Capability negotiation in a telecommunications network

A Media Gateway Controller of a telecommunications system wherein Call Control and Bearer Control levels are controlled by separate protocols, the Media Gateway Controller comprising:

• means for receiving a capability preference or prioritised list of preferences from a peer Media Gateway Controller, where said capability preference or prioritised list of preferences relate to a connection to be set-up over the telecommunications system;
• means for communicating with a Media Gateway associated with the Media Gateway Controller to determine the availability of the received preference(s) at the Media Gateway;
• and
• means for returning a capability preference acceptance message to said peer Media Gateway Controller in dependence upon the determined availability at the Media Gateway.

A Media Gateway of a telecommunications system wherein Call Control and Bearer Control levels are controlled by separate protocols, the Gateway comprising:

• means for receiving a capability preference or prioritised list of preferences from a Media Gateway Controller, wherein said capability preference or prioritised list of preferences relate to a connection to be set-up over the telecommunications system;
• means for selecting a preference on the basis of the availability of the preferences at to Media Gateway;
• and
• means for sending the selected preference to said Media Gateway Controller.

A method of setting-up a speech call connection in a telecommunications system where the Call Control protocol is independent of the transport mechanism, the method comprising:

• negotiating a first speech codec between an originating signalling point of the system and a first terminating signalling point;
• establishing a call connection over the transport mechanism between the originating signalling point and said first terminating signalling point in dependence upon said first speech codec;
• subsequently negotiating a second, different speech codec between said first terminating signalling point and a second, new terminating signalling point;
• notifying the originating signalling point of the second speech codec;
• establishing a call connection between the originating signalling point and said second terminating signalling point wherein said first terminating signalling point acts as an intermediate signalling point and wherein the first mentioned call connection is modified if necessary to support said second speech codec.

A telecommunications system in which the Call Control protocol is independent of the transport mechanism, the system comprising:

• means for negotiating a first speech codec between an originating signalling point of the system and a first terminating signalling point;
• means for establishing a call connection over the transport mechanism between the originating signalling point and said first terminating signalling point in dependence upon said first speech codec;
• means for subsequently negotiating a second, different speech codec between said first terminating signalling point and a second, new terminating signalling point;
• means for notifying the originating signalling point of the second speech codec;
• and
• means for establishing a call connection between the originating signalling point and said second terminating signalling point wherein said first terminating signalling point acts as an intermediate signalling point and wherein the first mentioned call connection is modified if necessary to support said second speech codec.

A signalling point of a telecommunications network in which the Call Control protocol is independent of the transport mechanism, the signalling point comprising:

• processing means for negotiating a first speech codec with a first terminating signalling point;
• means for establishing a call connection over the transport mechanism between the originating signalling point and said first terminating signalling point in dependence upon said first speech codec;
• means for receiving a notification of a second speech codec which has been negotiated between said first terminating signalling point and a second, new terminating signalling point;
• and
• means for modifying the first mentioned call connection if necessary to support said second speech codec.