Specifications

IP Switching Commands
ip cache-invalidate-delay
ISW-33
Cisco IOS IP Switching Command Reference
May 2008
This command controls how the route cache is flushed. The intent is to delay invalidation of the cache
until after routing has settled down. Because route table changes tend to be clustered in a short period
of time, and the cache may be flushed repeatedly, a high CPU load might be placed on the router.
When this feature is enabled, and the system requests that the route cache be flushed, the request is held
for at least minimum seconds. Then the system determines whether the cache has been “quiet” (that is,
less than threshold invalidation requests in the last quiet seconds). If the cache has been quiet, the cache
is then flushed. If the cache does not become quiet within maximum seconds after the first request, it is
flushed unconditionally.
Manipulation of these parameters trades off CPU utilization versus route convergence time. Timing of
the routing protocols is not affected, but removal of stale cache entries is affected.
Examples The following example shows how to set a minimum delay of 5 seconds, a maximum delay of 30
seconds, and a quiet threshold of no more than 5 invalidation requests in the previous 10 seconds:
Router(config)# service internal
Router(config)# ip cache-invalidate-delay 5 30 10 5
Related Commands Command Description
ip route-cache Configures the high-speed switching caches for IP routing.