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How to implement OSPF routing in OMNeT++

To Implement Open Shortest Path First (OSPF) routing in OMNeT++ has contains to setup a network that the routers will transmit the link-state information to estimate the shortest path to each destination and the OSPF is a widely used link-state routing protocol that works over the single autonomous system (AS).

The below are the procedure to implement the OSPF routing in OMNeT++ using the INET framework.

Step-by-Step Implementation:

Step 1: Set Up OMNeT++ and INET Framework

  1. Install OMNeT++:
    • Make sure OMNeT++ is installed on system. We need to download it from the OMNeT++
  2. Install the INET Framework:
    • Download and install the INET Framework, which offers numerous networking protocols and models that concludes OSPF. INET can be downloaded from the INET GitHub repository.

Step 2: Create a New OMNeT++ Project

  1. Create the Project:
    • Open OMNeT++ and generate a new OMNeT++ project through File > New > OMNeT++ Project.
    • Name project like OSPFSimulation 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: Define the Network Topology

  1. Create a NED File:
    • Describe network topology using the NED language. This topology will embrace routers and hosts that will use OSPF routing.

Example:

network OSPFNetwork

{

submodules:

router1: Router {

@display(“p=100,200”);

}

router2: Router {

@display(“p=300,200”);

}

router3: Router {

@display(“p=200,300”);

}

host1: StandardHost {

@display(“p=50,350”);

}

host2: StandardHost {

@display(“p=350,350”);

}

connections allowunconnected:

router1.ethg++ <–> Eth10Mbps <–> router2.ethg++;

router2.ethg++ <–> Eth10Mbps <–> router3.ethg++;

router3.ethg++ <–> Eth10Mbps <–> router1.ethg++;

router1.ethg++ <–> Eth10Mbps <–> host1.ethg++;

router3.ethg++ <–> Eth10Mbps <–> host2.ethg++;

}

  1. Configure Network Parameters:
    • Set up necessary link of performance metrics like bandwidth, delay, and packet loss to mimic a realistic network environment.

Step 4: Configure OSPF Routing in INET

  1. Use INET’s Built-in OSPF Support:
    • INET already concludes to support for OSPF routing, so we don’t need to execute the OSPF protocol from scratch. Instead of we will configure OSPF in the network.
  2. Configure OSPF in the NED File:
    • Each router must be configured to execute the OSPF. We do this by specifying the OSPF configuration in the NED file or in the omnetpp.ini configuration file.

Example (NED configuration for OSPF):

router1: Router {

@display(“p=100,200”);

ipv4.routingTable.ospfConfig = default;

}

  1. Configure OSPF in omnetpp.ini:
    • We need to specify OSPF parameters like area ID, interface cost, and others in the omnetpp.ini file.

Example:

network = OSPFNetwork

sim-time-limit = 100s

**.ipv4.ospf.areaId = “0.0.0.0”

**.ipv4.ospf.routerId = “1.1.1.1”

**.ipv4.ospf.interfaces[*].interfaceCost = 10

**.router1.ipv4.ospf.areaId = “0.0.0.0”

**.router2.ipv4.ospf.areaId = “0.0.0.0”

**.router3.ipv4.ospf.areaId = “0.0.0.0”

**.router1.ipv4.ospf.routerId = “1.1.1.1”

**.router2.ipv4.ospf.routerId = “2.2.2.2”

**.router3.ipv4.ospf.routerId = “3.3.3.3”

**.host1.numApps = 1

**.host1.app[0].typename = “UdpBasicApp”

**.host1.app[0].destAddress = “host2”

**.host1.app[0].destPort = 5000

**.host1.app[0].messageLength = 1024B

**.host1.app[0].sendInterval = uniform(1s, 2s)

**.host2.numApps = 1

**.host2.app[0].typename = “UdpBasicApp”

**.host2.app[0].destAddress = “host1”

**.host2.app[0].destPort = 5000

**.host2.app[0].messageLength = 1024B

**.host2.app[0].sendInterval = uniform(1s, 2s)

Step 5: Set Up the Simulation

  1. Configure the Simulation in omnetpp.ini:
    • Set up the simulation parameters like simulation time, network settings, and traffic patterns as shown in the example above.
  2. Traffic Configuration:
    • Configure the traffic patterns like UDP applications running on the hosts, to make network activity and trigger OSPF routing updates.

Step 6: Run the Simulation

  1. Compile the Project:
    • Make certain everything is correctly executed and compiled.
  2. Run Simulations:
    • Implement the simulations using OMNeT++’s IDE or command line. Monitor how the OSPF routing protocol converges and routes packets.

Step 7: Analyse the Results

  1. Monitor OSPF Behaviour:
    • To measure how OSPF routers exchange link-state advertisements (LSAs), build the link-state database (LSDB), and compute the shortest path using Dijkstra’s algorithm.
  2. Evaluate Performance:
    • To measure the key performance metrics like convergence time, packet delivery ratio, and network stability.
    • Scalars and Vectors: Use OMNeT++ tools to record and measure scalar and vector data, like the number of LSAs sent, the convergence time, and packet delivery statistics.
  3. Check for Issues:
    • Look for difficulties that have routing loops, slow convergence, or excessive delay that may designate issues with the OSPF configuration.

Step 8: Refine and Optimize the Simulation

  1. Address Any Issues:
    • Regulate OSPF parameters or network configuration based on the simulation results to enhance the performance.
  2. Re-Test:
    • Run the simulation again with the optimized configuration to verify the enhancements.

We demonstrate how the OSPF routing will execute that has make the network then exchange the information in link state and then it estimated the shortest path in the network. We also offer how the OSPF will perform in other simulation tool. Regarding link-state routing protocols, we are dedicated to assisting you with your projects. Please stay connected with omnet-manual.com for simulation and configuration outcomes related to OSPF routing within the OMNeT++ tool for your initiatives. We also provide you with the latest project ideas, accompanied by comparative analysis support in this domain.

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