Excuse me while I delurk for a moment.
From: "Jeroen Massar" <jeroen@unfix.org>
From draft-ietf-ipngwg-addr-arch-v3-11.txt: 8<-------------------------------- 2.5.4 Global Unicast Addresses
The general format for IPv6 global unicast addresses is as follows:
| n bits | m bits | 128-n-m bits | +------------------------+-----------+----------------------------+ | global routing prefix | subnet ID | interface ID | +------------------------+-----------+----------------------------+ -------------------------------->8
On my reading of the I-D the "global routing prefix" described above is not the prefix that appears in the default-free zone - the text in section 2.5 suggests that, as with IPv4 CIDR, different parts of the network will have different ideas about where the boundaries are within the prefix and the text immediately following that diagram says: ... the global routing prefix is a (typically hierarchically- structured) value assigned to a site (a cluster of subnets/links), the subnet ID is an identifier of a link within the site ... That suggests the "global routing prefix" shown above is the prefix a site and its immediate upstream know about but it could, at least in theory, be further aggregated between there and the default-free zone. Is that right or have I missed something obvious? Sam Wilson Infrastructure Services Division Computing Services, The University of Edinburgh Edinburgh, Scotland, UK