Displaying the IPv6 unicast FIB

Use the following procedure to display the IPv6 unicast Forwarding Information Base (FIB). The tab shows IPv6 routes from remote Backbone Edge Bridges (BEBs)

In SPBM, each node has a System ID, which also serves as Backbone MAC address (B-MAC) of the switch. These Backbone MAC addresses are populated into the SPBM VLAN Forwarding Information Base (FIB). When the network topology is discovered and stored in the IS-IS link-state database, each node calculates shortest path trees for each source node, so that a unicast path now exists from every node to every other node. With this information, each node populates unicast information received from SPBM into the FIB for forwarding purposes.

I-SIDs are only used for virtual services (Layer 2 VSNs and Layer 3 VSNs). If you only enable IP Shortcuts on the Backbone Edge Bridges, I-SIDs are never exchanged in the network as IP Shortcuts allows for Global Routing Table (GRT) IP networks to be transported across IS-IS.