host-identifier with IPv6

[Frank Sweetser]

David W. Hankins wrote:
> On Mon, Mar 02, 2009 at 09:32:27PM -0500, Frank Sweetser wrote:
>> Would it be feasible to define behavior where the circuit-id, or some other 
>> field with similar behavior, contained the client HW address?
> 
> In DHCPv4 we've had no end of problems because of standards text that
> touches into the IP and link layer headers (all-ones limited
> broadcast).
> 
> So it would be my vast preference to maintain a setup where raw
> packets aren't required.  I think this means the client supplies the
> MAC address as an option inside its IA_*'s, as part of any "final"
> solution.

Okay, I'll keep this in mind on that draft that I mentioned many emails ago. 
Do you have any suggestions for exactly how the client MAC should be added to 
the IA?

> An alternative interim solution in that area would be to use the
> client's link local address as it was perceived by the relay agent (or
> by the server directly).  Relays and servers already record this so
> they know where to direct the replies.

There's obviously some subtlety I'm missing, because that's about what I 
thought I was proposing =)  But anyway, yes, that certainly sounds like an 
acceptable solution to me.

It sounds like one minor downside would be that, at least at first, this 
workaround would be specific to the ISC relay agent, so it wouldn't be 
available in existing router based relay agents, requiring that a server be 
installed on each IPv6 VLAN.  Our current core routers don't have a v6 relay 
agent, though, so not only would we already have to do that, but we'd also be 
in a good position to request that vendor implement the same interim solution 
that the ISC one does.

Even for people who already have v6 relay agents they wouldn't be able to use 
this scheme with, it would still be far, far less work than attempting to 
manage any kind of client based solution.

-- 
Frank Sweetser fs at wpi.edu  |  For every problem, there is a solution that
WPI Senior Network Engineer   |  is simple, elegant, and wrong. - HL Mencken
     GPG fingerprint = 6174 1257 129E 0D21 D8D4  E8A3 8E39 29E3 E2E8 8CEC