Setting Up A Call From A Non-IMS To An IMS Network Whereby The Gateway Interfaces The HSS

A Network Gateway Node, NGN, (500) for operating in a non-Internet Protocol Multimedia Subsystem, non-IMS, telecommunication network for setting up a call towards a destination node in an IMS network, the destination node serving a called terminal, the NGN comprising

• a Gateway Mobile Switching Centre, GMSC, function (501),
• a Media Gateway Control Function, MGCF, (501),
• a first network interface (502) to a telecommunication network for receiving call setup request messages,
• characterized in that the NGN (500) comprises
• a second network interface (503) to a telecommunication network for sending IMS type setup request messages,
• a combined database node interface (504) to a combined database node comprising a Home Location Register, HLR, and a Home Subscriber Server, HSS, for requesting routing information and for receiving a response message,
• a processor (505) for determining based on the received response message an address for routing the IMS type call setup request message to the destination node in the IMS network.

A method for supporting setting up a call from a non-Internet Protocol Multimedia Subsystem, non-IMS, telecommunication network comprising a Network Gateway Node, NGN, to a destination node in an IMS network, the destination node for serving a called terminal of a subscriber,

• characterized in that
• a combined database node comprises a Home Location Register, HLR, and a Home Subscriber Server, HSS, and interfaces the NGN, the combined database node further comprises a subscriber profile associated with the called terminal and performs the steps of:
• receiving an information request message (300), comprising an identification of the called terminal, for obtaining routing information for supporting the setup of the call,
• determining (301) at least one capability of the NGN and subscriber information from the subscriber profile,
• generating a response message (302) under consideration of the determined at least one capability of the NGN and the determined information from the subscriber profile,
• sending the response message (303) to the NGN.

A combined database node (600) for supporting setting up a call from a non-Internet Protocol Multimedia Subsystem, non-IMS, telecommunication network comprising a Network Gateway Node, NGN, to a destination node in an IMS network, the destination node for serving a called terminal of a subscriber, the combined database node comprising:

• means (601) for receiving an information request message comprising an identification of the called terminal, for requesting and obtaining routing information,
• characterized in that the combined database node comprises
• a Home Location Register, HLR, (602) and a Home Subscriber Server, HSS, (602),
• means (603) for determining at least one capability of the NGN,
• means (603) for generating a response message under consideration of the determined at least one capability of the NGN,
• means (601) for sending the response message to the NGN.