http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1_c/1cprt1/1cisis.htm#4552.
RFC 2966, "Domain-wide Prefix Distribution with Two-Level IS-IS." Li, Tony, Przygienda, Tony, Smit, Henk.
draft-ietf-isis-hmac-00.txt: IS-IS HMAC-MD5 Authentication.
draft-ietf-isis-traffic-02.txt: IS-IS extensions for Traffic Engineering.