674 BigIron RX Series Configuration Guide53-1002253-01Configuring RIP parameters24To disable split horizon and enable poison reverse on an interface, enter the command such as thefollowing.BigIron RX(config-if-e10000-1/1)# ip rip poison-reverseYou can configure the device to avoid routing loops by advertising local RIP routes with a cost of 16(“infinite” or “unreachable”) when these routes go down.BigIron RX(config-rip-router)# poison-local-routesSyntax: [no] poison-local-routesSuppressing RIP route advertisement on a VRRP or VRRPEbackup interfaceNOTEThis section applies only if you configure the device for Virtual Router Redundancy Protocol (VRRP)or VRRP Extended (VRRPE). Refer to Chapter 17, “Configuring VRRP and VRRPE”.Normally, a VRRP or VRRPE Backup includes route information for the virtual IP address (thebacked up interface) in RIP advertisements. As a result, other routers receive multiple paths for thebacked up interface and might sometimes unsuccessfully use the path to the Backup rather thanthe path to the Master.You can prevent the Backups from advertising route information for the backed up interface byenabling suppression of the advertisements.To suppress RIP advertisements for the backed up interface in Router2, enter the followingcommands.Router2(config)# router ripRouter2(config-rip-router)# use-vrrp-pathSyntax: [no] use-vrrp-pathThe syntax is the same for VRRP and VRRPE.Using prefix lists and route maps as route filtersYou can configure prefix lists to permit or deny specific routes, then apply them globally or toindividual interfaces and specify whether the lists apply to learned routes (in) or advertised routes(out).You can configure route maps to permit or deny specific routes, then apply a route map to aninterface, and specify whether the map applies to learned routes (in) or advertised routes (out).NOTEA route is defined by the destination’s IP address and network mask.NOTEBy default, routes that do not match a prefix list are learned or advertised. To prevent a route frombeing learned or advertised, you must configure a prefix list to deny the route.To configure a prefix list, enter commands such as the following.
