Media Gateway Control（MGC）：

lResponsible for maintaining the connecting and controlling status of media channel in MGW.

Media Gateway（MGW）：

lResponsible for media streams exchanging and format-converting. For example, MGW convert
the messages format transmitted in TDM bearer to other formats which can be transmitted in IP network.

lATM or IP is provided in physical connection on Mc interface.

lThe Mc interface provides the capabilities of the static and dynamic resources for the MSC Server (GMSC Server) controlling the various transmission modes (IP/ATM/TDM) in the MGW in the call processing procedure, such as terminal property, terminal connection switching relationship, MGW borne media streams.

lThe Mc interface also provides the call independent MGW status maintenance and
management capability.

good description