On 5 jun 2008, at 19:14, bmanning@vacation.karoshi.com wrote:
you mean longer than /64? I have built a network out of a /96, using /120's for subnets. you have to turn -off- all the autoconfig crap - but it is doable. dhcpv6 would have been a real help then.
Just make sure you don't use the all-zeros address because that's the all-routers anycast address even though many routers don't care. Nightmare scenario would be that they start caring after some update. The top 128 addresses of a subnet are reserved anycast addresses too, so /120 or longer isn't ideal either. /112 is good because then the last four hex digits are your subnet. However, you can also often just use link locals, routing protocols only use link locals, anyway.
Note that DHCPv6 will only give you address assignment (if supported by both the client and the server) but it won't give you a subnet prefix length or a default router, for this you still need router advertisements. But you REALLY don't want to use non-/64 subnets unless you manually configure them, trust me.