[j-nsp] BGP neighbor state flapping

[Hahn, Ch]

Hi all,

Recently I saw some issues with a flapping BGP session I did not understand. We have a IPv6 peering running between a Cisco and an M5 with JUNOS 6.4R2.4. For unknown reason the session flapped for some time all 2-4 minutes. This was in an lab environment so we had no alarms set up and I only can figure out what happend using the traces the box recorded. 
In the logs I saw the same messages repeating and repeating:

------------------------
May 26 08:01:45 trace_on: Tracing to "/var/log/xxxx" started
May 26 08:01:45 bgp_event: peer 2001:xxxx::1 (Internal AS xxxxx) old state Idle event Start new state Active
May 26 08:01:57 bgp_event: peer 2001:xxxx::1 (Internal AS xxxxx) old state Active event Stop new state Active
May 26 08:02:29 bgp_event: peer 2001:xxxx::1 (Internal AS xxxxx) old state Active event ConnectRetry new state Connect
May 26 08:02:29 bgp_event: peer 2001:xxxx::1 (Internal AS xxxxx) old state Connect event Open new state OpenSent
May 26 08:02:29 bgp_send: sending 45 bytes to 2001:xxxx::1 (Internal AS xxxxX)
May 26 08:02:29 
May 26 08:02:29 BGP SEND 2001:xxxx::2+3209 -> 2001:xxxx::1+179
May 26 08:02:29 BGP SEND message type 1 (Open) length 45
May 26 08:02:29 
May 26 08:02:29 BGP RECV 2001:xxxx::1+179 -> 2001:xxxx::2+3209
May 26 08:02:29 BGP RECV message type 1 (Open) length 45
May 26 08:02:29 bgp_event: peer 2001:xxxx::1 (Internal AS xxxxx) old state OpenSent event RecvOpen new state OpenConfirm
May 26 08:02:29 bgp_event: peer 2001:xxxx::1 (Internal AS xxxxx) old state OpenConfirm event RecvKeepAlive new state Established
------------------------

After some minutes it's started again with "trace_on: Tracing to "/var/log/xxxx" started"

Could it be that we had an daemon problem on the box? Is the above log entry indicating that the bgp process was restarted? 
After some time the peering was stable again without any additional notices in the traces.
Has anybody seen such a behaviour before? Any hint would be really appreciated.

regards,
Christian Hahn

<><><><><><><><><><><><><><>
Christian Hahn

T-Systems International GmbH
IBU Telco, SSC ENPS PCT10
IP-Technologies
Goslarer Ufer 35, D-10589 Berlin
phone:  +49 (0)30 3497 3164
fax: 	  +49 (0)30 3497 3165
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E-Mail: hahnc at t-systems.com
WWW: <<http://www.t-systems.com>>