1. A method for policy based routing, comprising: determining, by a device for policy based routing, each interface in a first redirection group is unreachable to a destination of traffic and multiple interfaces in a second redirection group are reachable to the destination, where each interface in the first redirection group has a first same next hop to the destination and each interface in the second redirection group has a second same next hop to the destination; switching, by the device, the traffic from the first redirection group to the second redirection group for transmitting the traffic on the multiple interfaces in the second redirection group reachable to the destination.