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