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

[Tiago Camilo <tandre@dei.uc.pt>]

Hi Chip,
Thanks for your reply,
Can you inform me who are the people involved in the snooping issue? We are
concerning about scalabilities problems..
Thank once again,
Tiago Camilo



Quoting "Chip Popoviciu (cpopovic)" <cpopovic@cisco.com>:

> 
> Hello Tiago,
> 
> The document discussed the options available today and points out gaps
> that should be further addressed in other work. Solutions to the DHCP-PD
> problem are being worked on and snooping is one of them.
> 
> Regarding the text comment, I think it is just a matter of context and
> terminology. In the context and terminology of the three models
> described, the Edge router is the Layer 3 next hop for the customers. In
> the LAA model for example there are indeed multiple routers between the
> first (access) router and the Edge Router but all of them transport the
> customer traffic encapsulated and do not handle it at Layer 3. Despite
> all these routers (that are part of the NAP infrastructure), as far as
> the customer is concerned, its Layer 3 next hop is the Edge Router.
> 
> In the case of a snooping based implementation, only customer's Layer 3
> first hop router (be it the IP enabled DSLAM, the BRAS or the ER
> depending on the service model) will have to support the snooping
> feature. This router has to learn from the snooped DHCP packets what
> static routes it should install for the prefixes that were delegated to
> the customer connected to it (directly on an interface or virtually over
> PPPoE+L2TP for example), the rest of the network will learn from this
> router (through the redistribution of the static routes in a IGP) how to
> get to the delegated prefixes.
> 
> I hope this answers your questions.
> 
> Best Regards,
> Chip
> 
> -----Original Message-----
> From: owner-v6ops@ops.ietf.org [mailto:owner-v6ops@ops.ietf.org] On
> Behalf Of Tiago Camilo
> Sent: Wednesday, July 20, 2005 7:41 AM
> To: v6ops@ops.ietf.org
> Subject: draft-ietf-v6ops-bb-deployment-scenarios(if DHCP-PD server is
> not the first router outside of the customer premises??)
> 
> 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
>