Object tracking allows you to track specific objects on a device, such as the interface line protocol state, IP routing, and route reachability, and to take action when the tracked object's state changes. Tracking allows software clients to register interest in the behavior of an object, and receive notifications of changes. This object represents the state of the system functionality such as the status of an interface (up or down), the existence of an IP prefix in the Routing Information Base (RIB) and so on.

An IPv6 static route creates a tracked object-context for each tracked object. Tracked object contexts are stored in an AVL list that is maintained by the IPv6 static route and indexed by the object number. A tracked-object context is removed from the AVL list when the object is no longer associated with any IPv6 static routes. All IPv6 static routes associated with a tracked object is linked to the tracked object context by an indirect list. An IPv6 static route becomes a client of the tracked objects, and this allows the IPv6 static route to track the state of a tracked object. The ipv6 route command allows an IPv6 static route to be associated with a tracked object.

An IPv6 static route associated with a tracked-object is inserted into the IPv6 routing table if the state of the tracked-object is up and all other routing-table-insertion criteria are met.

The IPv6 Static Route Object Tracking feature uses the IPv6 static deferred state check mechanism to insert or delete a static route into or from the Routing Information Base (RIB). A change in the state of the tracked object is signaled from tracked objects and this causes IPv6 static to insert all IPv6 static routes associated with the tracked object into the state check queue (unless they are already in it). A separate process removes IPv6 static routes from the state check queue and determines whether these routes should be inserted into the RIB or removed from the RIB using the RIB insertion criteria.

The following insertion criteria must be met for an IPv6 static route to be inserted into the IPv6 routing table:

1. Interface is up.
2. Next-hop address is not the device's own address.
3. Next-hop address .
4. Next-hop address is resolved.
5. Bidirectional Forwarding Detection (BFD) session is up, if BFD tracking is configured.

   Note	An IPv6 static route can be associated with a tracked object and a BFD session. Both tracked object and BFD session state must be up before the IPv6 static route is inserted in the routing table.

6. Tracked object state is up.

An IPv6 static route in the routing table is removed if any of the insertion criteria becomes false.

1.    enable


2.    configure terminal


3.    ipv6 route vrf table-name-id ipv6-prefix {interface-type interface-number [next-hop-ipv6-address] | next-hop-ipv6-address} [admin-distance [multicast-vrf-distance]] [multicast] [nexthop-vrf table-name-id ] [unicast] [tag tag-value ] [track object-number ] namestatic-route ]}


4.    end


5.    show track object-number


6.    show ipv6 static vrf id

Device> enable

Device# configure terminal

Device(config)# ipv6 route vrf 3 2001:DB8:1:2::/64 GigabitEthernet0/0 2001:DB8:3:4::1 track 42

Device(config)# end

Device# show track 42

Device(config)# show ipv6 static vrf 3

Device# show track 42

Track 42
  IP route 10.21.12.0 255.255.255.0 reachability
  Reachability is Down (no ip route), delayed Up (1 sec remaining) (connected)
    1 change, last change 00:00:24
  Delay up 20 secs, down 10 secs
  First-hop interface is unknown (was GigabitEthernet1/0)
  Tracked by:
    HSRP GigabitEthernet0/0 3