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Defaults
Command Modes
Command
History
Related
Commands
Usage
Information
track ip route reachability
c e s
Syntax
994
|
Object Tracking
ip-address/
Enter an IPv4 address in dotted decimal format. Valid IPv4 prefix lengths are from /0 to
/32.
prefix-len
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.
None
CONFIGURATION
Version 8.4.1.0
Introduced
show track
Display information about tracked objects, including configuration, current state, and
clients which track the object.
threshold metric
Configure the metric threshold used to determine the UP and/or DOWN state of a tracked
route.
track resolution
Configure the protocol-specific resolution value used to scale an IPv4 route metric.
ip route
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
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.
Configure object tracking on the reachability of an IPv4 route.
track object-id ip route ip-address/prefix-len reachability [vrf vrf-name]
To return to the default setting, enter no track object-id.
threshold metric
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