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How to Implement Session Initiation Protocol in OMNeT++

To Implement the Session Initiation Protocol (SIP) in OMNeT++ has contains to generate the simulation design where the SIP clients that is User Agents should start, manage, and end the multimedia sessions like voice calls, video calls, or messaging with SIP servers (Proxy Server, Registrar, etc.) and the SIP operates works over both TCP and UDP and is vital for managing VoIP (Voice over IP) communications. The given below steps were help you to achieve the process:

Step-by-Step Implementation:

Step 1: Set Up the OMNeT++ Environment

  1. Install OMNeT++:
    • Make sure OMNeT++ is installed on system. We need to download it from the official OMNeT++
  2. Install the INET Framework:
    • Download and install the INET Framework, which delivers the necessary network protocol models such as TCP/UDP/IP and RTP (Real-time Transport Protocol) that SIP relies on.
    • You can get INET from its GitHub repository.

Step 2: Create a New OMNeT++ Project

  1. Create the Project:
    • Open OMNeT++ and create a new OMNeT++ project through File > New > OMNeT++ Project.
    • Name project like SIP_Simulation and set up the project directory.
  2. Set Up Project Dependencies:
    • Make sure project references the INET Framework by right-clicking on project in the Project Explorer, navigating to Properties > Project References, and checking the INET project.

Step 3: Understand SIP Basics

Before implementing SIP, it’s important to familiarize the core components of SIP:

  • User Agents (UA): These are the end devices (e.g., phones, computers) that initiate and terminate sessions.
  • SIP Proxy Server: It forwards requests from clients to the intended recipients.
  • Registrar Server: It registers the location of User Agents.
  • SIP Messages: Common SIP messages has involves INVITE, ACK, BYE, REGISTER, and OPTIONS.
  • SIP Responses: Standard responses contain 100 (Trying), 180 (Ringing), 200 (OK), etc.

Step 4: Define the Network Topology in OMNeT++

  1. Create a NED File:
    • Outline the network topology using the NED language. This topology should contain SIP clients (User Agents), SIP servers (Proxy, Registrar), and possibly other network infrastructure like routers.

Example:

network SIPNetwork

{

submodules:

client1: StandardHost;

client2: StandardHost;

proxyServer: StandardHost;

registrarServer: StandardHost;

router: Router;

connections:

client1.ethg++ <–> Eth10Mbps <–> router.ethg++;

client2.ethg++ <–> Eth10Mbps <–> router.ethg++;

proxyServer.ethg++ <–> Eth10Mbps <–> router.ethg++;

registrarServer.ethg++ <–> Eth10Mbps <–> router.ethg++;

}

  1. Configure Network Parameters:
    • Set up link parameters like bandwidth, delay, and packet loss to mimic realistic network conditions.

Step 5: Implement SIP Protocol

  1. Define SIP Modules:
    • Generate NED modules for the SIP User Agents (clients) and SIP servers (Proxy, Registrar). These modules will manage SIP operations such as session initiation, registration, and termination.

Example (in NED):

simple SIPUserAgent

{

parameters:

@display(“i=block/cogwheel”);

gates:

inout udpIn;

inout udpOut;

}

simple SIPProxyServer

{

parameters:

@display(“i=block/server”);

gates:

inout udpIn;

inout udpOut;

}

simple SIPRegistrarServer

{

parameters:

@display(“i=block/server”);

gates:

inout udpIn;

inout udpOut;

}

  1. Implement SIP Logic in C++:
    • SIP User Agent Implementation:
      • Write the C++ code for the SIP User Agent. The agent should create a UDP connection with the SIP server, send SIP requests (e.g., INVITE), and handle server responses.

Example (in C++):

void SIPUserAgent::handleMessage(cMessage *msg) {

if (msg->isSelfMessage()) {

initiateSession();

} else if (msg->arrivedOn(“udpIn”)) {

handleServerResponse(msg);

}

}

void SIPUserAgent::initiateSession() {

// Create an INVITE message

SIPMessage *invite = new SIPMessage(“INVITE”);

invite->setCommand(“INVITE”);

invite->setUri(“sip:client2@domain.com”);

// Send the message to the proxy server

send(invite, “udpOut”);

}

void SIPUserAgent::handleServerResponse(cMessage *msg) {

SIPMessage *sipMessage = check_and_cast<SIPMessage *>(msg);

if (sipMessage->getCommand() == “200 OK”) {

// Handle session setup

} else if (sipMessage->getCommand() == “BYE”) {

// Handle session termination

sendResponse(“200 OK”);

}

}

void SIPUserAgent::sendResponse(const std::string &responseCode) {

SIPMessage *response = new SIPMessage(responseCode);

send(response, “udpOut”);

}

    • SIP Proxy Server Implementation:
      • Implement the SIP Proxy Server to forward SIP requests from clients to their intended recipients.

