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Copyright © 2009 Red Hat, Inc.
Abstract
MGCP Demo is Media Gateway Controller Application demonstrating the usage of MGCP RA
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If you find a typographical error in this manual, or if you have thought of a way to make this manual better, we would love to hear from you! Please submit a report in the the Issue Tracker, against the product Mobicents JAIN SLEE MGCP Demo Example, or contact the authors.
When submitting a bug report, be sure to mention the manual's identifier: JAIN_SLEE_MGCPDemo_EXAMPLE_User_Guide
If you have a suggestion for improving the documentation, try to be as specific as possible when describing it. If you have found an error, please include the section number and some of the surrounding text so we can find it easily.
MGCP assumes a call control architecture where the call control "intelligence" is outside the gateways and handled by external call control elements known as Call Agents. The MGCP assumes that these call control elements, or Call Agents, will synchronize with each other to send coherent commands and responses to the gateways (mdia servers) under their control. If this assumption is violated, inconsistent behavior should be expected. MGCP does not define a mechanism for synchronizing Call Agents. MGCP is, in essence, a master/slave protocol, where the gateways are expected to execute commands sent by the Call Agents.
This example demonstrates how MGCP RA can be used as Media Gateway Call Controller to control the Media Gateway (Media Server)
Prior knowledge of MGCP is necessary to understand this example. To learn about MGCP, look at RFC 3435. Knowledge of MGCP RA is also desired.
Ensure that the following requirements have been met before continuing with the install.
The Example doesn't change the Mobicents JAIN SLEE Hardware Requirements, refer to Mobicents JAIN SLEE documentation for more information.
The Example requires Mobicents JAIN SLEE properly set, with following list of dependencies deployed/started.
Its required that MGCP RA is deployed. The MGCP RA is responsible to fire the MGCP Events corresponding to MGCP Request/Response received from Media Gateway
Its required that SIP11 RA is deployed. The SIP RA is responsible to fire the SIP Events like INVITE, BYE etc received from SIP User Agents
The demo sends MGCP Signals to Media Gateway (Media Server) to play announcements, text-to-speech, initiate conference etc and also requests DTMF events to be notified back to Application. The media part is taken care by Mobicents Media Server; its required that Mobicents Media Server is started before the User dials respective digits to test demo.
This section provides instructions on how to obtain and build the MGCP Demo Example from source code.
Downloading the source code
Subversion is used to manage its source code. Instructions for using Subversion, including install, can be found at http://svnbook.red-bean.com
Use SVN to checkout a specific release source, the base URL is http://mobicents.googlecode.com/svn/tags/servers/jain-slee/2.x.y/examples/mgcp-demo, then add the specific release version, lets consider 2.1.2.FINAL.
[usr]$ svn co http://mobicents.googlecode.com/svn/tags/servers/jain-slee/2.x.y/examples/mgcp-demo/2.1.2.FINAL slee-example-mgcp-demo-2.1.2.FINAL
Building the source code
Maven 2.0.9 (or higher) is used to build the release. Instructions for using Maven2, including install, can be found at http://maven.apache.org
Use Maven to build the deployable unit binary.
[usr]$ cd slee-example-mgcp-demo-2.1.2.FINAL [usr]$ mvn install
Once the process finishes you should have the
deployable-unit
jar file in the
target
directory, if
Mobicents
JAIN SLEE is installed and environment variable
JBOSS_HOME is pointing to its underlying
JBoss Application Server
directory, then the deployable unit jar will
also be deployed in the container.
Similar process as for Section 2.2.1, “Release Source Code Building” , the only change is the SVN source code URL, which is http://mobicents.googlecode.com/svn/trunk/servers/jain-slee/examples/mgcp-demo.
To install the Example simply execute provided ant script
build.xml
default target:
[usr]$ ant
The script will copy the Example's deployable unit jar to
the
default
Mobicents
JAIN SLEE server profile deploy directory, to deploy to
another server profile use the argument
-Dnode=
.
To uninstall the Example simply execute provided ant script
build.xml
undeploy
target:
[usr]$ ant undeploy
The script will delete the Example's deployable unit jar
from the
default
Mobicents
JAIN SLEE server profile deploy directory, to undeploy from
another server profile use the argument
-Dnode=
.
The example is designed to demonstrate the usage of JAIN MGCP API including the MGCP RA. At the same time it also demonstrates various features/capabilities of Mobicents Media Server. MGCP messages are transmitted over UDP. Commands are sent to IP addresses defined in the domain for the endpoint. The responses are sent back to the source address (i.e., IP address and UDP port number) of the commands. The domain name specified for Endpoint can include port number as colon separated value. For example 122.64.4.108:2427
When no port is specified for the endpoint, the commands by default is sent:
by the Call Agents, to the default MGCP port for gateways, 2427.
by the Gateways, to the default MGCP port for Call Agents, 2727.
