Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!cs.mu.OZ.AU!kre From: kre@cs.mu.OZ.AU (Robert Elz) Newsgroups: comp.protocols.appletalk Subject: Re: Phase 1 vs. Phase 2 Message-ID: Date: 19 Jan 91 04:48:09 GMT References: <1991Jan17.205340.11378@pbs.org> <48241@apple.Apple.COM> Sender: news@cs.mu.oz.au Lines: 56 hayes@Apple.COM (Jim Hayes) writes: >Some of the technical benefits: > Zone-wide broadcasts use multicast addresses. This is probably the number one benefit of Phase 2, the huge number of broadcasts bothering all of the ethernet hosts you have which don't give a damn about appletalk are gone in phase 2. > RTMP now uses Split-Horizon updates This is also (obviously) good, but works just as well with Phase 1... > RTMP now uses "reverse poisoning" This is good too - but you only see the effect if you have networks coming and going a lot. The nature of most appletalk nets that exist, and the general quality of the routers used (almost no-one uses hosts to route appletalk) means that in practice this is probably a small benefit. > NBP uses zone-wide broadcasts to resolve names and adds more > wildcarding features The first was always true, I suspect you mean that nbp "broadcasts" are now restricted multicasts (ie: not even all appletalk devices on the cable receive them), so devices in other zones normally need not be bothered handling a lookup that cannot succeed. The extra wildcarding is close to useless, as you can't rely on it being supported by anyone (try hunting for =Writer sometime, where by '=' I mean the 0xC5 character (approx equals) - see how many LaserWriter and ImageWriter devices respond...). > The addressing scheme suports >65300 networks Which is actually less than phase 1 allowed. > (actually 254 hosts per net > number, but you can have multiple net numbers per each wire.) The much touted "need" for phase 2, and most often trumpeted in the marketing, but actually probably the least useful of the enhancements, and just about the biggest problem (caused the most changes). This benefits only people stuck with huge bridged ethernets, which is a position they'd be better off getting out of, than attempting to get more protocols to support. > The addressing scheme supports multiple Zone names for each network. This is undoubtably useful too, but only applies to 'extended' nets. That is: ethernet & token-rings - try giving more than one zone to your localtalk because you've moved a printer to it that used to be in a different zone and you're in for a shock. kre