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.
Only routes in an IP routing table can be used to forward IP packets. An IS-IS route can take effect only after this IS-IS route has been successfully added to an IP routing table.
If an IS-IS route does not need to be added to a routing table, specify conditions, such as a basic ACL, IP prefix, and routing policy, to filter routes so that only IS-IS routes that meet the specified conditions can add to an IP routing table. IS-IS routes that do not meet the specified conditions cannot be added to the IP routing table and cannot be selected to forward IP packets.
isis [ process-id ]
filter-policy { acl-number | ip-prefix ip-prefix-name | route-policy route-policy-name } import