Re: [nsp] BGP maximum datagram size

From: jlewis@lewis.org
Date: Tue Oct 30 2001 - 15:46:47 EST


On Tue, 30 Oct 2001, Stephen Sprunk wrote:

> > Also, i found in "sh ip bgp neighbor" output the following line:
> "Datagrams
> > (max data segment is 536 bytes)".
>
> Okay, TCP has for some reason negotiated a MSS of 536, which means a maximum
> datagram size of 576, assuming you're using IPv4 and there are no IP or TCP
> options present.

Other than a small MTU somewhere on or between the routers, why might they
do this? I just checked on a few routers (7513, 7206, 3640) running both
iBGP and eBGP with peers at the other ends of point to point T3's,
T1's or across our WAN. All of them show:

Datagrams (max data segment is 536 bytes):

-- 
----------------------------------------------------------------------
 Jon Lewis *jlewis@lewis.org*|  I route
 System Administrator        |  therefore you are
 Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________



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