The MGCP RA bounds the MGCP Stack to IP address and Port specified for jain.mgcp.IP_ADDRESS, jain.mgcp.PORT properties in resource-adaptor-jar.xml for MGCP RA. For further details looks at MGCP RA Documentation.
The Example is composed of 3 Services.
First Service is composed of CallSbb as parent/root listening for SIP INVITE as initial event. IVRSbb, RecorderSbb and TTSSbb are its children.
Second Service is composed of only ConferenceSbb acting as root. Its listening for SIP INVITE too and has lower priority than above Service.
Third Service is composed of only ConfLegSbb acting as root. Its listening for Custom Event fired by ConferenceSbb when the first participant joins the Conference.
CallSbb listens for incoming SIP call and depending on To field of INVITE it creates respective child; Child does further processing of SIP Message.
2010 : If user dialed 2010, IVRSbb child is created. As name suggest IVRSbb is responsible for playing announcement to user and listening for DTMF inputs from user. Depending on which DTMF is dialed by user, corresponding announcement is played again.
2011 : If user dialed 2011, RecorderSbb child is created. As name suggest RecorderSbb is responsible for recording user's voice and playing it back after 30 seconds.
2013 : If user dialed 2013, TTSSbb child is created. TTSSbb sends the text to Mobicents Media Server (MMS) and MMS plays back the speech corresponding to this text to user.
ConferenceSbb is responsible for maintaining Conference. User gets connected to Conference endpoint by dialing 2012 from SIP Phone. If this is the first User joining Conference, ConferenceSbb fires Custom Event that is consumed by ConfLegSbb. Multiple users can dial 2012 and get connected to same Conference endpoint and participate in conference call.
ConfLegSbb is acting as one of the automated leg of Conference. As soon as conference is initiated, this leg of conference will start a back ground music so even if there is only one participant in conference he/she can listen to music that verifies Conference has started.
As explained earlier, the main purpose of this demo is to make developers understand how to use the MGCP API and MGCP RA. Once there is clear understanding of MGCP API and RA, the business logic can be written as required. Let us go to Section 4, where MGCP usage from respective SBB is explained.
The bellow source code is from IVRSbb, it hides SIP related logic and highlights MGCP specific code. In case if you want to look at complete source, please get the source code as explained in Section 2.2.
package org.mobicents.mgcp.demo; ...... public abstract class IVRSbb implements Sbb { public final static String ENDPOINT_NAME = "/mobicents/media/IVR/$"; public final static String JBOSS_BIND_ADDRESS = System.getProperty("jboss.bind.address", "127.0.0.1"); public final static String WELCOME = "http://" + JBOSS_BIND_ADDRESS + ":8080/mgcpdemo/audio/RQNT-ULAW.wav"; ...... private SbbContext sbbContext; ...... // MGCP private JainMgcpProvider mgcpProvider; private MgcpActivityContextInterfaceFactory mgcpAcif; public static final int MGCP_PEER_PORT = 2427; public static final int MGCP_PORT = 2727; private Tracer logger; /** Creates a new instance of CallSbb */ public IVRSbb() { } public void onCallCreated(RequestEvent evt, ActivityContextInterface aci) {....... //SIP Related handling ....... // respond(evt, Response.RINGING); CallIdentifier callID = mgcpProvider.getUniqueCallIdentifier();
this.setCallIdentifier(callID.toString()); EndpointIdentifier endpointID = new EndpointIdentifier(ENDPOINT_NAME, JBOSS_BIND_ADDRESS + ":" + MGCP_PEER_PORT);
CreateConnection createConnection = new CreateConnection(this, callID, endpointID, ConnectionMode.SendRecv);
try { String sdp = new String(evt.getRequest().getRawContent()); createConnection.setRemoteConnectionDescriptor(new ConnectionDescriptor(sdp));
} catch (ConflictingParameterException e) { // should never happen } int txID = mgcpProvider.getUniqueTransactionHandler();
createConnection.setTransactionHandle(txID); MgcpConnectionActivity connectionActivity = null; try { connectionActivity = mgcpProvider.getConnectionActivity(txID, endpointID);
ActivityContextInterface epnAci = mgcpAcif.getActivityContextInterface(connectionActivity); epnAci.attach(sbbContext.getSbbLocalObject()); } catch (FactoryException ex) { ex.printStackTrace(); } catch (NullPointerException ex) { ex.printStackTrace(); } catch (UnrecognizedActivityException ex) { ex.printStackTrace(); } mgcpProvider.sendMgcpEvents(new JainMgcpEvent[] { createConnection });
} ... .... }
| |
New instance of | |
New instance of | |
New instance of | |
Setting the SDP of User Agent. This is not mandatory. If this is set the Connection created on Endpoint on media gateway will
start sending the media (depending on | |
Set a new transaction for this MGCP Request. | |
Create a new | |
Finally send this |
Once the MGCP command reaches Media Gateway, it replies back and MGCP RA will fire corresponding event.
