Patent ID: 8868788

Claim:
A method comprising: receiving, by a first server, an uncompressed session initiation protocol registration request including an indicator of a first version of a static dictionary, the uncompressed session initiation protocol registration request being sent by user equipment; transmitting to the user equipment a session initiation protocol response including an authentication challenge and an indication that the first version and a second version of the static dictionary are available; receiving, by the first server, a compressed session initiation protocol registration request in response to the authentication challenge, the compressed session initiation protocol registration request including authentication credentials and being compressed according to the first version of the static dictionary; and transmitting subsequent messages to the user equipment compressed using the first version of the dictionary; and transmitting, by the first server to the user equipment, a session initiation protocol message that informs the user equipment of an address of a second server configured to provide the second static dictionary to the user equipment, wherein the first server is included in a first network associated with a first service provider and the second server is included in a second network associated with a second service provider, the second service provider being different from the first service provider.