To simulate Session Initiation Protocol (SIP) project using OMNeT++, we can simulate SIP-based communication by generating a custom SIP implementation and constructing a network with SIP user agents, SIP proxies, and media servers. It is a signalling protocol utilized for initiating, handling, and terminating real-time communication sessions, that contain voice, video calls, and messaging over IP networks. The SIP signalling messages are usually interchanged among these components to introduce and handle the communication sessions.
Here’s a step-by-step guide on how to simulate Session Initiation Protocol (SIP) projects in OMNeT++ using custom implementations:
Steps to Simulate Session Initiation Protocol Projects in OMNeT++
Step 1: Install OMNeT++ and INET Framework
Make sure that OMNeT++ and the INET framework are installed. INET deliver modules like hosts, routers, and communication channels that will perform as the foundation for SIP network.
- Download OMNeT++: OMNeT++
- Download INET Framework: INET Framework
Step 2: Define the Network Topology in the NED File
We will describe a network that contains of SIP clients (User Agents), SIP proxy servers, and media servers to handle the signalling and the media sessions. SIP clients will begins calls, and the proxy will route and handle the sessions.
Here’s an sample NED file that describes a simple SIP network:
network SIPNetwork
{
submodules:
userAgent1: StandardHost {
@display(“p=100,200”);
}
userAgent2: StandardHost {
@display(“p=500,200”);
}
proxyServer: StandardHost {
@display(“p=300,300”);
}
connections:
userAgent1.ethg++ <–> Eth100M <–> proxyServer.ethg++;
userAgent2.ethg++ <–> Eth100M <–> proxyServer.ethg++;
}
- userAgent1 and userAgent2 signify SIP clients that will initiate and receive SIP calls.
- proxyServer perform a SIP proxy that routes the SIP messages among user agents.
Step 3: Implement SIP Protocol in C++
We required to execute the SIP protocol logic, that contain the standard SIP messages like INVITE, TRYING, RINGING, ACK, and BYE for begins and ending the sessions.
Step 3.1: SIP User Agent Class
The SIP User Agent will manage initiating and responding to SIP calls. It transmit INVITE messages to introdce a session and processes incoming SIP responses.
Here’s an instance of a basic SIP User Agent implementation in C++:
class SIPUserAgent : public cSimpleModule
{
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void sendInvite();
void processResponse(cMessage *msg);
void sendAck();
void sendBye();
};
Define_Module(SIPUserAgent);
void SIPUserAgent::initialize()
{
// Simulate sending an INVITE message at the start of the simulation
if (strcmp(getName(), “userAgent1”) == 0) {
sendInvite();
}
}
void SIPUserAgent::handleMessage(cMessage *msg)
{
processResponse(msg);
}
void SIPUserAgent::sendInvite()
{
// Send an INVITE request to the SIP proxy server
EV << “Sending INVITE from userAgent1\n”;
cMessage *invite = new cMessage(“INVITE”);
send(invite, “ethg$o”);
}
void SIPUserAgent::processResponse(cMessage *msg)
{
if (strcmp(msg->getName(), “100 TRYING”) == 0) {
EV << “Received TRYING response\n”;
} else if (strcmp(msg->getName(), “180 RINGING”) == 0) {
EV << “Received RINGING response\n”;
} else if (strcmp(msg->getName(), “200 OK”) == 0) {
EV << “Received OK, sending ACK\n”;
sendAck();
} else if (strcmp(msg->getName(), “BYE”) == 0) {
EV << “Received BYE, terminating call\n”;
sendBye();
}
delete msg;
}
void SIPUserAgent::sendAck()
{
// Send ACK to confirm the session setup
cMessage *ack = new cMessage(“ACK”);
send(ack, “ethg$o”);
}
void SIPUserAgent::sendBye()
{
// Send BYE to terminate the session
cMessage *bye = new cMessage(“BYE”);
send(bye, “ethg$o”);
}
- userAgent1 initiates a session by sending an INVITE.
- It processes responses such as TRYING, RINGING, and 200 OK and transmits an ACK to introduce the session.
Step 3.2: SIP Proxy Server Class
The SIP Proxy Server routes SIP messages among user agents and processes incoming requests. It forwards INVITE messages, responds with 100 TRYING and 180 RINGING, and permits the 200 OK to the caller.
