BGP Logs not getting reflected on Intrested (Still not clear)

Lijesh NC · ‎12-21-2009

Hi all,

i have pasted the same question couple of months back(https://supportforums.cisco.com/thread/209549) today came across below situation. BGP was down for 9 Mints but those flaps did not reflect on interface...Still the concept is not clear. Kindly help to get out from where I have struck up...

XX-PE-XX#s int Mu71
Multilink71 is up, line protocol is up
Hardware is multilink group interface
Description: ***** XXXXXX****
Internet address is XX.XX.XX.XX /30
MTU 1500 bytes, BW 3968 Kbit, DLY 100000 usec, rely 255/255, load 1/255
Encapsulation PPP, loopback not set
Keepalive set (10 sec)
DTR is pulsed for 2 seconds on reset
LCP Open, multilink Open
Open: IPCP
Last input 00:00:49, output never, output hang never
Last clearing of "show interface" counters 22:23:20
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 2
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec

XX-PE-XX##s pp mu int mu 71

Multilink71, bundle name is XXXX-TEST-XXXX
Bundle is Distributed
0 lost fragments, 3 reordered, 0 unassigned
1 discarded, 2 lost received, 1/255 load
0x1AC received sequence, 0x15DF8 sent sequence
Member links: 2 active, 0 inactive (max not set, min not set)
Serial0/0/3:0, no frags rcvd
Serial0/0/4:0, no frags rcvd

XX-PE-XX##s log | i 0/0/3:0

XX-PE-XX##s log | i 0/0/4:0

XX-PE-XX##s log | i Multilink71

XX-PE-XX##s log | i XXXXXXX_VRF1
Dec 21 18:24:14.231: %BGP-5-ADJCHANGE: neighbor 192.168.82.26 vpn vrf XXXXXXX_VRF1 Down Peer closed the session
Dec 21 18:33:56.625: %BGP-5-ADJCHANGE: neighbor 192.168.82.26 vpn vrf XXXXXXX_VRF1 Up

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
XX.XX.XX.XX 4 65432 305286 326491 16073942 0 0 00:17:36 7

Lijesh.N.C

marikakis · ‎12-21-2009

I agree with the comments of Giuseppe in the older thread you had posted. There exist cases of interconnection methods where failures on physical media are not reflected very well on router interface status. But there is one more thing. If the interface associated with a BGP session goes down (and assuming there is no other way for rerouting the traffic to the BGP neighbor address), the BGP session will also go down. The inverse is not always true. I mean, if the BGP session went down, this doesn't necessarily mean the interconnection circuit has failed (this is only one of the possibilities). Maybe something else went wrong on the peer BGP router. Do you have access to that router as well to see what happened there and how the event looked from the peer's perspective? Maybe the peer had high CPU load or lack of memory and started dropping sessions for example or any other malfunctions occured there.

Lijesh NC · ‎12-21-2009

Hi marikakis,

Thanks for the quick responce.i dont have access to my client router but will surely try to get the logs.

will be updating soon

Regards

Lijesh