public void onCreateConnectionResponse(CreateConnectionResponse event, ActivityContextInterface aci) {logger.info("Receive CRCX response: " + event.getTransactionHandle()); ...... .... ReturnCode status = event.getReturnCode();
switch (status.getValue()) { case ReturnCode.TRANSACTION_EXECUTED_NORMALLY: this.setEndpointName(event.getSpecificEndpointIdentifier().getLocalEndpointName());
ConnectionIdentifier connectionIdentifier = event.getConnectionIdentifier();
this.setConnectionIdentifier(connectionIdentifier.toString()); String sdp = event.getLocalConnectionDescriptor().toString();
//Send OK to UA with SDP from media gateway ..... ....... //Play Announcement sendRQNT(WELCOME, false);
..... ...... break; default: //CRCX failed at Media Gateway. Take necessary action
..... } }
MGCP RA will fire the | |
| |
If connection created successfully, | |
If connection created successfully, | |
If connection created successfully, | |
Since the RTP connection is established between UA and Media Gateway, | |
If creation of connection failed for some reason indicated by |
Let us see how NotificationRequest
is used to request Media Gateway to play an Announcement
private void sendRQNT(String mediaPath, boolean createActivity) { EndpointIdentifier endpointID = new EndpointIdentifier(this.getEndpointName(), JBOSS_BIND_ADDRESS + ":" + MGCP_PEER_PORT);NotificationRequest notificationRequest = new NotificationRequest(this, endpointID, mgcpProvider .getUniqueRequestIdentifier());
ConnectionIdentifier connectionIdentifier = new ConnectionIdentifier(this.getConnectionIdentifier());
EventName[] signalRequests = { new EventName(PackageName.Announcement, MgcpEvent.ann.withParm(mediaPath), connectionIdentifier) }; notificationRequest.setSignalRequests(signalRequests);
RequestedAction[] actions = new RequestedAction[] { RequestedAction.NotifyImmediately }; RequestedEvent[] requestedEvents = {
new RequestedEvent(new EventName(PackageName.Announcement, MgcpEvent.oc, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Announcement, MgcpEvent.of, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf0, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf1, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf2, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf3, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf4, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf5, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf6, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf7, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf8, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmf9, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmfA, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmfB, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmfC, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmfD, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmfStar, connectionIdentifier), actions), new RequestedEvent(new EventName(PackageName.Dtmf, MgcpEvent.dtmfHash, connectionIdentifier), actions) }; notificationRequest.setRequestedEvents(requestedEvents); notificationRequest.setTransactionHandle(mgcpProvider.getUniqueTransactionHandler()); NotifiedEntity notifiedEntity = new NotifiedEntity(JBOSS_BIND_ADDRESS, JBOSS_BIND_ADDRESS, MGCP_PORT); notificationRequest.setNotifiedEntity(notifiedEntity); if (createActivity) {
MgcpEndpointActivity endpointActivity = null; try { endpointActivity = mgcpProvider.getEndpointActivity(endpointID); ActivityContextInterface epnAci = mgcpAcif.getActivityContextInterface(endpointActivity); epnAci.attach(sbbContext.getSbbLocalObject()); } catch (FactoryException ex) { ex.printStackTrace(); } catch (NullPointerException ex) { ex.printStackTrace(); } catch (UnrecognizedActivityException ex) { ex.printStackTrace(); } } // if (createActivity) mgcpProvider.sendMgcpEvents(new JainMgcpEvent[] { notificationRequest });
logger.info(" NotificationRequest sent"); }
The | |
Create a new | |
The | |
The | |
The | |
Since none of the Signals/Events are fired/detected on Endpoint, Endpoint Activity is not created. The above Events when detected would be fired on Connection Activity. | |
Finally send the request to Media Gateway. |
Once Media Gateway receives the NotificationRequest
, it will process the Signals / Events and send back NotificationRequestResponse
which carries ReturnCode
indicating if Signals can be applied or not and Events can be detected or not.
