{"id":2899,"date":"2011-05-11T01:54:07","date_gmt":"2011-05-11T07:54:07","guid":{"rendered":"http:\/\/gregsowell.com\/?p=2899"},"modified":"2011-05-03T20:51:56","modified_gmt":"2011-05-04T02:51:56","slug":"cisco-troubleshoot-pos-interface","status":"publish","type":"post","link":"https:\/\/gregsowell.com\/?p=2899","title":{"rendered":"Cisco &#8211; Troubleshoot POS Interface"},"content":{"rendered":"<p>Troubleshooting a POS(Packet Over Sonet) interface is quite different than your standard ethernet interface.  The first thing you will obviously do is a:<\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">show interface POS1\/0\/0<\/code><\/pre>\n<p>If you are down\/down then you obviously aren&#8217;t seeing light across the link and you need to troubleshoot accordingly.  <\/p>\n<p>If you see the link as up\/down, then you are having other issues.  Either encapsulation or sonet issues.  There is a starting article from Cisco that helps you <a href=\"http:\/\/www.cisco.com\/en\/US\/tech\/tk482\/tk607\/technologies_white_paper09186a0080094699.shtml\">trouble shoot up\/down on POS interfaces<\/a>.  If you have had your link up and running for a while, then it is most likely not an encapsulation issue and more likely a sonet issue.  This being the case you will need to do a little debugging.<\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">terminal monitor !enables debug messages to your console\r\ndebug serial interface<\/code><\/pre>\n<p>You will most likely see:<\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">000611: *Apr 26 21:49:04.146 CDT: POS1\/0\/0: HDLC myseq 12, mineseen 0, yourseen 0, line down\r\n000612: *Apr 26 21:49:14.146 CDT: POS1\/0\/0: HDLC myseq 13, mineseen 0, yourseen 0, line down\r\n000613: *Apr 26 21:49:24.146 CDT: POS1\/0\/0: HDLC myseq 14, mineseen 0, yourseen 0, line down<\/code><\/pre>\n<p>By default a sonet interface sends a keepalive every 10 seconds.  Whenever you send a message, your myseq number will increase.  The mineseen is the sequence number of the last acknowledged keepalive you sent to the neighbor.  The yourseen value is the sequence number of the last received keepalive from a neighbor.  As you can see above I&#8217;m sending and I&#8217;m not getting anything back.  So what now?<\/p>\n<p>Now we enable a local loopback on our pos interface.  <\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">interface POS1\/0\/0\r\nloopback internal<\/code><\/pre>\n<p>This loops back to you.  You should now see your debug output look something like the following:<\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">000595: *Apr 26 21:45:24.138 CDT: POS1\/0\/0: HDLC myseq 53, mineseen 0*, yourseen 53, line down (looped)\r\n000596: *Apr 26 21:45:34.138 CDT: POS1\/0\/0: HDLC myseq 54, mineseen 53*, yourseen 54, line down (looped)\r\n000597: *Apr 26 21:45:44.138 CDT: POS1\/0\/0: HDLC myseq 55, mineseen 54*, yourseen 55, line down (looped)\r\n000598: *Apr 26 21:45:54.138 CDT: POS1\/0\/0: HDLC myseq 56, mineseen 55*, yourseen 56, line down (looped)\r\n000599: *Apr 26 21:46:04.138 CDT: POS1\/0\/0: HDLC myseq 57, mineseen 56*, yourseen 57, line down (looped)<\/code><\/pre>\n<p>Notice that the mineseen and the yourseen are starting to correctly increment.  This proves that your interface is working properly.  At this point, you can tell the provider than their equipment went boom boom.<\/p>\n<p>If you want to loop it outward to the provider network you would issue:<\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">interface POS1\/0\/0\r\nloopback line<\/code><\/pre>\n<p>As always with debug commands, be cautious since these commands can consume large amounts of memory.  Also be sure to disable debug when you are done.  If you can&#8217;t remember which debugs you enabled, simply use the remove all command:<\/p>\n<pre class=\"gs-code\"><code class=\"language-plaintext\">un all<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Troubleshooting a POS(Packet Over Sonet) interface is quite different than your standard ethernet interface. The first thing you will obviously do is a: show\u2026<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16,20,8],"tags":[],"class_list":["post-2899","post","type-post","status-publish","format-standard","hentry","category-cisco","category-hardware","category-networking"],"_links":{"self":[{"href":"https:\/\/gregsowell.com\/index.php?rest_route=\/wp\/v2\/posts\/2899","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gregsowell.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gregsowell.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gregsowell.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/gregsowell.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2899"}],"version-history":[{"count":8,"href":"https:\/\/gregsowell.com\/index.php?rest_route=\/wp\/v2\/posts\/2899\/revisions"}],"predecessor-version":[{"id":2908,"href":"https:\/\/gregsowell.com\/index.php?rest_route=\/wp\/v2\/posts\/2899\/revisions\/2908"}],"wp:attachment":[{"href":"https:\/\/gregsowell.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2899"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gregsowell.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2899"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gregsowell.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2899"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}