[nSLUG] Re: MAC-address/router question

Bill Davidson bdavidso at supercity.ns.ca
Fri Dec 9 09:36:40 AST 2005


On Fri, 2005-09-12 at 06:41 -0400, Dop Ganger wrote:
> Every manufacturer is given a block of address space to allocate MAC 
> addresses out of by the IEEE (see 
> http://standards.ieee.org/regauth/oui/index.shtml). Each NIC is then 
> supposed to have a unique MAC address in order to avoid collisions 

I remember years ago reading an interview in Byte magazine with one of
the developers of ethernet.  He said that one of the ideas they had
considered was to have each NIC randomly generate its own MAC address at
boot time.  They did the math and figured that, with 32 bit addresses,
the likelihood of a MAC address collision on even large networks was
essentially nil, but then they decided that people who didn't do the
math would see that as a weakness and use other technologies, so they
went with the "guaranteed unique MAC address" idea -- which you point
out isn't always so guaranteed.

Bill Davidson
bdavidso at supercity.ns.ca


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