All things related to multicast

> At 14:37 today MSDP peerings started to reset every few
> minutes.  I brought both the OSU and OARnet routers up to the
> to 12.0.7S (previously running variations of 12.0.6S).

Now, that triggered me: you're not the only one who sees this. :-(

I suppose you see these problems with both 12.0(6)S and 12.0(7)S,
and that the spurious memory accesses only appeared with 12.0(7)S?

We're running 12.0(6)S, and this incessant flapping of our MSDP
sessions appears in our case to have started Oct 28 09:16 UTC,
and now we occasionally get more than one reset per minute.  The
sequence

12:27:09: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going up
12:27:11: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going down
12:27:11: MSDP: 193.10.252.4: Peer reset, exceeded max output queue length
12:27:11: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going up
12:27:18: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going down
12:27:18: MSDP: 193.10.252.4: Peer reset, exceeded max output queue length
12:27:19: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going up
12:27:21: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going down
12:27:21: MSDP: 193.10.252.4: Peer reset, exceeded max output queue length
12:27:27: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going up
12:27:29: %MSDP-5-PEER_UPDOWN: Session to peer 193.10.252.4 going down
12:27:29: MSDP: 193.10.252.4: Peer reset, exceeded max output queue length

appears to be depressingly typical.

I appear to have managed to catch the peer when the queue is
largish (see attachment) -- 97 entries.

This particular peer is 96ms away (across the Atlantic, so not
much we can do about that), so TCP will take a while to ramp up
it's data rate after connection reset (or after a quiescent
period).

I wonder if this isn't exposing a weakness of running MSDP (and in
particular sending the SA messages) over TCP.  Doesn't the current
internet-draft for MSDP specify UDP as an option for encapsulating
SA messages, an option which Cisco currently doesn't implement?  If
I recall, Cisco has also made sounds to the effect that UDP
encapsulation of SA messages isn't on their TODO list either. :-(

The other alternative is of course that this is a more "plain" Cisco
bug. :-)


