Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!BBN.COM!brescia
From: brescia@BBN.COM (Mike Brescia)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: EGP and C-30s
Message-ID: <8906110223.AA01933@ucbvax.Berkeley.EDU>
Date: 2 Jun 89 20:25:44 GMT
References: <12498725722.17.AFDDN.BEACH@GUNTER-ADAM.AF.MIL>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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     We're installing cisco MGS gateways at different sites on Milnet and 
     occasionally a problem crops up with exchanging EGP updates with the
     "new" core buttergates.  Essentially there seems to be an infinite 
     cycling up and down between the gateways with the core never sending an 
     update.

     A brief example of the exchanges follows.  Our gateway is sending updates
     and the real interesting part of it is that if the PSN our gateway is
     on gets reset, the problem clears up immediately.

     *******

     This gones on until the PSN (C-30) is reset, at which point updates from
     the core begin coming in.
     ... nothing except resetting the PSN seems tp work.
     -------

Darrel,

This sounds like an X.25 type of problem, involving x.25 window size, x.25
packet size, and resources in the local PSN.  I recall a similar problem where
a system could not get an egp update through when using a packet size of 128
and a window of 2.  Try to get the packet size to 512 or 1024, and the window
size 7 (or at least 4 for 1024 byte packets).  Note that the EGP update is
sent as 3 1004 byte IP fragments (oh, well, the 3rd is shorter, but it's
growing).  The total IP datagram size is around 2800 to 2900 bytes.

Also, make sure you have assurance from Cisco that you have latest revision of
code.

Please send further notes to "gw-fire@bbn.com" if appears to be a core
gateway problem instead of a host-psn interconnect problem.

Regards,
Mike Brescia