To simulate Session Layer projects using OMNeT++ can be difficult task, as OMNeT++ and INET usually concentrate on lower layers of the OSI model, especially the physical, data link, network, and transport layers. But, we can replicate some of the functionalities usually linked with the session layer by executes the characteristics such as session management, connection control, and maintaining stateful communications.
The Session Layer (Layer 5 in the OSI model) handles the sessions among two communicating parties that includes to introducing, maintaining, and terminating communication sessions, and make sure that data streams are appropriately synchronized. In the aspects of OMNeT++, we can simulate session layer functionalities by prolonging transport-layer protocols (e.g., TCP) and building session management on top of that.
Here’s a step-by-step guide to simulating Session Layer projects using OMNeT++:
Steps to Simulate Session Layer Projects in OMNeT++
- Install OMNeT++ and INET Framework
- Download and install OMNeT++ from here.
- Download and install the INET framework from INET GitHub repository. INET offered the support for TCP, UDP, and other transport protocols that can be extended to handle session layer behavior.
- Understand the Key Session Layer Functionalities
The session layer usually handles:
- Session establishment: configure a connection among two endpoints.
- Session maintenance: handling the on-going data exchange and keeping monitor of session state.
- Session termination: Properly closing or releasing a session when it’s no longer essential.
- Synchronization: Managing checkpoints or recovery mechanisms in case of failure.
- Define the Network Topology (NED File)
Generate a simple network with two hosts communicating over TCP or UDP. The session layer logic will be executed on top of these transport protocols.
Example NED files for the Network:
network SessionLayerNetwork {
submodules:
client: StandardHost {
@display(“p=100,200”);
}
server: StandardHost {
@display(“p=300,200”);
}
connections allowunconnected:
client.ethg++ <–> Eth100M <–> server.ethg++;
}
This NED file configures a simple network with a client and a server associated through Ethernet.
- Extend the Transport Layer to Simulate the Session Layer
While OMNeT++ doesn’t have a direct implementation of the session layer, we can emulate session management by prolonging the functionality of the transport layer protocols like TCP or UDP.
We can compose to a custom application that executes on top of TCP or UDP and handles session states (e.g., open, active, closed).
Steps for Session Management:
- Session establishment: Utilize a TCP connection establishment process to replicate session initiation (e.g., TCP handshake).
- Session management: Keep monitor of the session state (open, active, suspended, or closed) and handle session-related logic such as timeouts or retries.
- Session termination: Close the session once the data interchange is complete or after a timeout.
- Create a Custom Session Layer Application
We can generate a new class that replicate session layer behaviour, like handling the session’s lifecycle and keeping track of session states.
Example: SessionLayerApp.cc
#include “inet/applications/tcpapp/TcpAppBase.h”
class SessionLayerApp : public inet::TcpAppBase {
private:
int sessionState; // 0 = closed, 1 = open, 2 = active
protected:
virtual void initialize(int stage) override;
virtual void handleTimer(cMessage *msg) override;
virtual void socketEstablished(int connId, void *yourPtr) override;
virtual void socketDataArrived(int connId, void *yourPtr, cPacket *msg, bool urgent) override;
virtual void socketClosed(int connId, void *yourPtr) override;
public:
SessionLayerApp();
virtual ~SessionLayerApp();
};
// Constructor
SessionLayerApp::SessionLayerApp() : sessionState(0) {}
// Destructor
SessionLayerApp::~SessionLayerApp() {}
void SessionLayerApp::initialize(int stage) {
TcpAppBase::initialize(stage);
if (stage == inet::INITSTAGE_APPLICATION_LAYER) {
// Schedule a session start event
scheduleAt(simTime() + par(“startTime”).doubleValue(), new cMessage(“startSession”));
}
}
void SessionLayerApp::handleTimer(cMessage *msg) {
if (strcmp(msg->getName(), “startSession”) == 0) {
// Open a TCP connection to the server to simulate session establishment
socket.connect(L3AddressResolver().resolve(par(“connectAddress”).stringValue()), par(“connectPort”).intValue());
sessionState = 1; // Session established (open)
}
delete msg;
}
void SessionLayerApp::socketEstablished(int connId, void *yourPtr) {
sessionState = 2; // Session is active
// Send data as part of session activity
sendPacket(“Hello, session established!”);
}
void SessionLayerApp::socketDataArrived(int connId, void *yourPtr, cPacket *msg, bool urgent) {
// Process the received data during the session
EV << “Received data: ” << msg->getName() << endl;
delete msg;
}
void SessionLayerApp::socketClosed(int connId, void *yourPtr) {
sessionState = 0; // Session closed
EV << “Session closed.” << endl;
}
In this code:
- Session Establishment: A TCP connection is introduced when the application starts, that simulates the session initiation process.
- Session Management: The sessionState variable monitors the session’s state (open, active, closed).
- Session Termination: When the connection is closed, the session is completed.
- Configure the Simulation in omnetpp.ini
Set up the configuration to process custom session layer application on the client and server nodes.
Example omnetpp.ini Configuration:
network = SessionLayerNetwork
sim-time-limit = 100s
# Session layer app parameters
**.client.numApps = 1
**.client.app[0].typename = “SessionLayerApp”
**.client.app[0].connectAddress = “server”
**.client.app[0].connectPort = 80
**.client.app[0].startTime = 1s
**.server.numApps = 1
**.server.app[0].typename = “TcpServerApp”
**.server.app[0].localPort = 80
In this configuration:
- The SessionLayerApp is allocates to the client, that will introduce a TCP connection with the server and replicate session management.
- The server executes a simple TcpServerApp to manage incoming connections and respond to the client’s requests.
- Simulate Session Layer Features
- Session Timeout: Apply the session timeouts in which the session automatically closes after a period of inactivity.
- Session Recovery: Apply mechanisms for session recovery in case of a failure, in which the session can be resumed from the last known state.
- Multiple Sessions: Replicate multiple concurrent sessions among different clients and servers, and handle each session’s state independently.
- Run the Simulation
- Execute the simulation in OMNeT++ to track session initiation, data exchange, and session termination among the client and server.
- We can track session behaviour using OMNeT++’s logging tools and evaluate session state transitions.
- Analyse the Results
OMNeT++ delivers the tools for logging session states, connection establishment, data exchanges, and connection terminations. We can utilize scalar and vector recording to monitor the following parameters:
- Session Setup Time: Time taken to introduce a session (e.g., how long the TCP handshake takes).
- Session Duration: The total time a session remains active.
- Session Termination: Monitor on how and when sessions are closed, and track if proper session end takes place.
- Extend the Simulation
We can cover the project by adding characteristics like:
- Session Checkpoints: Add checkpointing to resume intermittent sessions.
- Session Management Protocol: Execute a more complex session management protocol on top of TCP or UDP.
- Session Load Balancing: Replicate a load balancer that sends session requests via multiple servers.
We demonstrated the basic process with detailed explanation for Session Layer projects simulated and evaluated the results using the tool of OMNeT++ tool and the additional details regarding this process will be added later.
Send a message to phdprime.com with your project requirements, including the base and reference papers, and we will provide you with comprehensive results. Receive expert advice on extending transport-layer protocols for your projects. Allow phdprime.com to manage your Session Layer Projects simulation, and we guarantee timely and high-quality simulation results. We customize network performance to meet your specific project needs.
