Methods, network control nodes and communication devices for routing signalling requests in a communication system

A method performed by a visiting network control node for routing a signaling request in a communication system comprising a home communication network and a visiting communication network, the signaling request originating from a communication device subscribing to the home communication network and having a home subscriber identification (ID), the communication device further being registered to the visiting communication network with a local subscriber ID different from the home subscriber ID, the local subscriber ID being associated with the home subscriber ID, the method comprising:

• receiving the signaling request from the communication device, the signaling request comprising the local subscriber ID;
• identifying that the received local subscriber ID is associated with a first network control node to which the home network is connected, and
• sending the signaling request comprising the local subscriber ID to the first network control node, wherein the method further comprising, before the communication device is registered to the visiting communication network:
• providing the local subscriber ID to the communication device, wherein the visiting network control node previously received the local subscriber ID to the communication device from the first network control node.

A method performed by a communication device for communicating in a communication system comprising a home communication network, a first network control node, and a visiting communication network, the communication device subscribing to the home communication network and having a home subscriber identification (ID), and contacting the visiting communication network using its home subscriber ID, the method comprising:

• receiving a local subscriber ID from the visiting communication network, for communication in the visiting communication network, the local subscriber ID being associated with the home subscriber ID, wherein the visiting communication network previously received the local subscriber ID from the first network control node,
• changing from the home subscriber ID to the local subscriber ID,
• registering to the visiting communication network using the local subscriber ID, and
• sending a signaling request to the visiting communication network comprising the local subscriber ID.

A first network control node for routing a signaling request in a communication system comprising a home communication network and a visiting communication network, the signaling request originating from a communication device subscribing to the home communication network and having a home subscriber identification (ID), the communication device being registered to the visiting communication network with a local subscriber ID different from the home subscriber ID, the local subscriber ID being associated with the home subscriber ID, the first network control node comprising a processor and a memory, said memory containing instructions executable by said processor whereby said first network control node is operative to:

• receive the signaling request originating from the communication device, the signaling request comprising the local subscriber ID;
• detect that the local subscriber ID is associated with the home subscriber ID;
• replace, in the signaling request, the local subscriber ID with the home subscriber ID;
• and
• send the signaling request comprising the home subscriber ID to a subscriber database of the home network;
• wherein the first network control node is before the communication device is registered to the visiting communication network further operative to:
• receive a connection attempt from the communication device, the connection attempt comprising the home subscriber ID;
• in response to the reception of the connection attempt, link the home subscriber ID to the local subscriber ID;
• and
• provide the local subscriber ID to the communication device.