Patent ID: 8705439
Filing Date: 2014-04-22
Classification: H04L,H04W

Abstract:
1. A method of handling mobility-related signaling in a communications system comprising a mobile node, a mobile router, and a peer node, the method comprising: providing the mobile router with a delegation certificate that is cryptographically signed by or on behalf of the mobile node; maintaining a counter at the mobile router and incrementing the counter for each mobility-related signaling exchange conducted by the mobile router with the peer node on behalf of the mobile node; at the mobile router for each mobility-related signaling exchange initiated with the peer node on behalf of the mobile node, providing to the peer node within this exchange, said delegation certificate or an identification of the certificate and a sequence number associated with the certificate as defined by the current value of said counter; at the peer node, maintaining a counter synchronized with said counter maintained at the mobile router and, for each mobility-related signaling exchange conducted with the mobile router, comparing the received sequence number with a sequence number as defined by the current value of the counter maintained by the peer node in respect of the delegation certificate, and authorizing the mobility-related signaling exchange in dependence upon the result of the comparison; and wherein the mobile router maintains the counter which is dedicated to keeping track of a number of mobility-related signaling exchanges conducted by the mobile router with the peer node on behalf of the mobile node; wherein the peer node maintains the counter which is dedicated to keeping track of a number of mobility-related signaling exchanges conducted by the mobile router with the peer node on behalf of the mobile node; at the peer node, maintaining a second counter synchronized with a counter maintained at the mobile node and, for each mobility-related signaling exchange initiated directly by the mobile node with the peer node, comparing a received sequence number with a sequence number as defined by a current value of the second counter maintained by the peer node with respect to a second delegation certificate associated with the mobile node, and authorizing the mobility-related signaling exchange in dependence upon the result of the comparison; and wherein the peer node maintains the second counter dedicated to keeping track of a number of mobility-related signaling exchanges initiated directly by the mobile node with the peer node.