To simulate Unicast Routing in OMNeT++ has includes to set up configure a network in which packets are transmit from a single source to a single destination. In unicast routing, each packet is forwarded according to the routing table of each router along the path. The routing tables can be set up whether statically or dynamically, liable on whether we are using static or dynamic routing protocols such as OSPF, RIP, or custom routing.
Here’s a detailed guide to simulating Unicast Routing projects using OMNeT++:
Steps to Simulate Unicast Routing Projects in OMNeT++
Step 1: Install OMNeT++ and INET Framework
Make sure that OMNeT++ and the INET framework are installed. INET supports built-in support for numeous unicast routing protocols such as OSPF, RIP, or manual static routing.
- Download OMNeT++: OMNeT++
- Download INET Framework: INET Framework
Step 2: Define the Network Topology in the NED File
Generate a network topology with routers and hosts that can interact through unicast routing. The .ned file defines the structure of the network.
Here’s an instance NED file that describes a simple network in which unicast routing is applied:
network UnicastRoutingNetwork
{
submodules:
host1: StandardHost {
@display(“p=100,200”);
}
host2: StandardHost {
@display(“p=500,200”);
}
router1: Router {
@display(“p=200,300”);
}
router2: Router {
@display(“p=300,300”);
}
router3: Router {
@display(“p=400,300”);
}
connections:
host1.ethg++ <–> Eth100M <–> router1.ethg++;
router1.ethg++ <–> Eth100M <–> router2.ethg++;
router2.ethg++ <–> Eth100M <–> router3.ethg++;
router3.ethg++ <–> Eth100M <–> host2.ethg++;
}
In this topology:
- host1 and host2 are the source and destination of unicast traffic.
- router1, router2, and router3 route packets among the two hosts using unicast routing.
Step 3: Configure Routing in OMNeT++ via the INET Framework
Unicast routing can be executed using either Static Routing or Dynamic Routing protocols such as OSPF or RIP.
Option 1: Static Routing Configuration
In static routing, the routing tables of each router are physically set up to describe the next hop for each destination.
Step 3.1: Assign IP Addresses
In the omnetpp.ini file, manually allocate IP addresses to each host and router in the network.
[Config StaticRoutingNetworkSimulation]
network = UnicastRoutingNetwork
sim-time-limit = 100s
# Assign IP addresses to hosts and routers
*.host1.ipv4.config = “manual”
*.host1.ipv4.addresses = “10.0.0.1/24”
*.host2.ipv4.config = “manual”
*.host2.ipv4.addresses = “10.0.3.1/24”
*.router1.ipv4.config = “manual”
*.router1.ipv4.addresses = “10.0.0.254/24 10.0.1.1/24”
*.router2.ipv4.config = “manual”
*.router2.ipv4.addresses = “10.0.1.254/24 10.0.2.1/24”
*.router3.ipv4.config = “manual”
*.router3.ipv4.addresses = “10.0.2.254/24 10.0.3.254/24”
Step 3.2: Configure Static Routing Tables
Set up the static routing tables for each router in an XML file and link the XML file in the omnetpp.ini configuration. For each router, we define how packets should be forwarded in terms of the destination IP.
Here’s an instance of a routing file (router1_routing.xml) for router1:
<config>
<route>
<destination>10.0.3.0</destination> <!– Destination is host2 subnet –>
<gateway>10.0.1.254</gateway> <!– Forward to router2 –>
<interface>eth1</interface>
<netmask>255.255.255.0</netmask>
</route>
</config>
In the omnetpp.ini file, you link the routing files for each router:
# Static routing table for each router
*.router1.routingTable.routingFile = xmldoc(“router1_routing.xml”)
*.router2.routingTable.routingFile = xmldoc(“router2_routing.xml”)
*.router3.routingTable.routingFile = xmldoc(“router3_routing.xml”)
Each router requires its own routing table, requiring how to reach the destination subnets.
Option 2: Dynamic Routing with OSPF (Link-State Routing)
In dynamic routing, we can utilize a protocol such as OSPF (Open Shortest Path First), that estimate the shortest path dynamically in terms of link-state information.
Step 3.1: Assign IP Addresses
Utilize the same IP addressing scheme as in static routing:
[Config OSPFRoutingNetworkSimulation]
network = UnicastRoutingNetwork
sim-time-limit = 100s
# Assign IP addresses to hosts and routers
*.host1.ipv4.config = “manual”
*.host1.ipv4.addresses = “10.0.0.1/24”
*.host2.ipv4.config = “manual”
*.host2.ipv4.addresses = “10.0.3.1/24”
*.router1.ipv4.config = “manual”
*.router1.ipv4.addresses = “10.0.0.254/24 10.0.1.1/24”
*.router2.ipv4.config = “manual”
*.router2.ipv4.addresses = “10.0.1.254/24 10.0.2.1/24”
*.router3.ipv4.config = “manual”
*.router3.ipv4.addresses = “10.0.2.254/24 10.0.3.254/24”
Step 3.2: Enable OSPF for Dynamic Unicast Routing
Permit OSPF on each router to dynamically estimate the shortest paths using Dijkstra’s techniques.
