Hi Suresh, Suresh Krishnan wrote: > > Hi Julien, > > On 10-09-08 07:43 PM, Laganier, Julien wrote: > > Thomas Narten wrote: > >> [...] > >> > >> RAs/SLAAC work very well when RAs can be multicast to *all* nodes on > >> a link, and *all* nodes receive exactly the same information about > >> prefixes and SLAAC. I.e, your normal subnet model. > >> > >> What BBF is proposing to do, is to use RAs/SLAAC where each customer > >> node (i.e, each node on the access network) recieves *different* > >> configuration information. This means that multicast model on which > >> RAs were built doesn't work. > >> > >> This is hardly a "normal" IPv4 subnet model even. (I.e., the nodes > >> don't share a common prefix, even though they are in the same > >> broadcast domain.) > > > > Right, what we essentially have here (and what has been referred to > > as "N:1 VLAN allocation model") is a point-to-multipoint link model > > that constitutes a broadcast domain but where there is a desire to > > advertize different prefixes to different endpoints (CPEs at the > > multipoint end.) > > > > The 16ng WG has managed to do so something similar over the IEEE > > 802.16 link layer that is documented in RFC 5121. In 16ng however, from > > the perspective of the edge router, each of branch of the point-to- > > multipoint 802.16 link layer appears as a distinct link to the IP layer, > > thanks to the use of distinct, per-endpoint, IEEE 802.16 connection IDs > > and tunneling between the edge router and the aggregation point. > > Because there is a different link between the edge router and the > > endpoints, the edge router can multicast unsolicited RAs containing a > > per-endpoint prefix on each of the links. > > > > In BBF this cannot be done because there is no tunneling between the > > access node and the edge router, and thus the edge routers sees only > > one link. > > > > Maybe it is time to write an "Issues with Per-Endpoint Subnet Link > > Model on Point-to-Multipoint Links" that would explains the caveats > > that exists, ala RFC 4903. > > This sounds like a good idea. I think identifying the generic issues > with this kind of usage will be invaluable. I am looking forward to > read and contribute.
I will give it a try. I have spent a fair amount of time working on this in the early days of the NETLMM WG while trying to support shared links where each mobile node configure an address in a different prefix. --julien -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
