Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!rutgers!ames!ucbcad!ucbvax!QUABBIN.SCRC.SYMBOLICS.COM!DCP From: DCP@QUABBIN.SCRC.SYMBOLICS.COM (David C. Plummer) Newsgroups: comp.protocols.tcp-ip Subject: Re: IBM TCP. Message-ID: <870804093337.8.DCP@KOYAANISQATSI.S4CC.Symbolics.COM> Date: Tue, 4-Aug-87 09:33:00 EDT Article-I.D.: KOYAANIS.870804093337.8.DCP Posted: Tue Aug 4 09:33:00 1987 Date-Received: Thu, 6-Aug-87 01:25:35 EDT References: <12323617830.139.SY.KEN@CU20B.COLUMBIA.EDU> Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 35 Date: Mon 3 Aug 87 16:54:35-EDT From: Ken Rossman We've had a reasonable amount of experience with medium to large DECnet networks here at Columbia. We have our own internal network, and we also connect to various other sites who also have their own DECnet networks. I am not sure how Ethernet addresses are administered (I was under the impression that one or more of the larger corporations plugging Ethernet divvy up the board addresses by board manufacturer). In any case, the first four bytes of a DECnet transformed Ethernet address are, by some "global allocation" method, preassigned to DEC as I understand it. Sorry. Ethernet addresses are, in theory, assigned to hardware manufacturers in 2^24 address chunks and the manufacturer is responsible for administering its 2^24 addresses. DEC is "reassigning" the original hardware Ethernet address to be a DEC-specific protocol-related hardware address. That is not the intention of the Blue Book. DEC does not "manufacture" Interlan, 3Com, Symbolics, TI, etc, hardware, yet the hardware Ethernet addresses used would indicate DEC does. ... As for DECnet, ARP, and ethernet addresses, Ultrix handles this just fine. We just make sure that DECnet comes up before IP does, so that the ethernet address that ARP uses is the DECnet-transformed one. /Ken That's not what I meant. What I meant was that ARP existed in time for DECnet IV to use it, and that if DECnet used ARP instead of its current algorithmic translation, (a) we could preserve globally unique addresses, (b) you wouldn't have to worry about bringing up DECnet before IP (or any other protocol), and (c) if somebody else goes against the intention of the Blue Book we could still run DECnet and that other protocol at the same time (since it wouldn't then require different Ethernet addresses).