Routing a call

1. A method of routing an incoming call involving a calling party and a called party in a telecommunications network via a selected media routing path of a plurality of different media routing paths, each of the media routing paths being for communicating media data to, from, or to and from, at least one calling party device associated with the calling party and at least one called party communication device associated with the called party, the method comprising:

a call control system in the telecommunications network receiving, from the at least one calling party device, a call setup request directed to the called party;

the call control system receiving data derived from a media quality test procedure for a given media routing path prior to the call being established between the calling party and the called party, the media quality test procedure including media test data being communicated via the given media routing path and the media test data being analyzed to determine whether the given media routing path supports communication of media data associated with the call with an acceptable media quality; and

the call control system selecting, prior to the call being established between the calling party and the called party, a preferred media routing path from the plurality of different media routing paths for said communicating media data associated with the call to, from, or to and from, one or more of the at least one called party communication devices on the basis of at least the received data derived from the media quality test procedure,

wherein the media quality test procedure comprises a media loopback test being performed, and

wherein the media loopback test comprises transmission and reception of a SIP INVITE message with Session Description Protocol (SDP) indicating a request for a loopback connection, and transmission and reception of a SIP OK message with an SDP offer identifying a loopback media port.

2. The method according to claim 1 , wherein said selecting the given media routing path from the plurality of different media routing paths is based at least on pre-existing preferred media routing path selection data.

3. The method according to claim 1 , wherein at least one of the plurality of different media routing paths includes a cellular access network.

4. The method according to claim 1 , wherein at least one of the plurality of different media routing paths includes a circuit-switched network.

5. The method according to claim 1 , wherein at least one of the plurality of different media routing paths includes a packet-switched network.

6. The method according to claim 1 , further comprising the call control system performing the media quality test procedure.

7. The method according to claim 1 , wherein the media quality test procedure is performed by one or more given called party communication devices of the at least one called party communication devices.

8. The method according to claim 7 , further comprising transmitting one or more messages that are operable to cause the one or more given called party communication devices to perform the media quality test procedure for the given media routing path.

9. A method of controlling a communication device, in a telecommunications network comprising a plurality of different media routing paths, each of the media routing paths being for communicating media data associated with a call involving the communication device and at least one remote party device associated with a remote call party to, from, or to and from, one or more entities in the telecommunications network, the method comprising:

detecting one or more predetermined triggers prior to originating the call, wherein the one or more predetermined triggers comprise expiry of a media quality test time period;

initiating a media quality test procedure for a given media routing path prior to originating the call, the media quality test procedure including media test data being communicated via the given media routing path and the media test data being analyzed to determine whether the given media routing path supports communication of media data associated with the call with an acceptable media quality; and

selecting, prior to the call being established between the communication device and the at least one remote party device, a preferred media routing path from the plurality of different media routing paths for communicating media data associated with the call on the basis of at least the media quality test procedure,

wherein the media quality test procedure comprises a media loopback test being performed, and

wherein the media loopback test comprises transmission and reception of a SIP INVITE message with Session Description Protocol (SDP) indicating a request for a loopback connection, and transmission and reception of a SIP OK message with an SDP offer identifying a loopback media port.

10. The method according to claim 9 , further comprising initiating the media quality test procedure in response to detecting the one or more predetermined triggers.

11. The method according to claim 9 , wherein the one or more predetermined triggers is associated with originating the call.

12. The method according to claim 9 , wherein the one or more predetermined triggers includes an attempt to originate the call.

13. The method according to claim 9 , wherein the one or more predetermined triggers includes activity that leads to a call origination attempt.