http://www.rfc-editor.org/rfc/rfc2450.txt
RFC 2450: Proposed TLA and NLA Assignment Rule, R. Hinden1998-12-01T23:00:00-00:00This document proposes rules for Top-Level Aggregation Identifiers (TLA ID) and Next-Level Aggregation Identifiers (NLA ID). This memo provides information for the Internet community.