Version Description
8.3.12.0 Introduced on the S4810.
8.4.1.0 Introduced.
Usage
Information Use this command to create an object that tracks the UP and/or DOWN threshold
of an IPv4 route metric. In order for a route’s metric 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 the threshold of an IPv4 route metric as a tracked object, the
UP/DOWN state of the tracked route is also determined by the current metric for
the route 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
scaled metric value communicated to a client always considers a lower value to
have priority over a higher value. The resulting scaled value is compared against the
configured threshold values to determine the state of a tracked route as follows:
• If the scaled metric for a route entry is less than or equal to the UP threshold,
the state of a route is UP.
• If the scaled metric for a route is greater than or equal to the DOWN threshold
or the route is not entered in the routing table, the state of a route is DOWN.
You configure the UP and DOWN thresholds for each tracked route by using the
threshold metric command. The default UP threshold is 254; the default
DOWN threshold is 255. The notification of a change in the state of a tracked
object is sent when a metric value crosses a configured threshold.
Related
Commands •show track �� displays information about tracked objects, including
configuration, current state, and clients which track the object.
•threshold metric – configures the metric threshold used to determine the UP
and/or DOWN state of a tracked route.
•track resolution ip route – configures the protocol-specific resolution value
used to scale an IPv4 route metric.
track ip route reachability
Configure object tracking on the reachability of an IPv4 route.
Syntax track object-id ip route ip-address/prefix-len reachability
[vrf vrf-name]
To return to the default setting, use the no track object-id command.
Object Tracking 1049