An SIP message processing method is disclosed. It may be performed by a node of a telecommunications network having a home gateway connected to an IMS network core via an access connection, at least a first SIP terminal and a second SIP terminal locally connected to said home gateway. It may include obtaining a bandwidth of the access connection, receiving a first SIP message concerning the first SIP session, determining the bandwidth in use by the first SIP session as a function of the first SIP message, receiving a second SIP message concerning the second SIP session, determining a bandwidth authorized for the second SIP session as a function of the second SIP message, of the bandwidth of the access connection, and of the bandwidth in use by the first SIP session, and sending a third SIP message to the first terminal, the second terminal, or the IMS network core.