Examples of Configuring Object Tracking for an IPv4 or IPv6 InterfaceExamples of Configuring Object Tracking for an IPv4 or IPv6 InterfaceThe following is an example of configuring object tracking for an IPv4 interface:Dell(conf)#track 101 interface tengigabitethernet 7/2/1 ip routingDell(conf-track-101)#delay up 20Dell(conf-track-101)#description NYC metroDell(conf-track-101)#endDell#show track 101Track 101Interface TenGigabitEthernet 7/2/1 ip routingDescription: NYC metroThe following is an example of configuring object tracking for an IPv6 interface:Dell(conf)#track 103 interface tengigabitethernet 7/11/1 ipv6routingDell(conf-track-103)#description Austin access pointDell(conf-track-103)#endDell#show track 103Track 103Interface TenGigabitEthernet 7/11/1 ipv6 routingDescription: Austin access pointTrack an IPv4/IPv6 RouteYou can create an object that tracks the reachability or metric of an IPv4 or IPv6 route.You specify the route to be tracked by its address and prefix-length values. Optionally, for an IPv4 route,you can enter a VRF instance name if the route is part of a VPN routing and forwarding (VRF) table. Thenext-hop address is not part of the definition of a tracked IPv4/IPv6 route.In order for an route’s reachability or metric to be tracked, the route must appear as an entry in therouting table. A tracked route is considered to match an entry in the routing table only if the exact IPv4 orIPv6 address and prefix length match an entry in the table. For example, when configured as a trackedroute, 10.0.0.0/24 does not match the routing table entry 10.0.0.0/8. Similarly, for an IPv6 address,3333:100:200:300:400::/80 does not match routing table entry 3333:100:200:300::/64. If no route-tableentry has the exact IPv4/IPv6 address and prefix length, the tracked route is considered to be DOWN.In addition to the entry of a route in the routing table, you can configure the UP/DOWN state of a trackedroute to be determined in the following ways:• By the reachability of the route's next-hop router.The UP/DOWN state of the route is determined by the entry of the next-hop address in the ARPcache. A tracked route is considered to be reachable if there is an ARP cache entry for the route'snext-hop address. If the next-hop address in the ARP cache ages out for a route tracked for itsreachability, an attempt is made to regenerate the ARP cache entry to see if the next-hop addressappears before considering the route DOWN.• By comparing the threshold for a route’s metric with current entries in the route table.The UP/DOWN state of the tracked route is determined by the threshold for the current value of theroute metric in the routing table.To provide a common tracking interface for different clients, route metrics are scaled in the rangefrom 0 to 255, where 0 is connected and 255 is inaccessible. The scaled metric value communicated608 Object Tracking
