A telecommunications network, comprising: a call-control server (112, 236, 510); and an anchoring network device (400, 504) configured to: proxy signaling traffic for a communication session; determine (704, 508, 608) a routing identifier based at least in part on information of the one of a first access network of a first type and a second access network of a second, different type carrying the communication session; and transmit state information of the communication session in association with the routing identifier, to the call-control server; characterized in that: the call-control server is configured to be responsive to the state information of the communication session and to transmit control information of the communication session to the anchoring network device, the anchoring network device is further configured to perform, in response to receiving the control information, at least one of: transfer the communication session; update charging records of the communication session; update consumption counters of the communication session; update consumption limits of the communication session; add one or more participants to the communication session; or drop one or more participants to the communication session. a call-control server (112, 236, 510); and an anchoring network device (400, 504) configured to: proxy signaling traffic for a communication session; determine (704, 508, 608) a routing identifier based at least in part on information of the one of a first access network of a first type and a second access network of a second, different type carrying the communication session; and transmit state information of the communication session in association with the routing identifier, to the call-control server; characterized in that: the call-control server is configured to be responsive to the state information of the communication session and to transmit control information of the communication session to the anchoring network device, the anchoring network device is further configured to perform, in response to receiving the control information, at least one of: transfer the communication session; update charging records of the communication session; update consumption counters of the communication session; update consumption limits of the communication session; add one or more participants to the communication session; or drop one or more participants to the communication session. proxy signaling traffic for a communication session; determine (704, 508, 608) a routing identifier based at least in part on information of the one of a first access network of a first type and a second access network of a second, different type carrying the communication session; and transmit state information of the communication session in association with the routing identifier, to the call-control server; characterized in that: the call-control server is configured to be responsive to the state information of the communication session and to transmit control information of the communication session to the anchoring network device, the anchoring network device is further configured to perform, in response to receiving the control information, at least one of: transfer the communication session; update charging records of the communication session; update consumption counters of the communication session; update consumption limits of the communication session; add one or more participants to the communication session; or drop one or more participants to the communication session. the call-control server is configured to be responsive to the state information of the communication session and to transmit control information of the communication session to the anchoring network device, the anchoring network device is further configured to perform, in response to receiving the control information, at least one of: transfer the communication session; update charging records of the communication session; update consumption counters of the communication session; update consumption limits of the communication session; add one or more participants to the communication session; or drop one or more participants to the communication session. transfer the communication session; update charging records of the communication session; update consumption counters of the communication session; update consumption limits of the communication session; add one or more participants to the communication session; or drop one or more participants to the communication session.