Path: utzoo!utgpu!watmath!clyde!bellcore!rutgers!mailrus!nrl-cmf!ames!pasteur!ucbvax!spider.co.UK!nick
From: nick@spider.co.UK (Nick Felisiak)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Running out of Internet addresses?
Message-ID: <8812081610.AA09360@redrump.spider.co.uk>
Date: 8 Dec 88 22:50:12 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 23
X-Unparsable-Date: Thu, 8 Dec 88 16:10:03 WET DST

In message [A.ISI.EDU]28-Nov-88 18:47:32.CERF, Vint Cerf writes:
> 
> New versions of anything are always tricky. I'd like to hear from
> some LAN analyzer vendors how they feel about variable versus
> fixed length addressing; ditto the IP and TCP level programmers.
>
> [...]
> 
> Vint
> 

We decode TCP-IP headers in the Spidermonitor.  Handling variable length
decodes is not in itself a problem.  The hard part is setting up filtering
criteria based on variable length stuff.  It is difficult to present
the user with an easy to use template which will cope with a variable length
field, and to have the time critical code which accepts or rejects packets
do enough decode to find the right field before comparing it.

Consequently, using the Decnet template, the user gets less help in setting
up a trace, although the packets are correctly decoded when displayed.

Nick Felisiak			nick@spider.co.uk
Spider Systems Ltd