Signaling gateway

1. A signaling gateway for passing messages from a first network to an application server process provided on a second network, the messages comprising a transaction identifier, wherein

the transaction identifier comprising a set of bits utilized by a transmission protocol, and a set of remaining bits comprising a part;

the signaling gateway is configured to receive an initial message from a calling entity and read the transaction identifier within the initial message,

to identify the application server process from the part of the transaction identifier,

to forward the initial message to the application server process,

to receive a continuation message from the application server process, in response to the application server process receiving the initial message, the continuation message including the transaction identifier,

to modify the transaction identifier within the continuation message as a modified transaction identifier, and

to forward the continuation message to the calling entity,

wherein the modified transaction identifier includes at least a part identifying the application server process and a further part identifying an application server prior to forwarding the continuation message to the calling entity, and the set of remaining bits of the transaction identifier comprises the part and the further part.

2. A signaling gateway according to claim 1 , wherein the part identifying the application server process includes most significant bits of the modified transaction identifier.

3. A signaling gateway according to claim 2 , configured to receive a further message from the calling entity, the further message including the modified transaction identifier, wherein the signaling gateway is configured to remove the part identifying the application server process and the further part identifying the application server from the transaction identifier of the further message prior to forwarding the further message to the application server process.

4. A signaling gateway according to claim 1 , wherein the initial message further comprises a routing key and the signaling gateway is configured to forward the initial message to the application server process in accordance with the routing key.

5. A signaling gateway according to claim 1 , wherein the first network comprises an SS7 network and the second network comprises an IP network.

6. A signaling gateway according to claim 5 , wherein the messages from the first network are in accordance with a TCAP protocol.

7. An application server configured to

receive an initial message from a calling entity forwarded by a signaling gateway,

to generate a continuation message, in response to receiving the initial message, the continuation message including a transaction identifier comprised of a set of bits utilized by a transmission protocol

to modify the transaction identifier within the continuation message as a modified transaction identifier, wherein the modified transaction identifier includes a set of remaining bits comprising at least a part identifying an application server process and a further part identifying the application server, and

to forward the continuation message to the signaling gateway.

8. A method of passing messages from a first network to an application server process provided on a second network, the messages comprising a transaction identifier comprised of a set of bits utilized by a transmission protocol and a set of remaining bits including a part, comprising the steps of:

receiving by a signaling gateway an initial message from a calling entity and reading the transaction identifier within the initial message,

identifying by the signaling gateway the application server process from the part of the transaction identifier;

forwarding by the signaling gateway the message to the application server process;

receiving by the signaling gateway a continuation message from the application server process, in response to the application server process receiving the initial message, the continuation message including the transaction identifier;

to modify the transaction identifier within the continuation message as a modified transaction identifier; and

forwarding by the signaling gateway the continuation message to the calling entity,

wherein the modified transaction identifier includes at least a part identifying the application server process and a further part identifying an application server prior to forwarding the continuation message to the calling entity, and the set of remaining bits of the transaction identifier comprises the part and the further part.

9. A method according to claim 8 , wherein the modified transaction identifier is modified such that most significant bits of the modified transaction identifier identify the application server process.