This object specifies which protocol that the media gateway
should use to communicate with MGC (Call Agent) when it
try to set up the call.
The value of this object is the same as the value of object
cMediaGwProtocolIndex from protocol table
(cMediaGwProtocolTable).
If the value of cXgcpMgcConfigMgcGrpNum is non-zero, this
object will be ignored because the protocol will be
determined by the MGC group.
The initial value is 1, means the system should have at
least one default protocol between the gateway and MGC
created in the cMeidaGwProtocolTable when the system is
initialized.