Change the route-ttl time to control how long routes remain in a cluster unit routing table. The time to live range is 0 to 3600 seconds. The default time to live is 10 seconds.

The time to live controls how long routes remain active in a cluster unit routing table after the cluster unit becomes a primary unit. To maintain communication sessions after a cluster unit becomes a primary unit, routes remain active in the routing table for the route time to live while the new primary unit acquires new routes.

If route-ttl is set to 0 the primary unit must acquire all new routes before it can continue processing traffic. By default, route-ttl is set to 10 which may mean that only a few routes will remain in the routing table after a failover. Normally keeping route-ttl to 10 or reducing the value to 0 is acceptable because acquiring new routes usually occurs very quickly, especially if graceful restart is enabled, so only a minor delay is caused by acquiring new routes.

If the primary unit needs to acquire a very large number of routes, or if for other reasons, there is a delay in acquiring all routes, the primary unit may not be able to maintain all communication sessions.

You can increase the route time to live if you find that communication sessions are lost after a failover so that the primary unit can use synchronized routes that are already in the routing table, instead of waiting to acquire new routes.