Network entity and method for managing Session Initiation Protocol communications towards a user entity in a communication network

A system for managing Session Initiation Protocol communications in an IP Multimedia Subsystem communication network, the system comprising:

• a network entity for managing the Session Initiation Protocol communications towards a user entity in the communication network, the network entity including:
• a receiver for receiving a first Session Initiation Protocol message from a second network entity comprising a Serving Call Session Control Function (S-CSCF);
• a transmitter for transmitting a second Session Initiation Protocol message over the communication network towards a third network entity comprising an application server;
• and
• a processor for generating the second Session Initiation Protocol message in response to receiving the first Session Initiation Protocol message, the second Session Initiation Protocol message having user-specific data relating to the user entity, wherein the user-specific data is received from a fourth network entity comprising a Home Subscriber Server (HSS),
• wherein the processor is configured to insert the user-specific data into the first Session Initiation Protocol message for generating the second Session Initiation Protocol message, and the user-specific data indicates a current communication status of the user entity in both a packet-switched domain and a circuit-switched domain of the communication network;
• the second network entity being a hardware entity comprising the Serving Call Session Control Function;
• the third network entity comprising the application server;
• and
• a fifth network entity comprising a Proxy Call Session Control Function (P-CSCF), wherein
• the network entity is configured to transmit the second Session Initiation Protocol message including the user-specific data towards the second network entity;
• wherein
• the second network entity is configured to forward the second Session Initiation Protocol message towards the application server comprised in the third network entity, the application server using the user-specific data;
• and wherein
• the second network entity is configured to remove the user-specific data from the second Session Initiation Protocol message before forwarding the second Session Initiation Protocol message towards the P-CSCF comprised in the fifth network entity.