CHAPTER 13 Gateway Control Protocols

Media Gateway Control Protocol: MGC: Media Gateway Controller MG: Media Gateway Master/Slave relationship MG handles: Time-division Multiplexing (TDM) into Real-time Transport Protocol (RTP)/Real-time Transport Control Protocol (RTCP) Intelligence resides in the MGC MGC handles all call signaling MGCP messages carried by User Datagram Protocol

Media Gateway Control Protocol: Uses Session Description Protocol (SDP) to describe media sessions Call agents use SDP to provision endpoints with: IP Addresses UDP port Audio media: (Specifies audio media and codec)

Media Gateway Control Protocol:

Endpoints can either Sink or Source data Endpoints are identified by an endpoint identifier Domain Name Local Name Connections are either point-to-point or multipoint Commands are composed of a command and a mandatory response 

Media Gateway Control Protocol: Basic Call Control Commands: Create Connection (CRCX) Modify Connection (MDCX) Delete Connection (DLCX) Advanced Call Control Commands: Notification request (RQNT) Notification (NTFY) Management Commands Audit Connection (AUCX) Audit Endpoint (AUEP) Restart in Progress (RSIP) Endpoint Configuration (EPCF)

Media Gateway Control Protocol: Create Connection (CRCX) Call ID: Unique Call Identifier Notify Entity (N): Where to send notifications Local Connection Options (L): Encoding, Packetization, Bandwidth, Type of Service…. Mode (M): Full duplex, Receive only, Send only, Inactive and Loopback Remote Connection Description (RC): Connection description for the remote side

Media Gateway Control Protocol: Modify Connection (MDCX) Encoding Scheme Packetization Period Echo Cancellation Connection Activation Connection Deactivation

Media Gateway Control Protocol: Delete Connection (DLCX) Terminates a Connection Places the endpoint into Inactive mode Provides Statistical Information

Media Gateway Control Protocol: Notification Request (RQNT) Request Events (R)  Fax and Modem Tones  Continuity Tones and Detection  On-hook and Off-hook Transition  Flash hook  Channel-associated Signaling (CAS)  Wink  DTMF

Media Gateway Control Protocol: Notification Request (RQNT) Signal Requests (S)  Ringing  Distinctive Ring  Ring Back  Dial  Intercept  Busy  Answer  Call Waiting  Off-hook warning  Continuity tones

Media Gateway Control Protocol: Notification Request (RQNT) Signal Requests (S) Tones: 1.On/Off (OO) 2.Time-out (TO) 3.Brief (BR)

Media Gateway Control Protocol: Notification Request (RQNT) Signal Requests (S) Tones:

Media Gateway Control Protocol: Notification Request (RQNT) Notification Entity (N): Where to send notifications Request Identifier (X): Correlates the Notification Request with the notification

Media Gateway Control Protocol: Notification (NTFY) Notified Entity (N): Where to send notification Request Identifier (X): Correlates the request to the notification Observed Events (O): List of events that the gateway detected

Media Gateway Control Protocol: Audit Endpoint (AUEP) Endpoint List: Identifies the endpoint Notify Entity (N): Whom to notify Requested Events (R):List of currently requested events Digit Map Signal Request (S): List of currently applied signal requests Request Identifier (X): Identification for the last Notify Request received Connection Identifier (I): Current connections for an endpoint Detect Events (T): Currently detected events in Quarantine mode Local Connection Options (L): A list of current values

Media Gateway Control Protocol: Audit Connection (AUCX) Call ID: Unique Identifier to the call Notify Entity (N): Whom to notify Local Connection Options (L): Options currently being applied Mode (M): Current mode of the connection Remote Connection Descriptor (RC): The remote SDP being used Local Connection Descriptor (LC): Gateway used for the connection Connection Parameters (P): Current value of parameters at the audited connection

Media Gateway Control Protocol: Restart In-Progress (RSIP) Endpoint ID: Unique Identifier Restart Method (RM)  Graceful  Forced  Restart  Disconnected Restart Delay (RD): Delay in seconds

Media Gateway Control Protocol: Endpoint Configuration (EPCF) Specify the encoding of signals International circumstances that use both u-law and a-law Bearer Information (B): Identifies encoding technique

Media Gateway Control Protocol: Response Messages

Media Gateway Control Protocol: Response Messages

Media Gateway Control Protocol: Call Flows Basic

Media Gateway Control Protocol: Call Flows Trunking

Media Gateway Control Protocol: Advanced MGCP Features  Events and event packages  Digit Maps  Embedded Notification Requests  Non-IP bearer networks

Media Gateway Control Protocol: Event Packages Basic

Media Gateway Control Protocol: Event Packages Endpoint

Media Gateway Control Protocol: Digit Maps Collects digit events (dialed) Digit-by-digit RQNT NTFY

Media Gateway Control Protocol: Embedded Notifications Requests R:hd(E(R[0-9]))

End of Chapter 13