Dell EMC Networking OS Configuration Guide for the S5048F–ON System 9.14.2.4

Configuring Multi-Topology IS-IS (MT IS-IS)

To configure multi-topology IS-IS (MT IS-IS), use the following commands.

1. Enable multi-topology IS-IS for IPv6.
   ROUTER ISIS AF IPV6 mode
   multi-topology [transition]
   Enter the keyword transition to allow an IS-IS IPv6 user to continue to use single-topology mode while upgrading to multi-topology mode. After every router has been configured with the transition keyword, and all the routers are in MT IS-IS IPv6 mode, you can remove the transition keyword on each router.
   NOTE When you do not enable transition mode, you do not have IPv6 connectivity between routers operating in single-topology mode and routers operating in multi-topology mode.
2. Exclude this router from other router’s SPF calculations.
   ROUTER ISIS AF IPV6 mode
   set-overload-bit
3. Set the minimum interval between SPF calculations.
   ROUTER ISIS AF IPV6 mode
   spf-interval [level-l | level-2 | interval] [initial_wait_interval [second_wait_interval]]
   Use this command for IPv6 route computation only when you enable multi-topology. If using single-topology mode, to apply to both IPv4 and IPv6 route computations, use the spf-interval command in CONFIG ROUTER ISIS mode.
4. Implement a wide metric-style globally.
   ROUTER ISIS AF IPV6 mode
   isis ipv6 metric metric-value [level-1 | level-2 | level-1-2]
   To configure wide or wide transition metric style, the cost can be between 0 and 16,777,215.