public void onNotificationRequestResponse(NotificationRequestResponse event, ActivityContextInterface aci) { logger.info("onNotificationRequestResponse"); ReturnCode status = event.getReturnCode(); switch (status.getValue()) { case ReturnCode.TRANSACTION_EXECUTED_NORMALLY: logger.info("The Announcement should have been started"); break; default: ReturnCode rc = event.getReturnCode(); logger.severe("RQNT failed. Value = " + rc.getValue() + " Comment = " + rc.getComment()); //Send DLCX to MMS. Send BYE to UA break; } }
The Media Gateway will fire the Notify
command to Application when ever it detects any of the above Events
requested by NotificationRequest
public void onNotifyRequest(Notify event, ActivityContextInterface aci) { logger.info("onNotifyRequest"); NotifyResponse response = new NotifyResponse(event.getSource(), ReturnCode.Transaction_Executed_Normally); response.setTransactionHandle(event.getTransactionHandle()); mgcpProvider.sendMgcpEvents(new JainMgcpEvent[] { response });EventName[] observedEvents = event.getObservedEvents();
for (EventName observedEvent : observedEvents) { switch (observedEvent.getEventIdentifier().intValue()) { case MgcpEvent.REPORT_ON_COMPLETION: logger.info("Announcemnet Completed NTFY received"); break; case MgcpEvent.REPORT_FAILURE: logger.info("Announcemnet Failed received"); // TODO : Send DLCX and Send BYE to UA break; case MgcpEvent.DTMF_0: logger.info("You have pressed 0"); sendRQNT(DTMF_0, false); break; case MgcpEvent.DTMF_1: logger.info("You have pressed 1"); sendRQNT(DTMF_1, false); break; case MgcpEvent.DTMF_2: logger.info("You have pressed 2"); sendRQNT(DTMF_2, false); break; case MgcpEvent.DTMF_3: logger.info("You have pressed 3"); sendRQNT(DTMF_3, false); break; case MgcpEvent.DTMF_4: logger.info("You have pressed 4"); sendRQNT(DTMF_4, false); break; case MgcpEvent.DTMF_5: logger.info("You have pressed 5"); sendRQNT(DTMF_5, false); break; case MgcpEvent.DTMF_6: logger.info("You have pressed 6"); sendRQNT(DTMF_6, false); break; case MgcpEvent.DTMF_7: logger.info("You have pressed 7"); sendRQNT(DTMF_7, false); break; case MgcpEvent.DTMF_8: logger.info("You have pressed 8"); sendRQNT(DTMF_8, false); break; case MgcpEvent.DTMF_9: logger.info("You have pressed 9"); sendRQNT(DTMF_9, false); break; case MgcpEvent.DTMF_A: logger.info("You have pressed A"); sendRQNT(A, false); break; case MgcpEvent.DTMF_B: logger.info("You have pressed B"); sendRQNT(B, false); break; case MgcpEvent.DTMF_C: logger.info("You have pressed C"); sendRQNT(C, false); break; case MgcpEvent.DTMF_D: logger.info("You have pressed D"); sendRQNT(D, false); break; case MgcpEvent.DTMF_STAR: logger.info("You have pressed *"); sendRQNT(STAR, false); break; case MgcpEvent.DTMF_HASH: logger.info("You have pressed C"); sendRQNT(POUND, false); break; } } }
Send the | |
The |
Finally when user hangs-up, we need to delete the connection on Endpoint and free the resources
public void onCallTerminated(RequestEvent evt, ActivityContextInterface aci) {EndpointIdentifier endpointID = new EndpointIdentifier(this.getEndpointName(), JBOSS_BIND_ADDRESS + ":" + MGCP_PEER_PORT); DeleteConnection deleteConnection = new DeleteConnection(this, endpointID); deleteConnection.setTransactionHandle(mgcpProvider.getUniqueTransactionHandler()); mgcpProvider.sendMgcpEvents(new JainMgcpEvent[] { deleteConnection });
ServerTransaction tx = evt.getServerTransaction(); Request request = evt.getRequest(); try { Response response = messageFactory.createResponse(Response.OK, request); tx.sendResponse(response); } catch (Exception e) { logger.severe("Error while sending DLCX ", e); } }
The SIP11 RA fires BYE event, slee container calls onCallTerminated method on SBB | |
New |
The easiest way to try the example application is to start the JAIN SLEE container, deploy the RA's as mentioned in 2.1.2. Software Prerequisites. Start the Mobicents Media Server.
Fire your favorite SIP Phone. Point the proxy of your SIP Phone to Mobicents JAIN SLEE Server and dial
To test IVR functionality
To test Recording functionality
To test Conference functionality
To test TTS functionality
Revision History | |||
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Revision 1.0 | Tue Dec 30 2009 | ||
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