rfc-3359
Reserved Type, Length and Value (TLV) Codepoints in Intermediate System to Intermediate System
This draft describes implementation codepoints within
IS-IS [ISO90 , Cal90a , Cal90b ] used today by several ISPs for
routing within their clouds. IS-IS is an interior gateway routing
protocol developed originally by OSI and used with IP extensions as
IGP. This draft summarizes all TLV codepoints that are being used by
the protocol and its pending extensions.