Regards,

- Håvard
sw-gw#show ip msdp peer 193.10.252.4
MSDP Peer 193.10.252.4 (us-gw.nordu.net), AS 2603
Description: 
  Connection status:
    State: Up, Resets: 46102, Connection source: Loopback0 (193.10.252.5)
    Uptime(Downtime): 00:00:16, Messages sent/received: 3/962
    Output messages discarded: 0
    Connection and counters cleared 6w4d     ago
  SA Filtering:
    Input filter: none, route-map: none
    Output filter: none, route-map: none
  SA-Requests: 
    Input filter: none
    Sending SA-Requests to peer: disabled
  Peer ttl threshold: 0
  Input queue size: 0, Output queue size: 97
  Output queue contents:
    0x619BE700/456 0x619FD578/1400 0x6198A5F8/944 0x6199C9D0/980 
    0x619C4F68/1400 0x619A1090/1400 0x61A42FC8/1400 0x61A37EE8/1400 
    0x6197E368/908 0x619C9F00/800 0x61A32F50/1400 0x619F8EB8/1400 
    0x619E4780/896 0x6197DA90/1400 0x619B7250/944 0x619A07B8/980 
    0x619D0048/1400 0x61966720/1400 0x619D4708/1400 0x619F7430/1400 
    0x61A151C0/908 0x619CB0B0/800 0x61A01360/1400 0x619AD320/1400 
    0x619FF8D8/896 0x6196FD78/1400 0x61A04870/944 0x619A3CC8/980 
    0x619DEF10/1400 0x6197EC40/1400 0x619E8568/1400 0x619E00C0/1400 
    0x61973B60/908 0x61A27E70/800 0x6196D140/1400 0x619D23A8/1400 
    0x61A26CC0/896 0x61978220/1400 0x61A12588/944 0x61876F28/104 
    0x6195F428/980 0x61A1D668/1400 0x6194FC88/1400 0x61A13738/1400 
    0x619E35D0/1400 0x61A09808/908 0x619E1270/800 0x619A7AB0/1400 
    0x619FA940/1400 0x6136CFD0/896 0x619EA8C8/1400 0x619A2240/944 
    0x6195B640/980 0x619A45A0/1400 0x61A0F078/1400 0x6136BE20/1400 
    0x619994C0/1400 0x61A349D8/908 0x619B4EF0/800 0x619EDDD8/1400 
    0x619592E0/1400 0x619CA7D8/896 0x61A074A8/1400 0x61995FB0/944 
    0x61A02DE8/980 0x61968A80/1400 0x61998BE8/1400 0x61956F80/1400 
    0x619CCB38/1400 0x61956F80/1400 0x61998BE8/1400 0x61968A80/1400 
    0x61A02DE8/980 0x61995FB0/944 0x61A074A8/1400 0x619CA7D8/896 
    0x619592E0/1400 0x619EDDD8/1400 0x619B4EF0/800 0x61A349D8/908 
    0x619994C0/1400 0x6136BE20/1400 0x61A0F078/1400 0x619A45A0/1400 
    0x6195B640/980 0x619A2240/944 0x619EA8C8/1400 0x6136CFD0/896 
    0x619FA940/1400 0x619A7AB0/1400 0x619E1270/800 0x61A09808/908 
    0x619E35D0/1400 0x61A13738/1400 0x6194FC88/1400 0x61A1D668/1400 
    0x6195F428/980 0x61A12588/944 0x61978220/1400 0x61A26CC0/896 
    0x619D23A8/1400 0x6196D140/1400 0x61A27E70/800 0x61973B60/908 
    0x619E00C0/1400 0x619E8568/1400 0x6197EC40/1400 0x619DEF10/1400 
    0x619A3CC8/980 0x61A04870/944 0x6196FD78/1400 0x619FF8D8/896 
    0x619AD320/1400 0x61A01360/1400 0x619CB0B0/800 0x61A151C0/908 
    0x619F7430/1400 0x619D4708/1400 0x61966720/1400 0x619D0048/1400 
    0x619A07B8/980 0x619B7250/944 0x6197DA90/1400 0x619E4780/896 
    0x619F8EB8/1400 0x61A32F50/1400 0x619C9F00/800 0x6197E368/908 
    0x61A37EE8/1400 0x61A42FC8/1400 0x619A1090/1400 0x619C4F68/1400 
