HP VPN Firewall Appliances Appendix Protocol Reference

53
IPv6 IS-IS
The term "router" in this document refers to both routers and routing-capable firewalls and firewall
modules.
Overview
Intermediate System-to-Intermediate System (IS-IS) supports multiple network protocols, including IPv6. To
support IPv6, the IETF added two type-length-values (TLVs) and a new network layer protocol identifier
(NLPID).
The two TLVs are as follows:
• IPv6 Reachability—Contains routing prefix and metric information to describe network reachability
and has a type value of 236 (0xEC).
• IPv6 Interface Address—Same as the "IP Interface Address" TLV in IPv4 ISIS, except that the 32-bit
IPv4 address is translated to the 128-bit IPv6 address.
The NLPID is an 8-bit field that identifies which network layer protocol is supported. For IPv6, the NLPID
is 142 (0x8E), which must be carried in hello packets sent by a router that supports IPv6 IS-IS.