Method and apparatus for handling network resource failures in a router

Abstract

There is provided a method for use by a router in a communications network. Forwarding information is maintained (S) which specifies the next hop node for each of a plurality of possible destination nodes. Update information is maintained (S) which specifies how, if at all, the next hop nodes specified in the forwarding information are to be updated for a plurality of possible network resource failures. Known failure information is maintained (S) which relates to a known network resource failure or which specifies that there is no known network resource failure. A failure notification is received (S) relating to a network resource failure. In response to receipt of the failure notification, it is determined (S) from the failure notification how, if at all, the known failure information is to be updated, and the known failure information is updated, if required, based on the determination (S). A communications packet is received (S). Various steps (Sto S) are carried out in response to receipt of the communications packet. The destination node for the received packet is determined (S). It is determined (S) whether the next hop node specified by the forwarding information for the determined destination node is potentially invalid in view of the known failure information. If so, then the next hop node for the determined destination node is updated if necessary in the forwarding information using the update information and the known failure information (S). The next hop node is determined for the received packet using the forwarding information and the determined destination node (S). The received packet is forwarded towards the determined next hop node (S).