MGCP Media Gateway Control Protocol

In this article I describe the MGCP Media Gateway Control Protocol in computer networking for CCNA Exam. Media Gateway Control Protocol is a call control protocol which is used in VOIP communication. VOIP is Voice over internet protocol which provide the voice communication on TCP/IP network or internet. Telephone and smart phones are now a very common thing. The normal phone communication on the radio waves which do not required any IP address or internet connectivity. In today scenario the voice communication shifted on the IP based system. A user use the voice communication similar to data communication on internet. Media Gateway Control Protocol provides the facility to make voice calls between different clients on internet or WAN.

MGCP Media Gateway Control Protocol provides the reformation of normal electronic voice communication to the IP based voice communication. The TCP/IP network provide the data transfer between the clients on the internet. The voice communication can be done in the same way like data transfer in the TCP/IP network. The voice changed in the form of data packets and transferred between different devices like IP Phone. We can say the voice transformed in the form of digital data and routed from the routers in similar way to data communication. A central call agent controls the voice transmission in the TCP/IP network. So before understand the Media Gateway Control Protocol let’s take a look on the VOIP.

VOIP Voice Over Internet Protocol

VOIP provide the feature of voice calls over the internet or IP network. The ordinary voice call terminology replaced by the IP network communication system. The technology is simple as sending a message over the internet. In case of VOIP the voice breaks in the form of data packets and routed via router in the TCP/IP network. At the receiver end the data packets reconstruct to produce the voice. IP phone used in place of ordinary analog telephones. A Fix IP address assigned to each IP phone the user do not need to remember the IP address. A simple series of numbers can be assigned against the IP address of the IP phones.

You can understand it in a simple way like video conferencing over internet. During video conferencing both the end users can see each other with live stream along with voice communication. Similarly the VOIP protocol enable the IP phones to communicate with each other over the TCP/IP network or internet.

VOIP terminology for MGCP Media Gateway Control Protocol

VOIP terminology involves some common terms related to VOIP communication over the TCP/IP network or internet. The first term related to VOIP is Session Initiation Protocol SIP. SIP initiated the sessions between different clients to provide connectivity so the clients can make VOIP call with each other. The connection can be initiate, modify or terminated by the SIP protocol.

The connectivity provides by the telephony like OFC, ADSL or Leased line between the users. Generally we can say the users need an internet connection to make a VOIP call with each other. CODEC are used to compress the VOIP data on the network to save the bandwidth. CODEC works on both ends of VOIP communication users. Some protocols like DHCP also can be used to allot the IP address to the IP phone in the network. These are optional things.

MGCP Media Gateway Control Protocol architecture

MGCP belongs to RFC 2805. The MGCP works on the master slave operation in the network. There is a central call agent known as call control agent which is works like a Media Gateway Controller in the network. The media control agent decide whether the users should be connected or not on the TCP/IP network. There may be multiple call agents available which control the MGCP commands in the network. All the call agents in case of multiple call agents understand the status of devices using VOIP in the network. Media Gateway Control Protocol used by call agents to monitor the data flow from media gateway. Multiple call agents can configure a media gateway by using Media Gateway Control Protocol.

MGCP Media Gateway Control Protocol structure

MGCP is acronym of Media Gateway Control Protocol. The MGCP used in VOIP voice over internet protocol in telecommunication systems. The Media Gateway Control Protocol use to establish media session between two multimedia end points. MGCP provides Control between audio signals in a network or internet. MGCP used in telephone circuits in which the audio signal travels in the form of packet. Media gateway controller also called call agent.

Media Gateway Control Protocol can used as gateway for VOIP packets in a network. Call agent create and modify connections on media gateways to establish sessions. Call agent can control and generate audio signals in a network with the help of MGCP. Media Gateway Control Protocol is a command-control text-base protocol.

MGCP identify the call agent, the media gateway and session between endpoints. A media gateway can be engaged in multiple connections. Multiple endpoints can host in a media gateway. Call waiting is the example of multiple connection on an endpoint. Media gateway use port number 2427 while the call agents use port number 2727.

Commands and codes are used to control the media gateways’ use messages containing the commands and response code. Mostly UDP protocol is used for VOIP. Some time you feel that voice cuts during a telephone call, but call is not disconnected. This is because of UDP protocol used in VOIP in a network. UDP protocol do not retransmit the data packet if the data packets lost during transmission in the network. Many times you feel the missed voice does not come again, this is due the use of UDP protocol in the VOIP communication. UDP port 2427 is used to forward the Media Gateway Control Protocol commands and messages on the network.

Commands used for MGCP – Media Gateway Control Protocol

MGCP protocol used nine standard commands. These commands are the combination of four letters. AUEP, AUCX, CRCX, DLCX, EPCF, MDCX, NTFY, RQNT, and RSIP are nine commands. Response is three-digit code. Response code tells about the result of an event.

Nine command meaning can be identify by its full forms. AUEP is the acronym of Audit Endpoint which tells the present status of endpoints. AUCX is acronym of Audit connection which is use to get status of a connection. CRCX is acronym of Create Connection, it is use to create connections between two media gateways. DLCX is acronym of Delete connection, it is use to vanish a connection between media gateways. EPCF is acronym of endpoint configuration, it is use to configure the end points in a network. MDCX is acronym of Modify connection which is use to alter the connection. NTFY is acronym for Notify, notifications used this acronym. RQNT is acronym of request for notification, it is use to get latest notification from media gateway. RSIP is acronym for restart in progress, it means the connection is restarted again and in progress. All commands of Media Gateway Control Protocol explained in detail below.

• Audit Endpoint (AUEP)- The MGCP Media Gateway Control Protocol sends this message to gateway to gather the information about the end point or clients.
• Audit Connection (AUCX): The MGCP Media Gateway Control Protocol use this message to gather information related to the connections.
• Create Connection (CRCX): The MGCP Media Gateway Control Protocol use this command to establish the connection between the endpoint devices or clients.
• Delete Connection (DLCX): The MGCP Media Gateway Control Protocol use this command to delete and existing connection between end users.
• Endpoint Configuration (EPCF): The MGCP Media Gateway Control Protocol use this message to specify the encoding signal.
• Modify Connection (MDCX): The MGCP Media Gateway Control Protocol use this command or message to modify and existing connection between different endpoint users.
• Notification (NTFY): The MGCP Media Gateway Control Protocol use this command to get the notificaiton about anything misshapp between the different users.
• Notification Request (RQNT): The MGCP Media Gateway Control Protocol sends this message to gateway to notify about off-hook and on-hook.
• Restart In Progress (RSIP): The MGCP Media Gateway Control Protocol use this command when the connection lost between the clients.

In this article I describe the MGCP Media Gateway Control Protocol in computer network for CCNA Exam. I hope you found this article helpful. For any query or suggestions on this article you may drop a comment below or contact us. Your suggestions are always welcome by us.