te maps can also alter packets, while access lists cannot. The set route map com- mand allows you to change all sorts of things in a packet as it's being sent. You can change the interface to which the packet is being sent, the next hop of the packet, and quality of service (QoS) values such as IP precedence: R1 (config-route-map)# ? as-path Prepend string for a BGP AS-path attribute automatic-tag Automatically compute TAG value OSI summary address comm-list Set BGP community list (for deletion) community BGP community attribute dampening Set BGP route flap dampening parameters default Set default information extcommunity BGP extended community attribute interface Output interface IP specific information level Where to import route local-preference BGP local preference path attribute metric Metric value for destination routing protocol metric-type Type of metric for destination routing protocol origin BGP origin code Tag value for destination routing protocol weight BGP weight for routing table The IP-specific items that can be changed are accessed under the ip category: R1(config-route-map)#set ip ? default Set default information Set DF bit next-hop Next hop address precedence Set precedence field qos-group Set QOS Group ID Set type of service field Policy routing is the term for using a route map to change information regarding where a packet is routed. Use care when policy routing, as policy-routing scenarios can involve process switching (which can put a serious strain on the router's CPU). Process switch- ing is discussed in Chapter 15. Building a Route Map Route maps are named and built from clauses. The name is included in each clause, and the clauses are numbered to specify the order in which they should be evaluated and to allow you to include or omit only certain steps without having to reenter the Chapter 14: Route Maps entire route map. The default clause number is 10, and it's good practice to number your clauses in intervals of 10. This allows you to insert multiple clauses without need- ing to red