Granted Patent B2

US 8,094,565 · App. 12/529,299 · Granted Jan 10, 2012

Abstract

Claims (29)

1. A method for loop detection in data packet communication utilizing a tunnel in a network comprising a plurality of nodes, the method comprising the steps of:

when a first node transmits a data packet:

encoding an identification of the first node in at least two header fields of the data packet to be transmitted, and

when the first node receives a data packet:

analyzing at least two header fields of the received data packet, and

deciding if a loop exists by determining if the received data packet is the transmitted data packet sent by the first node itself, based on the analysis of the at least two header fields of the received data packet,

wherein the at least two header fields of the transmitted data packet and the received data packet are tunnel encapsulation limit fields of an extended IPv6 header, and the method further comprises the step of:

reducing a value of bytes in the tunnel encapsulation limit fields by 1 in each node in the network that further encapsulates the transmitted data packet.

2. The method according to claim 1 , wherein the first node is a home agent or a router.

3. The method according to claim 1 , wherein the step of analyzing comprises:

comparing the at least two header fields of the received data packet with the encoded identification of the first node,

if the at least two header fields of the received data packet originate at the first node, deciding that the loop exists,

otherwise, deciding that the loop does not exist.

4. The method according to claim 3 , wherein the step of comparing comprises:

subtracting individual bytes of the tunnel encapsulation limit fields in the received data packet from respective individual bytes of the encoded identification of the first node, and

deciding that the loop exists if each of the resulting bytes from the subtracting are the same.

5. The method according to claim 1 , wherein the transmitted data packet is a binding refresh advice packet.

6. The method according to claim 5 , wherein the step of deciding that the loop exists further comprises:

determining whether a binding update has been received within a given time from transmission of the binding refresh advice packet, and

deciding that the loop does not exist if the binding update has been received within the given time.

7. A non-transitory computer readable medium storing instructions that, when executed by a processor of a node, cause the node to detect a loop in data packet communication utilizing a tunnel in a network comprising a plurality of nodes, by performing a method comprising the steps of:

when a first node transmits a data packet:

encoding an identification of the first node in at least two header fields of the data packet to be transmitted, and

when the first node receives a data packet:

analyzing at least two header fields of the received data packet, and

deciding if a loop exists by determining if the received data packet is the transmitted data packet sent by the first node itself, based on the analysis of the at least two header fields of the received data packet,

wherein the at least two header fields of the transmitted data packet and the received data packet are tunnel encapsulation limit fields of an extended Ipv6 header, and the method further comprises the step of:

reducing a value of bytes in the tunnel encapsulation limit field by 1 in each node in the network that further encapsulates the transmitted data packet.

8. The non-transitory computer readable medium according to claim 7 , wherein the first node is a home agent or a router.

Assignments (13)