Network-based Call Signaling
Network-based Call Signalling[1] is a call signaling protocol.
The call signaling protocol is one layer of the overall PacketCable suite of specifications and relies upon companion protocol specifications to provide complete end-to-end PacketCable functionality.
Network-based Call Signaling,[2] based on the Media Gateway Control Protocol (MGCP[3]), is the VOIP signaling protocol adopted by the CableLab as a standard for PacketCable embedded clients, which is a network element that provides:
- Two or more traditional analog (RJ11) access lines to a voice-over-IP (VoIP) network.
- Optionally, one or more video lines to a VoIP network
MGCP is a call signaling protocol for use in a centralized call control architecture, and assumes relatively simple client devices. The call signaling protocol is one layer of the overall PacketCable suite of specifications and relies upon companion protocol specifications to provide complete end-to-end PacketCable functionality.
NCS provides a PacketCable profile of an application programming interface (MGCI[4]), and a corresponding protocol (MGCP) for controlling voice-over-IP (VoIP) embedded clients from external call control elements. MGCI functions provide for connection control, endpoint control, auditing, and status reporting. They each use the same system model and the same naming conventions.
The NCS profile of MGCP has been modified from the MGCP 1.0 in the following ways:
- The NCS protocol only aims at supporting PacketCable-embedded clients. Functionality present in the MGCP 1.0 protocol, which was superfluous to NCS, has been removed.
- The NCS protocol contains extensions and modifications to MGCP. However, the MGCP architecture, and all of the MGCP constructs relevant to embedded clients, are preserved in NCS.
- The NCS protocol contains minor simplifications from MGCP 1.0 ᾍ ᾅ Ἃ ἃ ᾋ ᾃ Ἇ