SURFnet received an official IPv6 prefix from the RIPE NCC in August 1999 of length /35, which was enlarged to a /32 during the summer of 2002:

                                                                                   2001:0610::/321

This prefix is split up as follows:

Only the first /35 is currently used. The other 7 /35s are for future use right now. For each PoP a /40 prefix (NLA 1) is reserved and each /40 is again split into 256 /48 prefixes (NLA 2) to number the backbone links and customer networks. The breakdown of SURFnet’s prefix on a per-PoP basis is shown in detail below.

The prefix 2001:0610::/40 is in use as the carrier network for SURFnet5, in which all links reside. For the links SURFnet uses /64 prefixes, in the format:

2001:0610:00xx:xyyy::zzz

In this format, xxx denotes the third octet of the link’s or LAN’s IPv4 prefix and yyy denotes the fourth octet of the link’s or LAN’s IPv4 prefix. The zzz denotes the actual address. An example of this is shown below in Table 12-11.