Intermediate System to Intermediate System for IPv6
ISIS is one of the important Link-State protocols. With entrence of IPv6 to the network world, ISIS also need to uptade itself for this new Routed protocol. So, ISIS for IPv6 is developed.
Basically, ISIS for IPv6 is similar to previous version of ISIS, before this enhancement. But in this enhanced version of ISIS, there are some differences for IPv6 support. In this article, we ll focus on these extensions.
Let’s see the import extensions of IPv6 one by one.
IPv6 Address Support
ISIS for IPv6 is the enhanced version of ISIS, that support IPv6 routing. With ISIS for IPv6 enhancements, ISIS advertise both IPv6 prefixes and the previous IPv4 and OSI prefixes. In the previous version of ISIS, only IPv4 and OSI prefixes were being advetised.
Basically, address families supported by ISIS is increased with this ISIS for IPv6 enhancements.
Multi-Topology Extension of ISIS
Formerly, ISIS uses the same topology for both IPv4 and IPv6. It assume that all the routers in the topology must support both IPv4 and IPv6. With single topology, a single SFP per level were used for both IPv4 and IPv6. The configurations of the routes might be done for both of these protocols.