Hi!

Here is what I think. Yes, it is true that if the
manufacturer has not made mistakes, the MAC address is
unique. However, lets consider the following scenario.

Coincidently, a user on the foreign network has
manually configured an address that happens to be the
address which you are suppose to configure when you
reach the foreign network. In that scenario, you have
a conflict.

The odds of having a conflict are minimal. If i am not
mistaken, an authority in MIPv6 mentioned that the
odds are 1 in a billion. However, if intentionally
done to harm someone, the odds might become great :).

In another scenario, lets say you have registered your
address with your home agent, then suddenly there is a
power failure on your machine or something. Your
machine gets terminated abruptly therefore, the
binding is still present in the home agent. When your
machine comes up and it tries to register the same
address which it had before, then there is a conflict.

On the same note, MIPL does allow optimistic handoff,
where there is no need to perform DAD.

rgds,
Shariq
--- [EMAIL PROTECTED] wrote:

> 
> Hello 
> 
> I have got some basic questions regarding the need
> to perform DAD and a confirmation would be
> appreciated
> 
> Obviously DAD is performed to check the uniqueness
> of the auto-configured data, but since the
> auto-configured address is formed by appending the
> prefix advertised by RA with the MAC address of the
> interface, and since MAC addresses are globally
> unique then why perfom DAD?
> 
> For example when a MN moves to a visit net, then if
> for example if the MAC address is AA:BB:CC:DD:EE:FF
> and the advertised prefix was 2001:001b::1/64 then
> the newly autoconfigured address would be 
> 2001:001b:0:1:AABB:CCFF:FEDD:EEFF.
> Am I correct? If i am then under what circumstances
> can this address have a conflict with any other node
> on the new link as the MAC address is globally
> unique???
> 
> A reply is eagerly awaited
> 
> ZFaqeer
> 
> 
> 
> 
>
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