On 26 Jan 2012, at 16:53, Owen DeLong wrote: > On Jan 26, 2012, at 8:14 AM, Ray Soucy wrote: > >> Does this mean we're also looking at residential allocations larger >> than a /64 as the norm? >> > > We certainly should be. I still think that /48s for residential is the right > answer. > > My /48 is working quite nicely in my house.
There seems to be a lot of discussion happening around a /60 or /56. I wouldn't assume a /48 for residential networks, or a static prefix. >> So a CPE device with a stateful firewall that accepts a prefix via >> DHCPv6-PD and makes use of SLAAC for internal network(s) is the >> foundation, correct? > > I would expect it to be a combination of SLAAC, DHCPv6, and/or DHCPv6-PD. > Which combination may be vendor dependent, but, hopefully the norm will > include support for downstream routers and possibly chosen address style > configuration (allowing the user to pick an address for their host and > configure it at the CPE) which would require DHCP support. Yes, the assumption is multi-subnet in the homenet, with a method for (efficient) prefix delegation internally. >> Then use random a ULA allocation that exists to route internally >> (sounds a lot like a site-local scope; which I never understood the >> reason we abandoned). > > I can actually see this as a reasonable use of ULA, but, I agree site-local > scope would have been a better choice. The maybe you can maybe you cant route > it nature of ULA is, IMHO it's only advantage over site-local and at the same > time the greatest likelihood that it will be misused in a variety of harmful > ways, not the least of which is to bring the brain-damage of NAT forward into > the IPv6 enterprise. Site-locals didn't include the "random" prefix element, thus increasing the chance of collision should two site-local sites communicate. See RFC3879 for the issues. >> I'm just not seeing the value in adding ULA as a requirement unless >> bundled with NPT for a multi-homed environment, especially if a >> stateful firewall is already included. If anything, it might slow >> down adoption due to increased complexity. > > I don't believe it adds visible complexity. I think it should be relatively > transparent to the end-user. > > Basically, you have one prefix for communications within the house (ULA) and > another prefix for communications outside. The prefix for external sessions > may not be stable (may change periodically for operational or German > reasons), but, the internal prefix remains stable and you can depend on it > for configuring access to (e.g. printers, etc.). > > Sure, service discovery (mDNS, et. al) should obviate the need for most such > configuration, but, there will likely always be something that doesn't quite > get SD right somehow. > > Also, the ULA addresses don't mysteriously stop working when your connection > to your ISP goes down, so, at least your LAN stuff doesn't die from ISP death. Consider also long-lived connections for example. I don't think there's a conclusion as yet in homenet about ULAs, nor will a conclusion prevent people doing as they please if they really want to. Tim
