Multi-Topology IS-IS (MT-ISIS) support within SR OS allows for the creation of different topologies within IS-IS that contribute routes to specific route tables for IPv4 unicast, IPv6 unicast, IPv4 multicast, and IPv6 multicast. This capability allows for non-congruent topologies between these different routing tables. As a result, networks are able to control which links or nodes are to be used for forwarding different types of traffic.
For example, MT-ISIS could allow all links to carry IPv4 traffic, while only a subset of links can also carry IPv6 traffic.
SR OS supports the following multi-topologies:
IPv4 Unicast – MT-ID 0
IPv6 Unicast – MT-ID 2
IPv4 Multicast – MT-ID 3
IPv6 Multicast – MT-ID 4