Multi-session BGP - BGP routes are removed intermittently and errors are seen in the logs

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Article ID: 168487

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Updated On:

Products

XOS

Issue/Introduction

1. BGP routes are removed on the VAPs, and causes traffic outages.,
2. Log entries similar to those below are displayed in /var/log/messages around the time of the event
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Dec 22 00:03:24 fw_1 BGP[8565]: BGP: [SOCK CB] sock_getpeer() failed (107:Transport endpoint is not connected), FD(27)
Dec 22 00:04:55 fw_1 last message repeated 2 times
Dec 22 00:06:49 fw_1 last message repeated 2 times
Dec 22 00:08:30 fw_1 last message repeated 2 times
Dec 22 00:09:40 fw_1 BGP[8565]: BGP: [SOCK CB] sock_getpeer() failed (107:Transport endpoint is not connected), FD(27)
Dec 22 00:09:40 fw_1 BGP[8565]: BGP: 192.168.195.178-Outgoing [DECODE] Open Cap: unrecognized capability code 131 len 1
Dec 22 00:09:42 fw_1 BGP[8565]: BGP: 192.168.195.177-Outgoing [DECODE] Open Cap: unrecognized capability code 131 len 1
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Dec 22 00:34:44 fw_1 BGP[8565]: BGP: 192.168.157.251-Outgoing [DECODE] Open Cap: unrecognized capability code 131 len 1
Dec 22 00:34:44 fw_1 BGP[8565]: BGP: 192.168.157.250-Outgoing [DECODE] Open Cap: unrecognized capability code 131 len 1

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Dec 22 00:39:09 fw_1 BGP[8565]: BGP: 192.168.157.66-Outgoing [RIB] Withdraw: Can't find route 172.24.185.128/27
Dec 22 00:39:09 fw_1 BGP[8565]: BGP: 192.168.157.66-Outgoing [RIB] Withdraw: Can't find route 172.24.191.0/27
Dec 22 00:39:09 fw_1 BGP[8565]: BGP: 192.168.157.66-Outgoing [RIB] Withdraw: Can't find route 172.24.205.192/26
Dec 22 00:39:10 fw_1 BGP[8565]: BGP: 192.168.157.66-Outgoing [RIB] Withdraw: Can't find route 10.192.202.48/28 

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Cause

BGP neighbors are trying to negotiate multi-session BGP (http://tools.ietf.org/html/draft-ietf-idr-bgp-multisession-03) which is not supported by RSW. This causes BGP capability negotiation to fail. Sometimes, RSW tears down the connection.

Dec 22 00:09:39 fw_1 BGP[8565]: BGP: 192.168.195.177-Outgoing [FSM] InConnReq: Sock-CB Accept Failed for Sock-FD (34)
Dec 22 00:09:42 fw_1 BGP[8565]: BGP: 192.168.195.177-Outgoing [DECODE] Open Cap: unrecognized capability code 131 len 1

However at other times, neighbor tears down the connection. At this time, since the neighbor no longer exists, an error message is printed.

[Dec 22 00:03:24 fw_1 BGP[8565]: BGP: [SOCK CB] sock_getpeer() failed (107:Transport endpoint is not connected), FD(27)

Resolution

Remove the multi-session BGP configuration with the BGP neighbor, and establish a single session BGP connection.