* Ray Soucy:
Every time I see this question it' usually related to a fundamental misunderstanding of IPv6 and the attempt to apply v4 logic to v6.
True, you have to ignore more than a decade of IPv4 protocol development and resort to things like pre-VLSM networking.
That said. Any size prefix will likely work and is even permitted by the RFC.
Could you quote chapter and verse, please? RFC 4291 section 2.5.4 says this: All Global Unicast addresses other than those that start with binary 000 have a 64-bit interface ID field (i.e., n + m = 64), formatted as described in Section 2.5.1. -- Florian Weimer <fweimer@bfk.de> BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99