Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!ig!bionet!agate!ucbvax!VENERA.ISI.EDU!braden
From: braden@VENERA.ISI.EDU
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  fragmenting broadcasts
Message-ID: <8905041715.AA00694@braden.isi.edu>
Date: 4 May 89 17:15:25 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 23

Dave,

I think there is probably a bug in the current wording in Section 3.3.3
of the Host Requirements RFC on fragmentation.  It was not meant to
outlaw intentional IP fragmentation in the source host -- but it certainly
did mean to DISCOURAGE it!

I gather your application will be used ONLY across a single Ethernet, with no
gateway hops, in an environment which is sufficiently constrained that
you assume reliable delivery from the link layer.  You're sure no site
will ever try to run it through a gateway (leading to congestive losses).
There is an enormous amount of experience that such ideal enironments
don't last; customers want to use the fact that these are INTERNET
protocols, and your assumptions collapse into a "puddle of glup."
You then discover you have to provide some reliable delivery in the
application, in which case the fragmentation/reassembly needs to be
in the same layer, or performance becomes terrible.

The Host Requirements Working Group would welcome your input on the
wording of the section you are concerned with.  Our mailing list is
ietf-hosts@nnsc.nsf.net.

Bob Braden