Service Manual

A tracked IPv6 route is considered to match an entry in the routing table only if the
exact IPv6 address and prefix length match a table entry. For example, when configured
as a tracked route, 3333:100:200:300:400::/80 does not match routing table entry
3333:100:200:300::/64. If no route-table entry has the exact IPv6 address and prefix
length, the status of the tracked route is considered to be DOWN.
When you configure the threshold of an IPv6 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 IPv6 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 ipv6 route – display information about tracked IPv6 routes, including
configuration, current state, and clients which track the route.
• threshold metric – configure the metric threshold used to determine the UP
and/or DOWN state of a tracked route.
• track resolution ipv6 route – configure the protocol-specific resolution value
used to scale an IPv6 route metric.
track ipv6 route reachability
Configure object tracking on the reachability of an IPv6 route.
Syntax
track object-id ipv6 route ip-address/prefix-len reachability
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.
ipv6-address/
prefix-len
Enter an IPv6 address in X:X:X:X::X format. The valid IPv6 prefix
lengths are from /0 to / 128.
Defaults None
Command Modes CONFIGURATION
Object Tracking 1339