Capability negotiation in a telecommunications network

摘要

Node A represents an originating signalling point to which a calling party is connected whilst node C represents a terminating signalling point to which a called party is connected. Each of the signalling points comprises a call control level and a bearer control level. The bearer control level, comprising a bearer network such as an Internet Protocol (IP) network or an ATM network. When a calling party initiates a call, the originating signalling point generates a list of possible options relating to the capabilities of the originating signalling point which must be negotiated with the terminating signalling point node C. Node A sends a message to node C specifying the list of options in order of preference. Node C selects the preferred option and signals its choice to node A. Capabilities which may be negotiated in this way include the choice of a suitable speech codec for the call or security capabilities such as voice ciphering or data encryption.