Exporting routes from one protocol to another and in the reverse direction are discrete configuration functions. For example, to run IS-IS and RIP simultaneously, you must first configure both protocols and then verify the independent operation of each. Then you can configure the routes to export from IS-IS to RIP and the routes to export from RIP to IS-IS. Likewise, for any other combinations of protocols, you must separately configure each to export routes to the other.
This section describes how to inject routing information learned from other IP routing protocols into an IS-IS domain, thereby advertising their reachability in the IS-IS domain. These routes are included in the locally originated LSPs. For information on exporting routes learned in IS-IS to another routing protocol, see the chapter that describes the destination routing protocol.
When you export routes from another protocol to IS-IS, the metric and the type of metric are configured. You can also configure a policy to filter out unwanted external routes.