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vrf vrf-name (Optional) E-Series only: You can configure a VPN routing and forwarding (VRF)
instance to specify the virtual routing table to which the tracked route belongs.
Defaults none
Command Modes CONFIGURATION
Command
History
Version Description
9.7(0.0) Introduced on the M I/O Aggregator.
Usage
Information
Use this command to create an object that tracks the reachability of an IPv4 route. In order for a route’s
reachability to be tracked, the route must appear as an entry in the routing table.
A tracked IPv4 route is considered to match an entry in the routing table only if the exact IPv4 address
and prefix length match a table entry. For example, when configured as a tracked route, 10.0.0.0/24 does
not match the routing table entry 10.0.0.0/8. If no route-table entry has the exact IPv4 address and
prefix length, the status of the tracked route is considered to be DOWN.
When you configure IPv4 route reachability as a tracked object, the UP/DOWN state of the tracked route
is also determined by the entry of the next-hop address in the ARP cache. A tracked route is considered
to be reachable if there is an ARP cache entry for the route's next-hop address.
If the next-hop address in the ARP cache ages out for a route tracked for its reachability, an attempt is
made to regenerate the ARP cache entry to if the next-hop address appears before considering the route
DOWN.
Related
Commands
● show track – displays information about tracked objects, including configuration, current state, and
clients which track the object.
● track ip route metric threshold – configures object tracking on the threshold of an IPv4 route metric.
track resolution ip route
Configure the protocol-specific resolution value used to scale an IPv4 route metric.
Syntax
track resolution ip route {isis resolution-value | ospf resolution-value}
To return to the default setting, use the no track object-id command.
Parameters
object-id Enter the ID number of the tracked object. The range is 1 to 500.
isis resolution-
value
Enter the resolution used to convert the metric in the routing table for ISIS routes
to a scaled metric.
ospf resolution-
value
Enter the resolution used to convert the metric in the routing table for OSPF
routes to a scaled metric.
Defaults none
Command Modes CONFIGURATION
Command
History
Version Description
9.7(0.0) Introduced on the M I/O Aggregator.
Usage
Information
Use this command to configure the protocol-specific resolution value that converts the actual metric of
an IPv4 route in the routing table to a scaled metric in the range 0 to 255.
The UP/DOWN state of a tracked IPv4 route is determined by a user-configurable threshold (the
threshold metric command) for the route’s metric in the routing table. To provide a common
tracking interface for different clients, route metrics are scaled in the range 0 to 255, where 0 is
connected and 255 is inaccessible.
The protocol-specific resolution value calculates the scaled metric by dividing a route's cost by the
resolution value set for the route protocol:
● For ISIS, you can set the resolution in the range 1 to 1000, where the default is 10.
266 Object Tracking