Re: [dhcwg] I-D Action: draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-00.txt

["A. Gregory Rabil" <[e-mail]>]

On Wed, Jul 11, 2012 at 4:10 PM, Ted Lemon <[e-mail]> wrote:

> Okay, great.   So, the link-layer address for the interface being
> configured is being attached to the packet that was sent on that interface,
> but somehow this doesn't satisfy your need.   Can you describe (please, one
> or two sentences, not several paragraphs) under what real-world
> circumstances this would occur?
>
>
Okay, consider prefix-delegation, for example.  The requesting router will
send an IA_PD request out the WAN interface to get a prefix which is then
allocated to the downstream/LAN interface.  Since the packet is sent via
the WAN interface, I believe that the relay would insert the link-layer
address of the WAN interface in the request, and thus the prefix would then
be "associated" with the WAN interface, whereas it is really associated
with the LAN interface.  So, this is how the interface being configured is
NOT the interface on which the packet is sent.  Further, consider a
requesting router with two distinct downstream/LAN interfaces.  The PD
requests for both LAN interfaces would be sent via the WAN interface, and
thus the WAN's link-layer address will be inserted into the option by the
relay (or learnt by the server from layer 2).  An administrator may wish to
configure different prefixes and/or options for each LAN interface, but has
no way to do identify them individually via the proposed mechanism.

Sorry, that was more than two sentences.  I hope it is a bit clearer now.

Greg