Here’s an instance of a SIP Proxy Server implementation:
class SIPProxyServer : public cSimpleModule
{
protected:
virtual void handleMessage(cMessage *msg) override;
void processInvite(cMessage *msg);
};
Define_Module(SIPProxyServer);
void SIPProxyServer::handleMessage(cMessage *msg)
{
if (strcmp(msg->getName(), “INVITE”) == 0) {
processInvite(msg);
}
delete msg;
}
void SIPProxyServer::processInvite(cMessage *msg)
{
EV << “Proxy received INVITE, sending TRYING and RINGING responses\n”;
// Send TRYING response
cMessage *trying = new cMessage(“100 TRYING”);
send(trying, “ethg$o”, 0); // Send to userAgent1
// Simulate forwarding INVITE to userAgent2 and getting a response
cMessage *ringing = new cMessage(“180 RINGING”);
send(ringing, “ethg$o”, 1); // Send to userAgent2
}
The proxy server receives an INVITE from the caller, transmits a TRYING response, and then forwards the RINGING response to the user agents.
Step 4: Configure the Simulation in omnetpp.ini
In the omnetpp.ini file, setting up the network settings, that contain IP addresses and link parameters such as data rate and delay.
[Config SIPNetworkSimulation]
network = SIPNetwork
sim-time-limit = 100s
# Assign IP addresses to the user agents and proxy server
*.userAgent1.ipv4.config = “manual”
*.userAgent1.ipv4.addresses = “10.0.0.1/24”
*.userAgent2.ipv4.config = “manual”
*.userAgent2.ipv4.addresses = “10.0.0.2/24”
*.proxyServer.ipv4.config = “manual”
*.proxyServer.ipv4.addresses = “10.0.0.254/24”
# Set up link parameters (e.g., data rate, delay)
*.userAgent1.eth[0].datarate = 100Mbps
*.userAgent2.eth[0].datarate = 100Mbps
*.proxyServer.eth[0].datarate = 100Mbps
This configuration sets up the SIP clients and the SIP proxy server with static IP addresses and communication parameters.
Step 5: Simulate the SIP Session
Once the network is configured and the protocol logic is executed:
- Build and compile the project in OMNeT++.
- Run the simulation in the OMNeT++ GUI or from the command line.
- Observe SIP message exchanges: We will see the SIP messages (e.g., INVITE, TRYING, RINGING, OK, ACK) being interchanged among the user agents and the proxy server.
Step 6: Analyse the Simulation Results
OMNeT++ creates .sca and .vec files encompassing detailed simulation data like the time it took to introduce the session, the messages interchanged, and network performance parameters.
We can measure key SIP parameters such as:
- Call setup delay: The time flanked by the INVITE message and the session being introduced (ACK received).
- Call duration: The total time among the session establishment and termination (BYE received).
- Message throughput: The rate at which SIP messages are transmitting and run by the clients and server.
Step 7: Extend the SIP Simulation
Once we have the simple SIP protocol working, we can prolong the simulation by adding additional behaviors:
7.1: Introduce Media Streams
SIP is utilized to configure the session, however media streams such as audio or video are usually transported using RTP (Real-Time Transport Protocol). We can replicate RTP streams after the SIP session is introduced.
void SIPUserAgent::sendRtpStream()
{
// Simulate sending media stream after session is established
cMessage *media = new cMessage(“RTP Media”);
send(media, “ethg$o”);
}
7.2: Handle SIP Registration
Expand the protocol to contain REGISTER messages, in which clients register with the proxy server before starts or receiving calls.
7.3: Simulate Multiple SIP Clients and Proxy Servers
Extend the network to contain multiple SIP clients and proxy servers, and replicate call routing through diverse domains.
7.4: Introduce Call Failures and Retries
Replicate network failures or busy signals and apply logic for clients to manage failed calls or retry after a timeout.
if (networkFailure) {
EV << “Network failure, retrying after timeout\n”;
scheduleAt(simTime() + 5, retryCall); // Retry call after 5 seconds
}
Example of Multiple SIP Proxies in the NED File:
network SIPMultiProxyNetwork
{
submodules:
userAgent1: StandardHost;
userAgent2: StandardHost;
proxyServer1: StandardHost;
proxyServer2: StandardHost;
connections:
userAgent1.ethg++ <–> Eth100M <–> proxyServer1.ethg++;
proxyServer1.ethg++ <–> Eth100M <–> proxyServer2.ethg++;
proxyServer2.ethg++ <–> Eth100M <–> userAgent2.ethg++;
}
If you need more details on specific SIP features, like handling multiple sessions, handling media streams with RTP, or adding SIP authentication, feel free to ask for further guidance!
Finally, we had successfully delivered the significant procedures to simulate the Session Initiation Protocol in OMNeT++ tool and also we deliver the sample snippets and their explanation. More information will be shared about this process in upcoming manual.
Get in touch with us for expert guidance on the protocols involved in initiating, managing, and concluding real-time communication sessions. Our developers are available to conduct a thorough network evaluation for your projects. For simulating Session Initiation Protocol projects using the OMNeT++ tool, we offer top-tier tools and resources to ensure your work is completed efficiently and on schedule. Please share your research needs with us at phdprime.com, and we will provide you with timely assistance.
