Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 135

CONFIG-ROUTE-MAP mode set tag tag-value • Specify a value as the route's weight. CONFIG-ROUTE-MAP mode set weight value To create route map instances, use these commands. There is no limit to the number of set commands per route map, but the convention is to keep the number of set filters in a route map low. Set commands do not require a corresponding match command. Configure a Route Map for Route Redistribution Route maps on their own cannot affect traffic and must be included in different commands to affect routing traffic. Route redistribution occurs when the system learns the advertising routes from static or directly connected routes or another routing protocol. Different protocols assign different values to redistributed routes to identify either the routes and their origins. The metric value is the most common attribute that is changed to properly redistribute other routes into a routing protocol. Other attributes that can be changed include the metric type (for example, external and internal route types in OSPF) and route tag. Use the redistribute command in OSPF, RIP, ISIS, and BGP to set some of these attributes for routes that are redistributed into those protocols. Route maps add to that redistribution capability by allowing you to match specific routes and set or change more attributes when redistributing those routes. In the following example, the redistribute command calls the route map static ospf to redistribute only certain static routes into OSPF. According to the route map static ospf, only routes that have a next hop of Tengigabitethernet interface 0/0 and that have a metric of 255 are redistributed into the OSPF backbone area. NOTE: When re-distributing routes using route-maps, you must create the route-map defined in the redistribute command under the routing protocol. If you do not create a route-map, NO routes are redistributed. Example of Calling a Route Map to Redistribute Specified Routes router ospf 34 default-information originate metric-type 1 redistribute static metric 20 metric-type 2 tag 0 route-map staticospf ! route-map staticospf permit 10 match interface TengigabitEthernet 0/0 match metric 255 set level backbone Configure a Route Map for Route Tagging One method for identifying routes from different routing protocols is to assign a tag to routes from that protocol. As the route enters a different routing domain, it is tagged. The tag is passed along with the route as it passes through different routing protocols. You can use this tag when the route leaves a routing domain to redistribute those routes again. In the following example, the redistribute ospf command with a route map is used in ROUTER RIP mode to apply a tag of 34 to all internal OSPF routes that are redistributed into RIP. Example of the redistribute Command Using a Route Tag ! router rip redistribute ospf 34 metric 1 route-map torip ! route-map torip permit 10 match route-type internal Access Control Lists (ACLs) 135