Subject: draft-ietf-v6ops-bb-deployment-scenarios(if DHCP-PD server is not the first router outside of the customer premises??)

From: Tiago Camilo <[email-masked]>
Date: Wed, 20 Jul 2005 12:41:21 +0100

Hi,
I have being following the design of the
draft-ietf-v6ops-bb-deployment-scenarios, and more closely with the Broadband
DSL Networks. And my doubt is concerning the DHCP-PD functionality in
intermediate L3 nodes.
As the author says:

B. Currently the DHCP-PD functionality cannot be implemented if the DHCP-PD
server is not the Edge Router. If the DHCP-PD messages are relayed, the Edge
Router does not have a mechanism to learn the assigned prefixes and thus
install the proper routes to make that prefix reachable. [...]

Does this issue is already cover, I mean does a new solution rather than
snooping is already proposed?

I also agreed with the comment of Pekka Savola, when he says that:

==> shouldn't you say something like "the first router outside of the customer
premises" instead of Edge Router? (or something a bit more
compact.) 

In a Wholesale IP model, it is possible to have several L3 devices between the
first router outside customer premises and the DHCP server. 
For instance if we consider that the DSLAM is IP enable, than it needs to be a
DHCP-PD relay agent (if the DHCP server is on NSP). My question is, do we need
to implement snooping mechanisms in DSLAM, so that this device could install
the proper routes? What about the following nodes, the BRAS and the ER, does
they need to be also DHCP relay Agents, and each one with its own snooping
mechanism?

 Customer Premise              NAP                    NSP
|---------------| |----------------------| |----------------|
                                                   +-------+
                                                   |  DHCP |
                                              +----+ Server|
                                              |    +-------+
                                              |             |
+----------+    +--------+ +----+-----+ +-----+-----+
|CPE Router+----+ DSLAM  +-+  BRAS    +-+   Edge    |
+----------+    +--------+ +----------+ |  Router   +
                                        +-----------+
                |----------------------------------------|
                                   IP

Thanks,
And best regards,
Tiago Camilo
University of Coimbra