ul>\n<\/li>\n<li>Loopback links between two AS might miss the route to the peer&#8217;s loopback\n<ul>\n<li><strong><span style=\"color: #3366ff;\">fixed with multihop<\/span> <\/strong>(TTL=255 instead of TTL=1)<strong>.<br \/>\n<\/strong><\/p>\n<ul>\n<li>create routes between peers to reach loopback address.<\/li>\n<li>configure <strong><span style=\"color: #339966;\">update-source<\/span><\/strong> <span style=\"color: #000000;\">so the right source-ip is used.<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<pre>R10#(config)router bgp <strong>10<\/strong>\nR10#(config-router)neighbor 20.20.20.20 remote-as <strong>20\n<span style=\"color: #3366ff;\">R10#(config-router)neighbor 20.20.20.20 ebgp-multihop<\/span>\n<span style=\"color: #339966;\">R10#(config-router)neighbor 20.20.20.20 update-source loopback0\n<\/span><\/strong>\nR20#(config)router bgp <strong>20<\/strong>\nR20#(config-router)neighbor 10.10.10.10 remote-as <strong>10\n<span style=\"color: #3366ff;\">R20#(config-router)neighbor 10.10.10.10 ebgp-multihop<\/span><\/strong>\n<strong><span style=\"color: #339966;\">R20#(config-router)neighbor 10.10.10.10 update-source loopback0<\/span>\n<\/strong><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Local router find the outgoing interface for the neighbor the IP of the outgoing interface is used as the source IP by default. With one link a failure in that link can lose the neighborship. \u00a0configure two neighbor commands Use the loopback interfaces as TCP endpoints Loopback links between two AS might miss the route [&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":[12,8],"tags":[],"class_list":["post-252","post","type-post","status-publish","format-standard","hentry","category-bgp","category-route"],"_links":{"self":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/252","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=252"}],"version-history":[{"count":0,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/posts\/252\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/media?parent=252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/categories?post=252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.quisted.net\/index.php\/wp-json\/wp\/v2\/tags?post=252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}