Service Manual

• 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 IPv6 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 ipv6 route – displays information about tracked IPv6 routes, including conguration, current
state, and clients which track the route.
• threshold metric – congures the metric threshold used to determine the UP and/or DOWN state of a
tracked route.
• track resolution ipv6 route – congures the protocol-specic resolution value used to scale an IPv6 route
metric.
track ipv6 route reachability
Congure 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/
prex-len
Enter an IPv6 address in X:X:X:X::X format. The valid IPv6 prex lengths are
from /0 to / 128.
Defaults none
Command Modes CONFIGURATION
Command History
Version Description
9.8(0.0) Introduced on the S3048-ON and S4048-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 IPv6 route. In order for a route’s
reachability to be tracked, the route must appear as an entry in the routing table.
A tracked route is considered to match an entry in the routing table only if the exact IPv6 address and prex
length match a table entry. For example, when congured 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 prex length, the tracked route is considered to be DOWN.
When you congure IPv6 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.
If the next-hop address in the ARP cache ages out for a route tracked for its reachability, an attempt is
made to regenerate the ARP cache entry to if the next-hop address appears before considering the route
DOWN.
982
Object Tracking