Both IPv4 and IPv6 Shortcuts use IS-IS as the Interior Gateway Protocol (IGP) and the link state packet (LSP) for reachability information. However, IPv4 Shortcuts use TLV 135 and IPv6 Shortcuts use TLV 236. All TLVs announced in the IS-IS LSPs are grafted onto the shortest path tree (SPT) as leaf nodes. IS-IS transports the IPv6 reachability information to remote BEBs and uses the shortest path, calculated by SPBM, for data forwarding.
Note
You only configure the IPv6 address information on the edges. There is no IPv6 in the SPBM cloud.
IS-IS transports the IPv6 routes through TLV 236 in the LSP advertisements. These routes are installed in the Global Routing Table (GRT) with the node from which the LSPs carrying the IPv6 routes are received as the next hop.