A method and a system for speeding up session establishment are provided, wherein the time required to establish a session is reduced, even in the case where a session management server requires a large amount of time to process respective functions required for establishing the session (such as making a decision regarding whether to permit or deny provision of a service, or generating a session key).The session management server is provided with means for conducting, in parallel, processing to issue processing requests for respective functions required for establishing a session (such as making a decision regarding whether to permit or deny provision of a service, or generating a session key) and processing to forward a communication message transmitted by a communications device or another session management server attempting to establish a session.