Abstract: A method of access control of a multimedia session between a terminal A and a terminal B connected to a telecommunication network wherein, prior to session set-up, the terminal A transmits to the terminal B a message containing a list of codecs to be used to encode the information to be exchanged during the session to be set up, and at the end of a session, the terminal A transmits to the terminal B a request to close the session. The method intercepts the message containing the list of codecs, modifies the list of codecs proposed by the intercepted message to take into account actual bandwidth resources available for the link between the terminals, transmits to the terminal B the message containing the modified list of codecs, and reserves the resources and updates the database for using access resources.