Users Guide

Command History
This guide is platform-specic. For command information about other platforms, see the relevant Dell
Networking OS Command Line Reference Guide.
Version Description
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 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
prex length match a table entry. For example, when congured 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 prex length,
the status of the tracked route is considered to be DOWN.
When you congure 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 dierent 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 congured 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 congure 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 notication of a
change in the state of a tracked object is sent when a metric value crosses a congured threshold.
Related Commands
• show track – display information about tracked objects, including conguration, current state, and clients
which track the object.
• threshold metric – congure the metric threshold used to determine the UP and/or DOWN state of a
tracked route.
• track resolution ip route – congure the protocol-specic resolution value used to scale an IPv4 route
metric.
track ip host reachability
Congure object tracking on the reachability of an IPv4 host.
Syntax
track object-id ip host host-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.
Object Tracking
1083