    0x6199C9D0/980 0x6198A5F8/944 0x619FD578/1400 0x619BE700/456 
    0x6196ADE0/944 0x619C74B4/908 0x619C8478/800 0x619E8E40/944 
    0x61A06BD0/0 0x619FE728/0 0x619D84F0/1400 0x61A1B308/800 
    0x61951FE8/1400 0x6196BF90/1400 0x619C4690/980 0x61991018/944 
    0x61A24088/1400 0x61A21450/896 0x619A33F0/1400 0x61A28748/1400 
    0x619B60A0/800 0x619ECC28/1400 0x619566A8/1400 0x619A6900/980 
    0x619D3558/944 0x619F47F8/1400 0x619E6208/896 0x61A41540/1400 
    0x6195D0C8/1400 0x619CD410/800 0x619879C0/1400 0x61A22ED8/1400 
    0x6195EB50/980 0x6197D1B8/944 0x619B0830/1400 0x619DA850/896 
    0x619CB988/1400 0x619A71D8/1400 0x619605D8/800 0x6136C6F8/1400 
    0x619C08A8/1400 0x61A25238/980 0x619D0920/944 0x61957858/1400 
    0x6194F3B0/896 0x61955DD0/1400 0x619B1108/1400 0x61980FA0/800 
    0x61A20B78/1400 0x61A0B290/1400 0x61A14010/980 0x61990740/944 
    0x61A1A158/1400 0x6197C8E0/896 0x61A298F8/1400 0x61962060/1400 
    0x619A8C60/800 0x61A036C0/620 0x61A314C8/1400 0x6198C080/1400 
    0x619BB038/980 0x61A05A20/944 0x61A1C530/1280 0x61A36D38/0 
    0x619AEFD8/0 0x619C34E0/1400 0x61977948/1400 0x61A02510/1400 
    0x619EE6B0/980 0x6195C7F0/944 0x61A34100/1400 0x61A237B0/860 
    0x619F50D0/1400 0x61A0F950/1400 0x619EB1A0/1400 0x61988B70/1400 
    0x61A2E890/908 0x61989448/860 0x6197F518/1400 0x619F9790/1400 
    0x619DDD60/1400 0x619E7C90/860 0x619BEE20/1400 0x6198F590/1400 
    0x61A3B3F8/884 0x619CE5C0/1400 0x6197A580/1400 0x619FB218/1400 
    0x619CDCE8/896 0x619DD488/1400 0x619B3D40/1400 0x619AB898/1400 
    0x619BB910/920 0x6196DA18/1400 0x61A438A0/1400 0x619A9E10/980 
    0x619BC1E8/944 0x619FBAF0/1400 0x619DE638/860 0x619DCBB0/1400 
    0x61964C98/1400 0x61958A08/1400 0x61A38A5C/732 0x61971800/1400 
    0x619956D8/908 0x619D2C80/1400 0x61A01C38/884 0x61A30BF0/1400 
    0x61A2B380/1400 0x61A001B0/1400 0x6199C0F8/1400 0x619870E8/980 
    0x619F2D70/944 0x6199B820/1400 0x619E3EA8/1400 0x619D8DC8/1400 
    0x61963AE8/908 0x61A2AD14/780 0x619C9628/1400 0x61A40390/1400 
    0x6198E3E0/908 0x61983BD8/1400 0x61A3FAB8/1400 0x61970650/1400 
    0x619D7C18/980 0x61A2A1D0/944 0x61A16370/1400 0x61A25B10/1400 
    0x61950560/1400 0x61982D4C/104 0x619729B0/616 0x619D58B4/259 
    0x619AAFC0/620 0x619A4E78/0 0x6199AB38/0 0x619B87BC/0 
    0x61A2C530/1400 0x619F3648/956 0x61962938/1400 0x61A2DFB8/1400 
    0x6196B6B8/884 0x6195AD68/836 0x61A1F9C8/836 0x619B3468/1400 
    0x61984D88/1400 0x6195BF18/1400 0x61A24960/1400 0x619B19E0/1400 
    0x61969358/824 0x61A18FA8/1400 0x6199DB80/1400 0x61954C20/1400 
    0x619D6190/860 0x619FA068/1400 0x61978AF8/1400 0x619E9718/884 
    0x619B8CD8/956 0x6136D8A8/1400 0x61A07D80/1400 0x619720D8/884 
    0x61A33828/836 0x6198DB08/836 0x61974438/1400 0x619FDE50/1400 
    0x61A1EA40/848 0x6197FDF0/1400 0x61994528/1400 0x619F0A10/968 
    0x619EEF88/896 0x619B4618/1400 0x6198C958/1400 0x61A3F1E0/1400 
    0x61988298/1400 0x619DB128/1004 0x619E5930/1400 0x619DF7E8/1400 