Example (in C++):

void SIPProxyServer::handleMessage(cMessage *msg) {

if (msg->arrivedOn(“udpIn”)) {

handleClientRequest(msg);

}

}

void SIPProxyServer::handleClientRequest(cMessage *msg) {

SIPMessage *sipMessage = check_and_cast<SIPMessage *>(msg);

if (sipMessage->getCommand() == “INVITE”) {

// Forward INVITE to the recipient

send(sipMessage, “udpOut”);

} else if (sipMessage->getCommand() == “REGISTER”) {

// Handle registration with the registrar

send(sipMessage, “udpOut”);

}

}

    • SIP Registrar Server Implementation:
      • Implement the SIP Registrar Server to manage REGISTER requests and preserve the location database of User Agents.

Example (in C++):

void SIPRegistrarServer::handleMessage(cMessage *msg) {

if (msg->arrivedOn(“udpIn”)) {

handleRegisterRequest(msg);

}

}

void SIPRegistrarServer::handleRegisterRequest(cMessage *msg) {

SIPMessage *sipMessage = check_and_cast<SIPMessage *>(msg);

if (sipMessage->getCommand() == “REGISTER”) {

// Register the user’s location

// Respond with 200 OK

SIPMessage *response = new SIPMessage(“200 OK”);

send(response, “udpOut”);

}

}

  1. Create SIP Message Types:
    • Describe custom message types for SIP messages like INVITE, ACK, BYE, REGISTER, and their corresponding responses.

Example (in C++):

class SIPMessage : public cMessage {

public:

std::string command;

std::string uri;

…

};

Step 6: Configure the Simulation

  1. Set Up the UDP Stack:
    • In the omnetpp.ini file, configure the SIP clients and servers to use the UDP stack provided by the INET Framework.

Example:

network = SIPNetwork

*.client1.numUdpApps = 1

*.client1.udpApp[0].typename = “UDPBasicApp”

*.client1.udpApp[0].destPort = 5060  // Port 5060 for SIP

*.client1.udpApp[0].destAddress = “proxyServer”

*.client2.numUdpApps = 1

*.client2.udpApp[0].typename = “UDPBasicApp”

*.client2.udpApp[0].destPort = 5060

*.client2.udpApp[0].destAddress = “proxyServer”

*.proxyServer.numUdpApps = 1

*.proxyServer.udpApp[0].typename = “UDPBasicApp”

*.proxyServer.udpApp[0].localPort = 5060

*.registrarServer.numUdpApps = 1

*.registrarServer.udpApp[0].typename = “UDPBasicApp”

*.registrarServer.udpApp[0].localPort = 5060

  1. Define SIP Scenarios:
    • Specify the SIP scenarios to simulate, such as call setup, call hold, and call teardown.

Step 7: Simulate and Test SIP

  1. Compile the Project:
    • Build OMNeT++ project to make sure everything is executed correctly.
  2. Run the Simulation:
    • Execute the simulation and monitor how SIP clients and servers interact. Validate that clients can start and end sessions correctly.
  3. Analyze Results:
    • Use OMNeT++ tools to observe SIP message exchanges, response times, and overall protocol performance. Make sure that the SIP implementation works properly under numerous network conditions.

Step 8: Refine and Extend

  1. Enhance SIP Functionality:
    • Add more advanced characteristics to SIP implementation, like handling SIP OPTIONS requests, supporting SIP over TCP, or implementing SIP forking.
  2. Test with Different Network Configurations:
    • To emulate the numerous network conditions like high latency, packet loss to test the robustness of SIP implementation.
  3. Performance Optimization:
    • Enhance the execution to manage multiple concurrent SIP sessions efficiently and ensure scalability.

As we deliberated earlier about how the Session Initiation Protocol will achieve in OMNeT++ tool and we aid to afford more information about how the Session Initiation Protocol will adapt in diverse settings. Discover how session initiation protocol clients facilitate server connections and disconnections over TCP and UDP, with implementations and simulation support from our experts guidance shared on  OMNeT++tool.