Re: Strangeness at MAE-East

["Alex.Bligh" <amb () xara net>]

> I seem to have lost connectivity across MAE-East to a group of
> peers.  It appears to have come back at about 1:00PM Eastern
> time.  I've attached some snippets from our BGP table, anyone
> know what may have happened, and what is common to these
> peers that dropped thier sessions?

I would suspect that all the peers you mention are in Boone Boulevard
and probably all on shared FDDI (certainly we are - AS5413). This appears
to have been doing all sorts of strange things. I had MFS change our
physical port on the FDDI card, the jumper fibre, and the concentrator
port and it makes no difference. Symptoms are (if you want to try it)
do a 8000 byte 8000 packet ping to something not on shared FDDI
and it will all work fine for (say) 30 seconds. But occasionally there
is the odd 10 seconds of slowness and/or 50% packet loss, and the odd
5 second blackout. If you look at UPDOWN logs, you may see a bounce
one or two times an hour where the i/f went down (we sort 30 yesterday).

MFS is currently blaming our FDDI card - I think I'm blaming congestion
as there is currently only one, unmanaged concentrator serving all
shared FDDI clients.

If anyone else on shared FDDI can see similar problems, I'd be really
grateful to hear about it as though MFS have been pretty helpful in
swapping things out, they have now swapped everything except the
concentrator itself (and, of course, the topology :-) ). This will help
me greatly in proving my congestion / dead concentrator thesis.

Alxe Bligh
Xara Networks


> Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State
>
> [snip]
>
> 192.41.177.65   4  6205   32618   72819  2428592    0    0 07:48:39
> 192.41.177.73   4  6082   16026   56940  2428592    0    0 07:47:15
> 192.41.177.75   4  3951   48247   56693  2428593    0    0 1w4d
>
> [snip]
>
> 192.41.177.113  4  3549   16133   56706  2428593    0    0 1w3d
> 192.41.177.117  4  6079   16245   56869  2428593    0    0 07:47:49
> 192.41.177.118  4  6196   16160   56661  2428593    0    0 6d16h
> 192.41.177.122  4  1299   17874   56841  2428593    0    0 3d07h
> 192.41.177.132  4  3257   16163   57035  2428593    0    0 07:47:45
> 192.41.177.147  4  3847   18249   56666  2428593    0    0 2d20h
>
> [snip]
>
> 192.41.177.160  4  3407   48456   56732  2428593    0    0 4d09h
> 192.41.177.166  4  2885   20740   56618  2428593    0    0 07:47:28
> 192.41.177.169  4  2885   20599   56815  2428593    0    0 1d07h
>
> [snip]
>
> 192.41.177.182  4  5683   18340   56875  2428593    0    0 4d08h
> 192.41.177.183  4  5683   18370   57018  2428593    0    0 07:47:47
> 192.41.177.192  4  2548   41322   52346  2428593    0    0 2d12h
>
> [snip]
>
> 192.41.177.210  4  2551   21995   56687  2428593    0    0 1w4d
> 192.41.177.215  4  5413  165794   58802  2428593    0    0 07:47:51
> 192.41.177.228  4  4006   16269   56949  2428593    0    0 1d21h
>
> [snip]
>
> 192.41.177.242  4  1239  184562   56686  2428593    0    0 1w4d
> 192.41.177.245  4   174   57149   57069  2428593    0    0 07:47:29
>
> NOTE the 07:47:XX.  All appear to have dropped at the same time.
> Hrm, one CWIX router stayed up, one went down.  CWIX, what is
> the difference?
>
>
> Chris A. Icide
> Nap.Net, L.L.C.



- - - - - - - - - - - - - - - - -