[e2e] use of MAC addresses

[Fahad Dogar]

On 4/14/06, Joe Touch <touch at isi.edu> wrote:
>
>
> Fahad Dogar wrote:
> > On 4/13/06, Joe Touch <touch at isi.edu> wrote:
> ...
> > IMHO, we have to change these protocols because they have been
> > designed keeping in view the presence of MAC addresses and how they
> > work.
>
> You need to change the protocols only if they don't do something you
> need to do. What is it you need to do?
>
> > If we were to redesign Internet and networking technologies
> > (clean slate approach), do we need to have a different MAC address.
> > Shouldn't IP address be sufficient? It is like assigning a globally
> > unique name to every person and then asking him to maintain an
> > additional name for 'local' identification.
>
> The locally unique address is how you know you're different from someone
> else before you get (or pick a random, possibly colliding) IP address.

I think this is one very valid answer to my question.  My question was
not on whether we should do away with MAC addresses. As has been
rightly pointed out in this thread there is no need to do this ---
both from cost and efficiency point of view. I was interested in
knowing whether we can do this in 'theory' i.e. if we can identify an
interface by an IP address then in theory we should be able to reach
that interface without requiring any other form of identification.

You have right mentioned the need for another address during the phase
when the IP address is not assigned (DHCP). Any other alternative
based on (name, address) combination is effectively an alternate to
MAC address which shows that we DO need an identifier in addition to
the IP address.

Thanks,
Fahad

> The reason for that need is the MAC protocol - bridging, backoff,
> spanning tree, etc. If you design a multi-access subnet that doesn't
> need unique a-priori addresses, then you might be able to reuse IP
> addresses.
>
> I.e., this needs to be motivated at the MAC layer.
>
> Joe
>
>