[opendtv] Re: Twang's Tuesday Tribune (Mark's Monday Memo)
- From: Craig Birkmaier <craig@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Tue, 4 May 2004 14:58:26 -0400
At 10:22 AM -0700 5/4/04, Kon Wilms wrote:
> >I can understand how this could happen because of poor control of
>addresses by a manufacturer. What I cannot understand is how two
>devices located anywhere in the world can share the same MAC address.
>
>Actually it is quite easy. Of the 6 bytes in a mac address, the first 3
>represent the manufacturer id. The manufacturer must randomize the last 3
>for device rollout. With a range of 3 bytes, there is bound to be
>duplication (you can't even roll out a decent amount of receivers without
>using up every number). Many manufacturers cut corners in manufacturing and
>use a random number generator but do not check against a known list of ids
>previously created.
>
>Plus, you can change the MAC address on most boards (datacast receivers are
>notorious for allowing you to do this).
>
>So its not so useful for targeting or ensuring data only reaches one
recipient.
Thanks!
Doesn't IPV6 deal with these shortcomings?
Regards
Craig
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