nanog mailing list archives

Re: <Keepalives are temporarily in throttle due to closed TCP window>


From: Mikael Abrahamsson <swmike () swm pp se>
Date: Mon, 14 Sep 2009 19:39:12 +0200 (CEST)

On Mon, 14 Sep 2009, Michael Ruiz wrote:

I am having difficulty maintaining my BGP session from my 6509 with
Sup-7203bxls to a 7206 VXR NPE-400.  The session bounces every 3
minutes.  I do have other IBGP sessions that are established with no
problems, however, this is the only IBGP peer that is bouncing
regularly.

What does exactly the message mean and how do I stabilize this?  Any
help will be appreciated.

This is most likely an MTU problem. Your SYN/SYN+ACK goes thru, but then the first fullsize MSS packet is sent, and it's not getting to the destination. 3 minutes is the dead timer for keepalives, which are not getting thru either because of the stalled TCP session.

--
Mikael Abrahamsson    email: swmike () swm pp se


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