Layer 3 Routing Commands 1528ipv6 nd nud retryThis command configures the exponential backoff multiple to be used in thecalculation of the next timeout value for Neighbor Solicitation transmissionduring NUD (neighbor unreachability detection) following the exponentialbackoff algorithm. Use the no form of the command to return the backoffmultiple to the default.Syntaxipv6 nd nud retry backoff-multipleno ipv6 nd nud retry• backoff-multiple—The value ranges from 1 to 5. The next timeout value isclamped at a maximum value of 60 seconds if the result of the exponentialback-off calculation is greater than 60 seconds.Default ConfigurationThe default exponent is 1.Command ModeGlobal ConfigurationUser GuidelinesOnce the neighbor is resolved and added in the hardware, traffic iscontinuously forwarded by the router using neighbor entry. The neighborentry in the cache transitions to the STALE state after the effective STALEtimeout value (a random value between 15 and 45 seconds per RFC 2461).To bridge the gap between the neighbor discovery state and the neighborcache state, the application periodically iterates through the STALE entriesand triggers NUD on those entries to detect any address/station movementsor MAC address changes.When NUD is triggered, neighbor solicitation PROBE packets (unicast andmulticast) are sent periodically, separated by exponential binary valuesinstead of the normal 1 second interval. This ensures that when the network(not just our router but more routers in the network) is congested, the NUDprocess for the existing STALE entries takes enough time before ultimatelyremoving the cache entry through garbage collection. Without the
