Users Guide

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 – 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 ip route – configure 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.
Parameters
object-id Enter the ID number of the tracked object. The range is 1 to 500.
ip-address/
prefix-len
Enter an IPv4 address in dotted decimal format. The valid IPv4 prefix lengths are from /0
to /32.
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
This guide is platform-specific. For command information about other platforms, see the relevant Dell Networking
OS Command Line Reference Guide.
Version Description
9.8(2.0) Introduced on the S3100 series.
9.8(1.0) Introduced on the Z9100-ON.
9.8(0.0P5) Introduced on the S4048-ON.
9.8(0.0P2) Introduced on the S3048-ON.
9.7(0.0) Introduced on the S6000-ON.
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 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.
894 Object Tracking