cisco-nsp at slepicka
Jun 20, 2012, 9:06 AM
Post #2 of 2
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Just a follow up for anyone who googles this. From Cisco:
The problem here is that TCP 3-way handshake is taking more time than expected. In NX-OS MSDP implementation, after triggering 3-way handshake(by calling connect()), we wait for 1ms for it to complete. If the handshake is not complete, we try the same operation in loop for 5 times. Even after 5 such iterations if handshake is not complete, we retry after msdp reconnect interval.
Issue has been fixed as part of "CSCtw53967 N7k-reg: MSDP peers failed to established due to TCP read Error" by increasing wait-time to 50ms and loop count to 50.
Fixed in 6.1(1)S, 6.0(2)S25 and 5.2(4)S
The bug is not externally visible.
-----Original Message-----
From: cisco-nsp-bounces [at] puck [mailto:cisco-nsp-bounces [at] puck] On Behalf Of James Slepicka (c-nsp)
Sent: Thursday, June 07, 2012 9:02 AM
To: cisco-nsp (cisco-nsp [at] puck)
Subject: [c-nsp] Nexus 7k MSDP issue
I'm having trouble establishing an MSDP session between a 7k running 6.0(1) and a 4900M running 12.2(53)SG2. When the 7k (1.1.1.1) attempts to connect to the 4900M (2.2.2.2), it immediately resets the connection. Some info and ethanalyzer output is below. I have a TAC case open but we haven't made much progress, so I'm just reaching out to see if anyone has run into this before.
Thanks,
James
7k# sh ip msdp sum
MSDP Peer Status Summary for VRF "default"
Local ASN: 65000, originator-id: 1.1.1.1
Number of configured peers: 1
Number of established peers: 0
Number of shutdown peers: 0
Peer Peer Connection Uptime/ Last msg (S,G)s
Address ASN State Downtime Received Received
2.2.2.2 0 Inactive 00:02:52 never 0
7k# sh ip msdp event-history tcp
tcp events for MSDP process
2012 May 2 07:15:53.337376 msdp [11883]: : msdp_connect_main(): EXIT, tid 0xb11a6b90
2012 May 2 07:15:53.337006 msdp [11883]: : msdp_open_peer() connect() 2.2.2.2 default Operation already in progress
2012 May 2 07:15:53.335934 msdp [11883]: : connect() returned Operation already in progress
2012 May 2 07:15:53.334701 msdp [11883]: : connect() returned Operation already in progress
2012 May 2 07:15:53.333471 msdp [11883]: : connect() returned Operation already in progress
2012 May 2 07:15:53.332239 msdp [11883]: : connect() returned Operation already in progress
2012 May 2 07:15:53.330996 msdp [11883]: : connect() returned Operation now in progress
2012 May 2 07:15:53.329597 msdp [11883]: : msdp_connect_main(): open peer, tid 0xb11a6b90
2012 May 2 07:15:53.329230 msdp [11883]: : Socket is setup, sid: 43, peer address 2.2.2.2
2012 May 2 07:15:53.328126 msdp [11883]: : msdp_connect_main(): Start Connect thread, tid 0xb11a6b90
2012 May 2 07:15:53.327696 msdp [11883]: : Opened connection with peer 2.2.2.2
2012 May 2 07:15:53.327692 msdp [11883]: : Started thread, We are connect (active) side of connection, using local address 1.1.1.1
2012 May 2 07:15:53.327456 msdp [11883]: : We are connect (active) side of connection, using local address 1.1.1.1
2012 May 2 07:15:53.327449 msdp [11883]: : Retry opening connection with peer 2.2.2.2
No. Time Source Destination Protocol Info
1 2012-05-16 15:17:36.872947 1.1.1.1 2.2.2.2 TCP 46602 > msdp [SYN] Seq=0 Win=16384 Len=0 MSS=536 WS=1 TSval=33148882 TSecr=0
2 2012-05-16 15:17:36.891431 2.2.2.2 1.1.1.1 TCP msdp > 46602 [SYN, ACK] Seq=0 Ack=1 Win=16384 Len=0 MSS=536
3 2012-05-16 15:17:36.891602 1.1.1.1 2.2.2.2 TCP 46602 > msdp [RST] Seq=1 Win=0 Len=0
4 2012-05-16 15:17:46.892898 1.1.1.1 2.2.2.2 TCP 46825 > msdp [SYN] Seq=0 Win=16384 Len=0 MSS=536 WS=1 TSval=33148977 TSecr=0
5 2012-05-16 15:17:46.911616 2.2.2.2 1.1.1.1 TCP msdp > 46825 [SYN, ACK] Seq=0 Ack=1 Win=16384 Len=0 MSS=536
6 2012-05-16 15:17:46.911827 1.1.1.1 2.2.2.2 TCP 46825 > msdp [RST] Seq=1 Win=0 Len=0
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