Patent ID: 7213263
Filing Date: 2007-05-01
Classification: H04L,H04W

Abstract:
1. A method of establishing and maintaining secure communications between a home network server that is associated with a home network and a client when the client roams from the home network to a new location outside of the home network, the method comprising: at the client, establishing a new Internet Protocol address associated with the new location, wherein the client has a permanent Internet Protocol address associated with the home network; at the client, transmitting a registration message, to a relay server that is coupled to the home network server, wherein the registration message identifies the new Internet Protocol address associated with the permanent Internet Protocol address; at the relay server, authenticating the registration message; at the relay server, encapsulating the registration message; at the relay server, transmitting the encapsulated registration message to the home network server; establishing a security association between the home network server and the relay server; at the home network server, registering the new Internet Protocol address as a care-of-address for the client; at the home network server, transmitting a reply message to the client confirming registration of the new Internet Protocol address as the care-of address for the client, thereby establishing a tunnel between the home network server and the client via the relay; establishing a security association between the home network server and the client inside the tunnel; at the home network server, performing network address translation between the permanent IP address and the new Internet Protocol address for packets addressed to the client; and at the home network server, encapsulating the packets that are addressed to the client based on the security association between the home network server and the client, wherein establishing the security association between the home network server and the relay server comprises: at the relay server, authenticating the home network server; at the home network server, authenticating the relay server; establishing a secure channel for negotiations between the relay server and the home network server; and using the secure channel, negotiating security parameters to establish the security association between the relay server and the home network server, wherein the security parameters comprise an encryption method, an integrity method, and a lifetime of the security association.