You need to subtly configure IPv6 IS-IS routing information
sometimes to meet the requirements of complex networks, implementing
accurate control on IPv6 IS-IS routing information.
If devices in an IS-IS routing domain need to learn external routes, configure IS-IS on a Level-1-2 device of this routing domain to import external routes.
This section describes how to configure Intermediate System to Intermediate System (IS-IS) to generate IPv6 default routes to control the advertising of IS-IS routing information.
To improve the route searching efficiency and simplify route management on a large-scale IS-IS network, configure IS-IS route summarization to reduce the number of IS-IS routes in a routing table.
If some ipv6 IS-IS routes are not preferred, configure conditions to filter ipv6 IS-IS routes. Only ipv6 IS-IS routes meeting the specified conditions can be added to an IPv6 routing table.