Method for the routing of multimedia communication related signaling in a communication system

1. A method, comprising:

receiving a signaling message at a first network node from a proxy network node, said signaling message providing a first private user identity and a first public user identity;

computing a first key from said first private user identity;

matching said first key to at least one key range, each said at least one key range being associated with a network node;

determining a second network node by detecting that said first key belongs to the key range of said second network node;

providing said signaling message to said second network node;

obtaining data associated with said first private user identity in said second network node;

extracting said first public user identity from said signaling message in said second network node;

computing a second key from said first public user identity;

routing said signaling message to a third network node identified with said second key;

obtaining data associated with said first public user identity in said third network node;

registering a registration status of said first public user identity as active in said third network node;

registering an identity of said proxy network node in said data associated with said first public user identity;

receiving a session establishment message at a fourth network node, said session establishment message comprising said first public user identity;

determining a third key from said first public user identity in said fourth network node;

routing said session establishment message to said third network node identified with said third key;

receiving said session establishment message at said third network node;

determining said registration status of said first public user identity; and

in response to said determination, transmitting said session establishment message to said proxy network node.

2. The method according to claim 1 , the method further comprising:

determining at least one second public user identity associated with said first private user identity in said second network node;

determining routing keys for each said at least one second public user identity; and

routing the signaling message to at least one fifth network node identified with said routing keys.

3. The method according to claim 1 , the method further comprising:

determining a fifth network node having a key range closest to said first key; and

sending said signaling message to said fifth network node.

4. The method according to claim 1 , the method further comprising:

receiving said signaling message at said proxy network node from an end device via an access network; and

transmitting said signaling message to said first network node.

5. The method according to claim 1 , wherein said signaling message is a Session Initiation Protocol message.

6. A system, comprising:

a first network node configured

to receive a signaling message from a proxy network node, said signaling message providing a first private user identity and a first public user identity,

to compute a first key from said first private user identity,

to match said first key to at least one key range, each said at least one key range being associated with a network node,

to determine a second network node by detecting that said first key belongs

to the key range of said second network node, and

to provide said signaling message to said second network node;

said second network node configured

to obtain data associated with said first private user identity,

to extract said first public user identity from said signaling message, to compute a second key from said first public user identity, and

to route said signaling message to a third network node identified with said second key;

said third network node configured

to register a registration status of said first public user identity as active, obtaining data associated with said first public user identity,

to register an identity of said proxy network node in said data associated with said first public user identity,

to receive said session establishment message,

to determine said registration status of said first public user identity, and in response to said determination, to transmit said session establishment message to said proxy network node,

a fourth network node configured

to receive a session establishment message, said session establishment message comprising said first public user identity,

to determine a third key from said first public user identity, and

to route said session establishment message to said third network node identified with said third key.

7. The system according to claim 6 , the system further comprising:

said second network node configured to determine at least one second public user identity associated with said first private user identity, to determine routing keys for each said at least one second public user identity and to send said signaling message for routing in said system to at least one fifth network node identified with said routing keys; and

said at least one fifth network node.

8. The system according to claim 6 , the system further comprising:

said second network node configured to determine a fifth network node having a key range closest to said first key and to send said signaling message to said fifth network node.

9. The system according to claim 6 , the system further comprising:

an access network; and

said proxy network node configured to receive said signaling message from an end device via said access network and to transmit said signaling message to said first network node.

10. The system according to claim 6 , wherein signaling message is a Session Initiation Protocol message.

11. An apparatus, comprising:

a processor configured

to receive a signaling message, said signaling message providing a first private user identity and a first public user identity,

to compute a first key from said first private user identity,

to match said first key to at least one key range, each said at least one key range being associated with a network node,

to determine a remote network node by detecting that said first key belongs to the key range of said remote network node,

to obtain data associated with said first private user identity,

to extract said first public user identity from said signaling message,

to compute a second key from said first public user identity,

to route said signaling message with said second key,

to register a registration status of said first public user identity as active,

to obtain data associated with said first public user identity,

to register an identity of a proxy network node in said data associated with said first public user identity,

to receive a session establishment message, said session establishment message comprising said first public user identity,

to determine a third key from said first public user identity,

to route said session establishment message with said third key,

determine said registration status of said first public user identity, and

in response to said determination, to transmit said session establishment message to said proxy network node.

12. An apparatus, comprising:

means for receiving a signaling message, said signaling message providing a first private user identity and a first public user identity;

means for computing a first key from said first private user identity;

means for matching said first key to at least one key range, each said at least one key range being associated with a network node;

means for determining a remote network node by detecting that said first key belongs to the key range of said remote network node;

means for obtaining data associated with said first private user identity;

means for extracting said first public user identity from said signaling message;

means for computing a second key from said first public user identity;

means for routing said signaling message with said second key;

means for registering a registration status of said first public user identity as active;

means for obtaining data associated with said first public user identity;

means for registering an identity of a proxy network node in said data associated with said first public user identity;

means for receiving a session establishment message, said session establishment message comprising said first public user identity;

means for determining a third key from said first public user identity;

means for routing said session establishment message with said third key;

means for determining said registration status of said first public user identity; and

means for, in response to said determination, transmitting said session establishment message to said proxy network node.

13. A computer program embodied on a computer readable medium, when executed on a data-processing system, the computer program being configured to perform:

receiving a signaling message, said signaling message providing a first private user identity and a first public user identity;

computing a first key from said first private user identity;

matching said first key to at least one key range, each said at least one key range being associated with a network node;

determining a remote network node by detecting that said first key belongs to the key range of said remote network node;

obtaining data associated with said first private user identity;

extracting said first public user identity from said signaling message;

computing a second key from said first public user identity;

routing said signaling message with said second key;

obtaining data associated with said first public user identity in said third network node;

registering a registration status of said first public user identity as active;

registering an identity of a proxy network node in said data associated with said first public user identity;

receiving a session establishment message, said session establishment message comprising said first public user identity;

determining a third key from said first public user identity;

routing said session establishment message with said third key;

determining said registration status of said first public user identity; and

in response to said determination, transmitting said session establishment message to said proxy network node.

14. The computer program according to claim 13 , wherein said computer readable medium is a removable memory card.

15. The computer program according to claim 13 , wherein said computer readable medium is a removable memory device.

16. The computer program according to claim 13 , wherein said computer readable medium is a magnetic disk, a holographic memory or an optical disk.