Hi, On 10/12/11 8:38 AM, Michael Richardson wrote: >>>>>> "Russ" == Russ White <ru...@riw.us> writes: > Russ> You need a unique identifier at the equipment level for > Russ> anything you intend to auto-configure --autoconfiguring > Russ> uniqueness is a very hard, probably impossible, problem on a > Russ> global scale. So we need to count on this one thing, no matter > Russ> what else we might need to back in to. > > Russ> Now, it might be possible to some hash over a GPS location for > Russ> a "base," and then add on MAC addresses, or some such, but > > We've assumed a unique MAC, which is 48 bits long. > But OSPF router-id is 32 bits. What is the likelyhood of a collision > in the bottom 32-bits of the MAC? It seems to me that this discussion about duplicate addresses / unique MAC tool already place in the IETF a number of years ago, e.g. as reflected in RFC 4862 (IPv6 Stateless Autoconfiguration, section 5.4), where duplicate address detection is mandatory. It wouldn't have to be if the assumption holds that all MAC addresses are unique.
Even though the probability of collisions may be low, because of manufacturer errors / virtual interfaces and virtual machines / reduction from 48bits to 32bits, there could be collisions. I am not convinced that we can make Russ' assumption that we need unique identifiers at equipment level (or at least that seems inconsistent with previous IETF decisions, so we would need to make a strong case what has changed since then). I do agree with Russ, though, that verifying uniqueness is hard. Regards Ulrich _______________________________________________ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
