On Nov 7, 2012, at 5:33 PM, "Ole Troan (otroan)" <otr...@cisco.com> wrote: > Disagree. Hierarchical or flat PD (with relays) don't work for multihomed > sites, have problems with arbitrary topplogies etc.
You said this before, but you didn't describe any arbitrary topology in which PD wouldn't work. Could you do that, please? To be clear, although a PD topology is always hierarchical with respect to the relationship between any given requesting router and its delegating router(s), this does not mean that the topology of the homenet is a hierarchy. Let me give you an example. Suppose you have a CPE router, A, at the customer edge. And you have two homenet routers, B and C, each with an interface connected to A. And you have a fourth homenet router, D, with an interface connected to B and one connected to C (I'm assuming direct twisted-pair ethernet links for simplicity). I think you are supposing that because D has two paths to A, it will appear twice in the PD topology, even though it exists only once. But that is not so. It is only attempting to configure one interface—its downstream interface. So the DUID and IAID will be the same in both copies of the DHCP solicit that A gets. And so A will assign a single prefix, not two. Suppose D is also a edge router. We are now multihomed; A will be a requesting router with respect to D for the prefix that D got from its ISP; D will still be a requesting router with respect to A for the prefix that A got from its ISP. The relationships between B and C and A, and between B and C and D, are likewise straightforward. I can diagram this out for you if you want, but hopefully that illustrates the point I'm making. Are you thinking of an even more contorted topology than this one? _______________________________________________ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