    0x619844B0/980 0x61A0E7A0/1400 0x619B2B90/1400 0x619B6978/944 
    0x61991B08/864 0x619F0138/0 0x61995181/0 0x61A0A9B8/896 
    0x61A21D28/1400 0x61992AA0/944 0x61953198/1400 0x61966FF8/1400 
    0x61A08658/1400 0x61A0A0E0/944 0x619678D0/1400 0x619D9F78/956 
    0x619AF680/1400 0x619BDFE0/520 0x61993C50/1400 0x619AE4D0/1004 
    0x619E73B8/1400 0x61A3AB20/1400 0x61A17520/980 0x61982150/1400 
    0x6199D2A8/1400 0x619F2498/944 0x6199FEE0/1400 0x61A186D0/1400 
    0x61A29020/1400 0x61A27598/944 0x619D4FE0/1400 0x61A0C440/956 
    0x619F6280/1400 0x61A2D6E0/1400 0x619D96A0/968 0x619C6118/1400 
    0x619E6AE0/1400 0x6199F608/1004 0x61A03F98/1400 0x61A2FA40/1400 
    0x619A5750/980 0x619FF084/1268 0x61975EC0/1352 0x61977131/1207 
    0x6136E180/1292 0x619D3E30/1280 0x61A05148/1400 0x61A39970/1400 
    0x61A113D8/1400 0x61963210/1400 0x61A426F0/704 0x61A352B0/716 
    0x61986810/1280 0x6198D230/1400 0x61A30318/1400 0x61A3CE80/680 
    0x6196EBC8/1328 0x619DBA00/1400 0x619E9FF0/1400 0x61969C30/1400 
    0x619BA760/1400 0x619C3DB8/1304 0x61959BB8/1400 0x61997160/1400 
    0x61951710/728 0x61953A70/1280 0x61A19880/1400 0x61A36460/1400 
    0x619ADBF8/680 0x61A32678/1304 0x61950E38/1400 0x619F12E8/1400 
    0x61993378/716 0x619A6028/1280 0x619F3F20/1400 0x619C8D50/1400 
    0x619AA6E8/1400 0x61A17DF8/1400 0x619AC170/704 0x6199AF48/716 
    0x61989D20/1280 0x61A2032D/1259 0x619BFFD0/0 0x619806C8/0 
    0x619755E8/0 0x619DC2D8/0 0x6199E458/0 0x61970F28/0 
    0x619A2F2C/0 0x6197C008/0 0x61A263E8/0 0x61A1F0F0/0 
    0x619F59A8/0 0x61A3C5A8/0 0x61973288/0 0x61A3E908/0 
    0x619643C0/0 0x6195FD00/0 0x61A1D1B5/0 0x61A062F8/680 
    0x61A104E8/0 0x61998310/0 0x61A31DA0/0 0x619C7BA0/0 
    0x619655D0/0 0x619C1A58/1088 0x619F6B58/0 0x619C2330/0 
    0x61A08F30/0 0x619D7340/0 0x6196A508/0 0x61979CA8/0 
    0x6196C868/0 0x619E2420/0 0x619C2F0B/0 0x619554F8/0 
    0x619A8388/0 0x619BF6F8/0 0x619AFF58/0 0x619C5840/0 
    0x61A0BB68/0 0x619ACA48/0 0x619CF9ED/0 0x61A148E8/980 
    0x61A37610/980 0x619ED500/1028 0x61996888/1400 0x619C1180/968 
    0x61997A38/1400 0x619E5058/1400 0x61A35B88/788 0x619793D0/1064 
    0x619B22B8/1400 0x61A16C48/968 0x619B7B28/1400 0x6195A490/968 
    0x619D6A68/1400 0x619B9E88/1400 0x61A3E030/968 0x61954348/968 
    0x61A40C68/1400 0x61A1AA30/968 0x61A1E2F7/77 0x619FC3C8/980 
    0x619A9538/944 0x61983300/944 0x61A0DEC8/1400 0x61960EB0/956 
    0x6199ED30/1400 0x619EC350/1400 0x6198FE68/944 0x61974D10/1400 
    0x61952ACE/466 0x6197B730/0 0x6198AED0/0 0x619B57C8/0 
    0x619E1B48/0 0x619F85E0/0 0x61965E48/0 0x6197AE58/944 
    0x619BD398/968 0x61A41E18/992 0x61A10B00/1400 0x619C69F0/1004 
    0x619D11F8/968 0x61981878/1004 0x61985660/1400 0x619D1AD0/1400 
    0x61A3A248/980 0x61999D98/980 0x61A1BBE0/980 0x619CEE98/1400 
    0x61A2CE08/968 0x6195D9A0/980 0x61A3D758/1400 0x619CC4C0/72 
sw-gw#