22 May
2000
22 May
'00
4:46 p.m.
Architecturally, IPv6 has the equivalent of variable length subnet masks built in. There are really only two boundaries that are not flexible- the boundary between the format prefix and the rest of the address, and the /64 boundary. (The format prefix is in fact variable length, but it is architecturally defined.) So any IGP or EGP design needs to be fully flexible to the left of /64. Subnetting to the right of /64 would be tricky.
all IGP's and EGP's have to support all prefix-lengths. e.g you want to announce host routes, /96 for NAT-PT, etc. for that matter, the implementation(s) I know will let you create subnets of whatever size you like. /ot