You need to subtly configure IS-IS routing information
sometimes to meet the requirements of complex networks, implementing
accurate control on IS-IS routing information.
This section describes how to configure Intermediate System to Intermediate System (IS-IS) to generate 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 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.
If some IS-IS routes are not preferred, configure conditions to filter IS-IS routes. Only IS-IS routes meeting the specified conditions can be added to an IP routing table.