6500, SUP720, 12.2(33)SXI3. Couple of iBGP neighbors keep flapping on one box. Looks like a path-mtu issue, yet the discovered path looks correct:
sh bgp ipv4 unicast summary | i Neighbor|10.116.0.1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.116.0.1 4 65116 165937 690347 268786 0 61 00:00:50 0 path-mtu discovers 9116: Address tracking is enabled, the RIB does have a route to 10.116.0.1 Connections established 3937; dropped 3936 Last reset 00:02:22, due to BGP Notification sent, hold time expired External BGP neighbor may be up to 255 hops away. Transport(tcp) path-mtu-discovery is enabled Connection state is ESTAB, I/O status: 1, unread input bytes: 0 Mininum incoming TTL 0, Outgoing TTL 255 Local host: 10.1.0.1, Local port: 46013 Foreign host: 10.116.0.1, Foreign port: 179 Enqueued packets for retransmit: 2, input: 0 mis-ordered: 0 (0 bytes) Event Timers (current time is 0x146C10A6C): Timer Starts Wakeups Next Retrans 9 5 0x146C121A4 TimeWait 0 0 0x0 AckHold 1 0 0x0 SendWnd 0 0 0x0 KeepAlive 0 0 0x0 GiveUp 0 0 0x0 PmtuAger 1 0 0x0 DeadWait 0 0 0x0 iss: 3884779463 snduna: 3884779560 sndnxt: 3884788712 sndwnd: 16288 irs: 1703625207 rcvnxt: 1703625304 rcvwnd: 16288 delrcvwnd: 96 SRTT: 99 ms, RTTO: 1539 ms, RTV: 1440 ms, KRTT: 49248 ms minRTT: 8 ms, maxRTT: 300 ms, ACK hold: 200 ms Flags: higher precedence, nagle, path mtu capable, path mtu discovery Datagrams (max data segment is 9116 bytes): Rcvd: 4 (out of order: 0), with data: 2, total data bytes: 96 Sent: 5 (retransmit: 5), with data: 3, total data bytes: 9248 Pinging between loopbacks with df-bit and mtu 9156 is successful. Disabling path-mtu on the neighbor session "fixes" the problem. The problem only started occurring after some outages caused the sessions to flap. Anyone seen odd path-mtu related issues? -- Tim:> Sent from New York, NY, United States _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
