rfc-2921
6BONE pTLA and pNLA Formats (pTLA)
This memo defines how the 6bone uses the 3FFE::/16 IPv6 address prefix, allocated in RFC 2471, "IPv6 Testing Address Allocation", to create pseudo Top-Level Aggregation Identifiers (pTLA's) and pseudo Next-Level Aggregation Identifiers (pNLA's). This memo provides information for the Internet community.