Media Gateway Control Protocol (MGCP), also known as IETF RFC 2705, defines
a centralized architecture for creating multimedia network applications,
including VoIP.
H.248 is the result of a joint collaboration between the
ITU-T and the Internet Engineering Task Force (IETF). H.248 is also referred to
as IETF RFC 2885 and as the Multimedia Gateway Control Protocol (Megaco). H.248
also defines a centralized architecture for creating multimedia applications.
In many ways, H.248 builds on and extends MGCP.
MGCP and H.248/Megaco
were designed to provide architecture in which call control and services could
be centrally added to a VoIP network. An architecture using these protocols
closely resembles the existing PSTN architecture and services.
MGCP and
H.248/Megaco define most aspects of signaling using a model called packages.
These packages define commonly used functionality, such as PSTN signaling,
line-side device connectivity, and features such as transfer and hold. SDP is
also used for capabilities exchange.
In a centralized architecture, MGCP
and H.248/Megaco allow companies to build large-scale networks that are
scalable, resilient, and redundant. It provides mechanisms for interconnecting
with other VoIP networks and for adding intelligence and features to the call
agent.