Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!apple!bionet!arisia!roo!topaz!masinter From: masinter@parc.xerox.com (Larry Masinter) Newsgroups: comp.dcom.lans Subject: Re: Ethernet Vs. IEEE 802.3 ?????????? Message-ID: Date: 29 Dec 90 05:47:48 GMT References: <12710012@hpspdra.HP.COM> <3443@lectroid.sw.stratus.com> <13332@uudell.dell.com> Sender: news@parc.xerox.com Organization: Xerox PARC, Palo Alto, CA Lines: 41 In-Reply-To: mjhammel@Kepler.dell.com's message of 19 Dec 90 22:56:39 GMT >> > It's actually the other way around: 802.3 Length is in the range >> > 0-1500, while Ethernet ProtocolType has the larger values. And why be >> > so tentative about this? You certainly CAN count on it; it works; it >> > IS the way to tell the two apart. >> >> With one exception: the Xerox PUP ethernet type lies within the 802.3 >> length range (it's 0200). Fortunately, it isn't used much anymore, so >> you probably don't have to worry about it. > Someone else mentioned this to me but said that Xerox had changed (or > was going to change, maybe) the type value to one that didn't conflict. > Do you know if this is true? ================================================================ >The only "illegal" ethernet types i've ever heard of were a couple of >ancient Xerox PUP values that fell below the 1500 value. Both of them >were reallocated legal values long ago, so i wouldn't expect to see >any software using the old values. Actually, i'm not sure i'd expect >to see any software using the new values, either, since i don't >believe PUP is used much any more. Well, at the home of th PARC Universal Packet, there are still a few machines around that talk PUP. Officially reallocating packet types doesn't help much when you are dealing with software that you couldn't modify if you wanted to (who knows BCPL any more?)... The only product that shipped in any numbers and had PUP support was the Lisp machine, and it was given some kind of configuration switch/patch to switch the pup type to the reallocated new value. I'd guess that happened about '85. However, there's no telling if anybody bothered to reconfigure. I'm planning to bring up a netware server here, and it looks like we'll have to isolate it from the pup traffic by an appropriate router; at least the rumors are that the netware servers will not coexist. That's a nuisance, of course... -- Larry Masinter (masinter@parc.xerox.com) Xerox Palo Alto Research Center (PARC) 3333 Coyote Hill Road; Palo Alto, CA USA 94304 Fax: (415) 494-4333