Routing Loops

Solution: Defining a Maximum


Define a limit on the number of hops to prevent infinite loops Solution: Split Horizon
It is never useful to send information about a route back in the direction from which the original packet came

Solution: Route Poisoning


Routers set the distance of routes that have gone down to infinity

Solution: Poison Reverse


Poison reverse overrides split horizon

Solution: Holddown Timers



The router keeps an entry for the network possibly down state, allowing time for other routers to recompute for this topology change.

Solution: Triggered Updates



The router sends updates when a change in its routing table occurs