On Oct 20, 2014, at 2:00 PM, James Woodyatt <j...@nestlabs.com> wrote: > Okay... except it seems you're admitting that my scenario where a simple > reconfiguration of a network topology, e.g. one caused by an intermittent RF > interference on an unlicensed band of the radio spectrum, would result in a > fully regular and normalized generation of a ULA prefix that would > subsequently be deprecated on network rejoin and subsequently deprecated > again. This could happen several times per hour, right?
No, if it's done right the network would have to be partitioned for on the order of a week or two before the new ULA would be generated. >>> > Returning to my question: why do we always need a locally-generated ULA >>> > prefix? If it's to provide a time-invariant locally routable address to >>> > hosts, then locally generated ULA prefixes cannot ever be permitted to >>> > expire for any reason. If they are ever allowed to expire, then they >>> > don't provide the time-invariant property. However, if we don't actually >>> > need the time-invariant property, then what does a locally-generated ULA >>> > prefix do for us whenever one or more delegated prefixes is also present? >>> > It's not clear to me they are anything but absolutely redundant and >>> > unnecessary in that situation. >>> >> This is a bit of a straw man (see previous comment). I think trying to >> keep a permanent ULA is a good thing. We can't always succeed, but we can >> make the set of circumstances under which we fail as small as possible. >> This is in contrast to what you are proposing, which is that we essentially >> set out to fail, and see deprecation events whenever the upstream network >> goes down. >> > I certainly would agree with your observation that I don't see keeping a > permanent ULA as a good thing in itself. I keep asking why that would be > beneficial, and the answers continue to leave me scratching my head. Please > count me as one of the people here who has read Brian Carpenter's rant in > SIGCOMM about IP Addresses Considered Harmful, and who generally agrees. I'm > uncomfortable trying too hard to achieve some partial and dubious success at > establishing a persistent ULA prefix in the home network. I think we should > put our efforts more into making persistent the local namespace for service > registration and discovery. The reason I think it's beneficial is that it reduces to the minimum the number of instances where a long-lived connection will have to be broken because of a renumbering event. I don't think we can reduce that number to zero, but I think we can make it a lot less likely than it would be if we renumber every time the upstream link goes away. _______________________________________________ homenet mailing list homenet@ietf.org https://www.ietf.org/mailman/listinfo/homenet
