Reed's views, was [e2e] Cannara's views

John Kristoff jtk at
Mon Apr 16 16:13:44 PDT 2001

John Day wrote:
> In fact, even Ethernet reflects the state of our understanding at the
> time.  Then we didn't understand that addresses only had to have the
> scope of the layer in which they were used.  I really doubt that
> there will ever be an Ethernet segment or even a bridged ethernet
> with 2**48 devices or anything remotely close to it.  16 bits would
> have been more than enough.  What is interesting is that IEEE 802
> still hasn't figured it out.  Look at firewire addresses.

I was still learning how to dress myself while all this stuff was going
on, but reading into what Seifert in his "The Switch Book" says, the
thought about the 48-bit address space was done more for administrative
purposes than for the purpose of actually needing that many addressable
stations on a single data link.  An excerpt:

"... the Ethernet designers consciously took a different approach to
Data Link layer addressing.  Rather than trying to save transmission
overhead by conserving bits, we instead opted to create a huge address
space capable of providing a globally-unique Data-Link address to every
device for all time.  The Ethernet address space was designed to allow a
unique address to be permanently assigned to every device that would
ever attach to a LAN."


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