Providing a path of sufficient quality through a packet date network to support IMS services to a mobile node

摘要

A communication system comprises a packet data network 1 arranged to communicate data packets supporting a communication service to and from a communication terminal 13 via data path 18. A path computational element (PCE) 10 controls the data path 18, an application server 12 controls the comumunication service and an Internet Multimedia Subsystem (IMS) 14 controls the application server 12. The application server 12 provides the communication service to the communication terminal 13 in response to a registration request transmitted from the communication terminal 13 to the IMS 14 requesting an establishment of the communication service. When establishing the communication service, the IMS 14 communicates 19 an adaptation message to the PCE 10 including information indicating service quality parameters associated with the communication service. The PCE 10 calculates the data path 18 in accordance with the service quality parameters and adapts the packet data network 1 in accordance with the calculated data path 18.