# Enable OSPF on the routers
*.router1.hasOspf = true
*.router1.routingTable.ospfRouterID = “1.1.1.1”
*.router1.routingTable.ospfAreaID = “0.0.0.0”
*.router2.hasOspf = true
*.router2.routingTable.ospfRouterID = “2.2.2.2”
*.router2.routingTable.ospfAreaID = “0.0.0.0”
*.router3.hasOspf = true
*.router3.routingTable.ospfRouterID = “3.3.3.3”
*.router3.routingTable.ospfAreaID = “0.0.0.0”
This set up permit OSPF on each router, and the routers will enthusiastically estimate the best path among hosts.
Step 4: Simulate Unicast Traffic Between Hosts
To validate the unicast routing functionality, replicate UDP traffic among host1 and host2.
# Simulate UDP traffic from host1 to host2
*.host1.numApps = 1
*.host1.app[0].typename = “UdpBasicApp”
*.host1.app[0].localAddress = “10.0.0.1”
*.host1.app[0].connectAddress = “10.0.3.1”
*.host1.app[0].sendInterval = 1s
*.host1.app[0].messageLength = 512B
*.host1.app[0].startTime = 10s
# Configure host2 to receive UDP traffic
*.host2.numApps = 1
*.host2.app[0].typename = “UdpSinkApp”
In this setup:
- host1 creates UDP traffic and transmit it to host2 at regular intervals.
- host2 receives the traffic.
Step 5: Run the Simulation
Once the network topology and routing (static or dynamic) are configured:
- Build and compile the project in OMNeT++.
- Run the simulation using the OMNeT++ GUI or from the command line.
- Observe the routing behavior: Utilize the OMNeT++ GUI to envision packet flow, routing table updates, and dynamic route calculations (if using OSPF).
Step 6: Analyse Simulation Results
OMNeT++ creates .sca and .vec files containing simulation outcomes. We can measure numerous key metrics related to unicast routing:
- Packet Delivery Ratio: Assess how many packets are successfully delivered among hosts.
- End-to-End Delay: measure on how long it takes for packets to travel from source to destination.
- Routing Table Updates: If using dynamic routing, monitor how routing tables are updated enthusiastically.
- Network Convergence Time: For dynamic routing, evaluate how long it takes the network to converge to a stable state after changes.
Utilize OMNeT++’s built-in analysis tools to envision these parameters and evaluate the performance of unicast routing.
Step 7: Experiment with Different Scenarios
We can prolong the simulation by validate numerous configurations and environment:
7.1: Simulate Link Failures
Establish link failures in the network and monitor how the routers adapt (dynamic routing) or how packets are dropped (static routing).
# Simulate a link failure between router1 and router2 at 50 seconds
*.router1.interfaceTable[1].downAt = 50s
7.2: Measure Traffic Load
Replicate higher traffic load by increasing the transmit rate and monitor how the network manage congestion.
# Increase traffic load to simulate congestion
*.host1.app[0].sendInterval = 0.1s # Increase message rate
7.3: Experiment with Larger Networks
Extend the network by adding more routers and hosts to replicate larger unicast networks and measure routing performance on a larger scale.
network LargerUnicastRoutingNetwork
{
submodules:
host1: StandardHost;
host2: StandardHost;
router1: Router;
router2: Router;
router3: Router;
router4: Router; // Add more routers
connections:
host1.ethg++ <–> Eth100M <–> router1.ethg++;
router1.ethg++ <–> Eth100M <–> router2.ethg++;
router2.ethg++ <–> Eth100M <–> router3.ethg++;
router3.ethg++ <–> Eth100M <–> router4.ethg++;
router4.ethg++ <–> Eth100M <–> host2.ethg++;
}
Step 8: Visualize the Routing Process
Make utilize OMNeT++’s built-in envision tools to animate the packet flow and monitor how routing tables are updated dynamically (in the case of OSPF).
Summary of Steps:
- Install OMNeT++ and INET Framework.
- Define Network Topology: Generate a network with hosts and routers using a NED file.
- Configure Routing: select among static or dynamic routing (OSPF or RIP).
- Simulate Unicast Traffic: create UDP traffic among hosts to validate routing functionality.
- Run the Simulation: monitor the routing behaviour and envision packet flow.
- Analyse Results: measure routing parameters such as delivery ratio and end-to-end delay.
- Experiment with Different Scenarios: validate with link failures, larger networks, or higher traffic loads.
- Visualize Routing: monitor the routing decisions in real-time using OMNeT++ visualization tools.
In this setup we had clearly gather information on how to setup the simulation and how to replicate the Unicast Routing using OMNeT++ tool. We will offer insights into the implementation of the Unicast Routing in diverse simulation scenarios. If you want the best results for Unicast Routing Projects using the OMNeT++ tool, you can count on our experts for reliable simulation support. We also handle both static and dynamic routing protocols, depending on what your project requires.
