Re: IPv6 Interview Questions and critic

[Eric Gauthier <eric () roxanne org>]

Joe,

> Ipv6 uses 128 bits to provide addressing, routing and identification
> information on a computer. The 128-bits are divided into the left-64 and
> the right-64.  Ipv6 uses the right 64 bits to store an IEEE defined global
> identifier (EUI64). This identifier is composed of company id value
> assigned to a manufacturer by the IEEE Registration Authority. The 64-bit
> identifier is a concatenation of the 24-bit company_id value and a 40-bit
> extension identifier assigned by the organization with that company_id
> assignment. The 48-bit MAC address of your network interface card is also
> used to make up the EUI64.

I'm definitely not an expert, but my understanding is that the left 64
bits are structured as a EUI64 "address" but are not REQUIRED to be
your systems MAC address.  By default, your system may choose to populate
the bits with your MAC, but your system code also choose to populate
it with something else.  This gets around privacy issues (i.e. CNN
being able to track my travel habits by watching their web server access
logs) but it does pose some interesting issues for filtering at an Enterprise
which wants to give certain levels of access to certain people.         

You might want to pose your question to one of the IPv6 mailing lists -
either 6bone () ISI EDU or users () ipv6 org.

Eric :)