[e2e] use of MAC addresses

John Day day at std.com
Tue Apr 18 14:38:55 PDT 2006


You know Dave, you really should get better at noticing when one's 
tongue is in one's cheek.  ;-)


At 17:26 -0400 2006/04/18, David P. Reed wrote:
>John Day wrote:
>>I have always thought it peculiar that MAC addresses had a larger 
>>address space than IP addresses.
>Yup, we have always known that IP address space was too small to be 
>correct.  To be specific, we includes, without being limited to, 
>Xerox PARC and the Saltzer, Clark, Reed group at MIT.
>>This confusion of IEEE 802 universal serial numbers with addresses 
>>always seemed a little strange to me.
>This goes back to Xerox PARC, whose researchers recognized the very 
>low cost and very high value of guaranteed unique identifiers as the 
>base name space for networking, given the fact that networks are 
>transient collections of devices, so binding naming to the 
>particular topology merely made the system architecture more complex 
>than necessary.
>
>A simple way to realized that this is not strange is that the 
>integers are the same mathematical objects, no matter whether you 
>choose to represent them in decimal, hex or floating point ternary. 
>Same with endpoints.  They are the same no matter what network they 
>are temporarily attached to.
>
>Only people who thought that the wires and topology are more 
>conceptually important than the endpoints would have decided that 
>mobility was of such little importance that they would bind 
>addressing to topological happenstance.  In other words, in IP, the 
>"routerheads" won - rather than the "internetworkers".
>
>
>48-bits was chosen by the Xerox-DEC-Intel group as a compromise. 
>Most of us researchers were convinced that 64 bits would have been 
>more easily allocated.



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