Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!mit-eddie!genrad!decvax!ucbvax!PURDUE.EDU!narten
From: narten@PURDUE.EDU
Newsgroups: comp.protocols.tcp-ip
Subject: Re: IP Datagram sizes
Message-ID: <8705270045.AA26071@gwen.cs.purdue.edu>
Date: Tue, 26-May-87 20:45:11 EDT
Article-I.D.: gwen.8705270045.AA26071
Posted: Tue May 26 20:45:11 1987
Date-Received: Sat, 30-May-87 02:16:06 EDT
References: <8705261555.AA14106@ames-nas.arpa>
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 13

It has already been pointed out that MSS negotiation can only be done
at connection set up time if one goes by the spec. One still can
dynamically adjust the MSS though, provided that the negotiated values
are high at the outset. Just because the negotiated MSS is large,
doesn't mean that segments of that size have to be sent.

In other words, negotiate a value that is too large rather than too
small, and use as large a value as gets through without fragmenting
(without exceeding the negotiated value of course). Such a scheme is
also compatible with what is currently implemented. Old TCP
implementations will negotiate small MSS's. 

Thomas