IMS PERFORMANCE MONITORING

A method and apparatus enabling performance monitoring in packet-switched IP networks such as those configured according to an IP multimedia subsystem, IMS, architecture. Performance is monitored by reconstructing selected control signaling sequences. The control signaling sequences, which are typically executed according a signaling protocol such as the Session Initiation Protocol, SIP, are reconstructed by parsing the contents of monitoring request headers configured, modified, and attached to control messages according to the present invention. The header includes at least an IMS monitoring ID field (510) for identifying the signaling sequence to be reconstructed, a processing node ID field (520) for representing the entities processing the messages, and a requester ID field (530) for identifying a requesting entity. It may also specify a monitoring level (540) indicative of the monitoring tasks required. The monitoring may be requested by an IMS node, or by an entity outside the IMS.