Patent ID: 8700692

Claim:
A method of operating a node of an IP Multimedia Subsystem (IMS), said IMS comprising nodes for performing predefined IMS functions, Application Servers (AS) for providing services to devices that access said IMS, and a Home Subscription Server (HSS) for holding user profiles for said devices, said method implemented by said node comprising the steps of: receiving, in said node, a user profile related to a registration in the IMS of one of said devices, where the user profile contains initial filter criteria (IFC) operative to trigger a provision of services for said device; determining, in said node, whether said user profile for said device contains functioning instructions operative to change the predefined IMS functions of the one or more IMS nodes and, if so, retrieving said functioning instructions from said user profile, wherein said functioning instructions comprise a formatting rule instruction that defines for a field of a message from a source node to a destination node in the IMS a location of a substitute content for that field; storing, in said node, said functioning instructions together with a registered Public User Identity for said device; and, in response to receiving a request containing said Public User Identity for an IMS service, executing, in said node, said functioning instructions instead of said predefined IMS functions.