Xref: utzoo comp.dcom.lans:5429 comp.protocols.tcp-ip:12169 Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!decwrl!sgi!rpw3@rigden.wpd.sgi.com From: rpw3@rigden.wpd.sgi.com (Rob Warnock) Newsgroups: comp.dcom.lans,comp.protocols.tcp-ip Subject: Re: Zero manufacturer code in SNAP? Message-ID: <64420@sgi.sgi.com> Date: 18 Jul 90 08:02:20 GMT References: <1990Jul17.010234.12077@portia.Stanford.EDU> Sender: rpw3@rigden.wpd.sgi.com Reply-To: rpw3@sgi.com (Rob Warnock) Distribution: na Organization: Silicon Graphics, Inc., Mountain View, CA Lines: 47 morgan@jessica.stanford.edu (RL "Bob" Morgan) writes: +--------------- | The question is, has the all-zeros SNAP id been assigned by IEEE to DoD, | or the IAB, or some IP authority, to be administered by that authority? +--------------- My understanding, which has no more authority in this case than "urban legend" (and should probably be taken with the same degree of confidence), is that the 24-bit "organization" identifier was not originally intended to be identical with the upper 24 (well, 23) bits of some assigned MAC address, but was to be a separate space assigned/managed by IEEE. (The obvious hack of making it be the same as a manufacturer's 23-bit unique MAC-address prefix came later, if at all. [*Is* that the way the IEEE assigns them?] After all, it *is* possible that a manufacturer could make more than 2^24 network interfaces and need some more addresses, so why mix SNAP IDs with MAC addresses?) So organizations had to request/register SNAP "organization IDs", and Xerox Corporation [who at Xerox?] asked for(?) / was assigned(?) [by whom?] the zero code. Xerox then said to the world, "We hereby state that we're going to use the Xerox-registered Ethernet types..." [remember that Xerox still has the registry for *Ethernet* type codes] "...in the 16-bit reserved-for-org- anization field of SNAP organization code #0 (== Xerox), and we invite any and all to do likewise". And so at an after-dinner session at the Monterey TCP/IP Conference [the First, or maybe Zero-th, Interop Conference], the "TCP/IP community" [the people in that room, at least] agreed to cease using the LSAP code that had been assigned by IEEE for IP, and agreed to use SNAP Org. Code 0 + EtherType on 802.2 links and FDDI, in order to have not only IP but ARP and BOOTP and RARP, etc. [The term "SNAPpy Xerox" was sometimes used as an irreverant handle for this encoding, until RFC-1042 came out.] Anyway, that's the way I heard it. I invite correction/historical_revision by any who have more authoritative sources/memories. [Won't take much to be more authoritative than the above... ;-} ] -Rob ----- Rob Warnock, MS-9U/510 rpw3@sgi.com rpw3@pei.com Silicon Graphics, Inc. (415)335-1673 Protocol Engines, Inc. 2011 N. Shoreline Blvd. Mountain View, CA 94039-7311