Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!sgi!vjs
From: vjs@rhyolite.SGI.COM (Vernon Schryver)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: 802 (.2).3 TCP/IP
Summary: yes, but how to make it work anyway?
Keywords: interoperability?
Message-ID: <14933@sgi.SGI.COM>
Date: 16 May 88 19:03:24 GMT
References: <1919@ssc-vax.UUCP> <1080@thumper.bellcore.com>
Sender: daemon@sgi.SGI.COM
Distribution: na
Organization: Silicon Graphics Inc, Mountain View, CA
Lines: 31

In article <1080@thumper.bellcore.com>, karn@thumper.bellcore.com (Phil R. Karn) writes:
> I see only one easy answer to the gratuitous compatibility problems
> imposed by 802.3: IGNORE IT!  ...

Yes, but...some vendors are already supporting it.  I'm told by some of
our customers that Gould/SEL machines can do either 'Ethernet 1 or
802.3' (meaning either lengths or types), depending on boot-time
configuration, and cannot send even raw ethernet packets of one kind
when configured for the other.  I've heard more distressing claims
about WIN/TCP for HP-3000's.  This may not be true about either (it's
only our customers beating up on us, demanding interoperability), but it
will no doubt eventually be true of some machines.

It's likely we, at SGI, can figure out how to make our drivers hear
either the old form or RFC-1042.  What should we do for output?
    -Add an option to ifconfig which tells the driver to speak RFC-1042?
    -A per-driver, system configuration option?
    -Some kind of hack for ARP like that for trailers?  Send both kinds 
	of ARP request and guess out what each destination wants by what
	you get back?  But that makes the MTU for the link kind of variable.
	It might be confusing when two such machines talk to each
	other--depending on timing, they might get different conclusions
	about each other.  What about proxy-ARP?

It might be nice if the 4.3bsd compatible vendors could be consistent.

If the problem has been solved, please forgive me, and tell me the
solution.

Vernon Schryver
Silicon Graphics
vjs@sgi.com   or   {pyramid,decwrl,research,allegra,adobe,sun}!sgi!vjs