IS-IS multi-topology (MT) allows separate topologies for IPv4 and IPv6, enabling independent shortest path (SPF) computations for each address family. While MT provides flexibility, some deployments may seek to migrate from multi-topology to single-topology mode to reduce resource consumption from redundant SPF computations.

The IS-IS BFD TLV feature implements RFC 6213. When this feature is enabled, IS-IS will prevent adjacency establishment on a link if the BFD peering is down.

The IS-IS BFD Damping feature allows IS-IS to delay adjacency establishment on a link that experiences frequent BFD flaps.