Method and system for providing updates on access network capability in an IP multimedia system network

A system for providing an update on access network capability to an IP Multimedia System (IMS) network, the system comprising:

• a User Equipment (UE) connected to the access network having
• a UE, client utilizing logic for sending a Session Initiation Protocol (SIP) registration request to the IMS network via
• a UE terminal, wherein the SIP registration request includes a P-Access-Network-Info header having a tag inserted by the UE client providing current information, including current roundtrip time in the access network, regarding a capability of the access network;
• a Proxy-CSCF for receiving the SIP registration request and
• an Application Server (AS), responsive to a triggering event said triggering event comprising one or more values including, a predetermined threshold value for the degree of change in measured average bandwidth within the access network or between the access and IMS networks for modulating service provisions according to the information regarding the capability of the access network available in the tag.