Dell PowerEdge FN I/O Module Configuration Guide 9.10(0.0)

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.