Technique for handling forwarding transients with link state routing protocol

Claim 3

The method of claim 1 further comprising the step of invoking one of a plurality of forwarding options with respect to a packet received at the router and intended for the destination station to suppress forwarding loops during the routing transients.

Claim 4

The method of claim 2 wherein the step of invoking one of the forwarding options comprises the step of discarding the packet.

Claim 5

The method of claim 2 wherein the step of invoking one of the forwarding options comprises the steps of: decrementing one of a time-to-live and lifetime entry of a network layer header of the packet; and forwarding the packet to the destination station over the computed path.

Claim 6

The method of claim 1 further comprising the steps of: constructing augmented forwarding databases at the router and the NH neighbor; and storing the first hop-count (D) in the router's augmented forwarding database and the second hop-count (D) in the NH neighbor's augmented forwarding database.

Claim 7

Apparatus for detecting inconsistencies in views of paths to a destination station of a computer network, the apparatus comprising: a router coupled to the network, the router having a processing element for processing routing information to compute a path and first hop-count parameter from the router to the destination station; a neighboring router coupled to the router via the network, the neighboring router having a processing element for processing routing information to compute a path and second hop-count parameter from the neighboring router to the destination; means, coupled to the router, for executing a control mechanism to determine whether the second hop-count parameter is less than the first hop-count parameter; and means, coupled to the router, for invoking a forwarding mechanism with respect to a packet intended for the destination station if the second hop-count parameter is not less than the first hop-count parameter.

Claim 8

Apparatus for detecting inconsistencies in views of paths to a destination station of a computer network, the apparatus comprising: a router coupled to the network, the router having a processing element for processing routing information to compute a path and first hop-count parameter from the router to the destination station; a neighboring router coupled to the router via the network, the neighboring router having a processing element for processing routing information to compute a path and second hop-count parameter from the neighboring router to the destination; means, coupled to the router, for executing a control mechanism to determine whether the second hop-count parameter is less than the first hop-count parameter; and means, coupled to the router, for invoking a forwarding mechanism with respect to a packet intended for the destination station if the second hop-count parameter is not less than the first hop-count parameter.

Claim 9

The apparatus of claim 6 wherein the means for executing the control mechanism further comprises means for comparing the first hop-count parameter with the second hop-count parameter.

Claim 10

The apparatus of claim 7 further comprising an augmented forwarding database coupled to the router for storing the first hop-count parameter.

Claim 11

The apparatus of claim 8 wherein the means for invoking the forwarding mechanism comprises means for discarding the packet.

Claim 12

The apparatus of claim 8 wherein the means for invoking the forwarding mechanism comprises: means for decrementing one of a time-to-live and lifetime entry of a network layer header of the packet; and means for forwarding the packet to the destination station over the computed path.

Claim 13

A computer readable medium containing executable program instructions for efficiently detecting inconsistencies in forwarding databases of a router and its neighbor during routing transients in a computer network, the executable program instructions comprising program instructions for: computing a path and a first hop-count parameter to a destination station (hop-count (D)) at the router and a second hop-count (D) at the neighbor; transmitting an update message from the neighbor to the router when the second hop-count (D) changes, the update message containing an address of the destination station and the second hop-count (D) associated with that address; comparing the second hop-count (D) with the first hop-count (D); and detecting inconsistencies in the forwarding databases of the router and neighbor if the second hop-count (D) is not less than the first hop-count (D).

Claim 14

A computer readable medium containing executable program instructions for efficiently detecting inconsistencies in forwarding databases of a router and its neighbor during routing transients in a computer network, the executable program instructions comprising program instructions for: computing a path and a first hop-count parameter to a destination station (hop-count (D)) at the router and a second hop-count (D) at the neighbor; transmitting an update message from the neighbor to the router when the second hop-count (D) changes, the update message containing an address of the destination station and the second hop-count (D) associated with that address; comparing the second hop-count (D) with the first hop-count (D); and detecting inconsistencies in the forwarding databases of the router and neighbor if the second hop-count (D) is not less than the first hop-count (D).

Claim 15

The medium of claim 11 further comprising program instructions for invoking one of a plurality of forwarding options with respect to a packet received at the router and intended for the destination station to suppress forwarding loops during the routing transients.

Claim 16

The medium of claim 12 wherein the program instructions for invoking one of the forwarding options comprises program instructions for discarding the packet.

Claim 17

The medium of claim 12 wherein the program instructions for invoking one of the forwarding options comprises program instructions for: decrementing one of a time-to-live and lifetime entry of a network layer header of the packet; and forwarding the packet to the destination station over the computed path.

Claim 18

The medium of claim 11 further comprising program instructions for: constructing augmented forwarding databases at the router and the neighbor; and storing the first hop-count (D) in the router's augmented forwarding database and the second hop-count (D) in the neighbor's augmented forwarding database.