[ih] Re: IPv4 vs MAC

Bob Braden braden at ISI.EDU
Fri Jul 27 12:08:46 PDT 2001

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>From owner-ietf-outbound at ietf.org  Fri Jul 27 11:35:04 2001
Date: Fri, 27 Jul 2001 11:29:04 -0700
From: Steve Feldman <feldman at twincreeks.net>
To: Robert Elz <kre at munnari.OZ.AU>
Cc: ietf at ietf.org
Subject: Re: IPv4 vs MAC
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On Fri, Jul 27, 2001 at 03:40:53PM +0700, Robert Elz wrote:
> Does no-one else still recall the world before ARP, where MAC addresses
> (ie: the old 16 bit things that 3Mbit ethernet used) were embedded in the
> bottom 16 bits of your class B address (no-one had anything smaller than
> that of course...)

Oh my, I remember writing drivers for those beasts
back in my UC Berkeley days.  (We had a class A!)

And wondering how to deal with those new-fangled 48 bit
MAC adddresses in 10 Megabit Ethernet.  I think I
started off just taking the low 16 bits, which worked
fine when there were only 100 or so Ethernet interfaces
in existence.  (The first ARP RFC didn't come out until
after I graduated.)

As I recall, Xerox's XNS protocol used the entire MAC address
as the protocol address, which made translation easy but
routing difficult.

I feel old...


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