Voip; Mgcp - Zhone MXK Hardware Installation Manual

MXK

VoIP

MGCP

16
MxK Hardware Installation Guide
Voice over IP, also known as Internet Telephony, supports full duplex
transmission of voice traffic over IP networks. The MXK supports Media
gateway control protocol (MGCP) and Session Initiation Protocol (SIP).
Media gateway control protocol (MGCP) provides the means to interconnect
a large number of IP telephony gateways. MGCP assumes that a call agent
(CA) performs the intelligence of all call-control operations and that a media
gateway (MG) carries out all media processing and conversion.
MGCP provides an internetworking control system to control telephony
gateways from external call control elements are referred to as call agents. A
telephony gateway is a network element that provides conversion between the
audio signals carried on telephone circuits and data packets carried over the
Internet or over other packet networks.
MGCP assumes a call control architecture in which the call control
"intelligence" is outside the gateways and handled by external call control
elements. The MGCP assumes that these call control elements, or Call
Agents, will synchronize with each other to send coherent commands to the
gateways under their control. MGCP does not define a mechanism for
synchronizing Call Agents. MGCP is, in essence, a master/slave protocol,
where the gateways are expected to execute commands sent by the Call
Agents.
MGCP assumes a connection model constructed of endpoints and
connections. Endpoints are sources or sinks of data and could be physical or
virtual.
Examples of physical endpoints are:
•
An interface on a gateway that terminates a trunk connected to PSTN
switch (for example, a Class 5 or Class 4 switch). A gateway that
terminates trunks is called a trunk gateway.
•
An interface on a gateway that terminates an analog POTS connection to
a phone, key system, PBX, etc. A gateway that terminates residential
POTS lines (to phones) is called a residential gateway.
•
An example of a virtual endpoint is an audio source in an audio-content
(media) server.
Creation of physical endpoints requires hardware installation, while creation
of virtual endpoints can be done in software.
Connections may be either point-to-point or multipoint. A point-to-point
connection is an association between two endpoints with the purpose of
transmitting data between these endpoints. Once this association is
established for both endpoints, data transfer between these endpoints can take
place.