To simulate Dynamic Routing projects using OMNeT++, which has requires to contain making a network in which routers are dynamically exchange routing data and then change their routing tables depends on the changes within the network topology. Dynamic routing protocols such as OSPF (Open Shortest Path First), RIP (Routing Information Protocol), and BGP (Border Gateway Protocol) are generally utilized in such simulations.
The simulation platform OMNeT++ and the INET framework offer support for dynamic routing, permitting to replicate distinct scenarios like network failures, topology changes, and route recalculations.
Here’s a step-by-step instruction to simulating Dynamic Routing projects using OMNeT++:
Steps to Simulate Dynamic Routing Projects in OMNeT++
Step 1: Install OMNeT++ and INET Framework
Make certain that OMNeT++ and the INET framework are installed, as INET framework delivers the essential components for IP-based dynamic routing.
- Download OMNeT++: OMNeT++ official website
- Download INET Framework: INET Framework
Step 2: Define the Network Topology in the NED File
We require to describe a network of routers and hosts in a .ned file. The routers will swap dynamic routing data and then modify their routing tables rely on the selected dynamic routing protocol.
Here’s an instance NED file for a basic network in which dynamic routing will be applied:
network DynamicRoutingNetwork
{
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++;
router1.ethg++ <–> Eth100M <–> router3.ethg++; // Additional link for redundancy
}
In this topology:
- host1 and host2 denote end devices, which will communicate via the dynamic routing network.
- router1, router2, and router3 are connected in a way that enables several routes to be discovered by dynamic routing algorithms.
Step 3: Enable Dynamic Routing in the INET Framework
The INET framework supports numerous dynamic routing protocols, like OSPF and RIP. You can select one according to your requirements. For this instruction, we will be utilized OSPF (a link-state routing protocol) since it uses Dijkstra’s algorithm and changes routes dynamically depends on the network’s link state.
Step 3.1: Assign IPv4 Addresses
In the omnetpp.ini file, allocate an IP addresses to the routers and hosts in the network.
[Config DynamicRoutingSimulation]
network = DynamicRoutingNetwork
sim-time-limit = 100s
# Assign IPv4 addresses to hosts and routers
*.host1.ipv4.config = “manual”
*.host1.ipv4.addresses = “10.0.0.1/24”
*.host2.ipv4.config = “manual”
*.host2.ipv4.addresses = “10.0.1.1/24”
*.router1.ipv4.config = “manual”
*.router1.ipv4.addresses = “10.0.0.254/24 10.0.2.1/24”
*.router2.ipv4.config = “manual”
*.router2.ipv4.addresses = “10.0.2.2/24 10.0.3.1/24”
*.router3.ipv4.config = “manual”
*.router3.ipv4.addresses = “10.0.3.2/24 10.0.1.254/24”
Step 3.2: Enable OSPF on the Routers
Allow OSPF on the routers to make sure they can exchange routing data dynamically.
# Enable OSPF on all routers
*.router1.hasOspf = true
*.router1.routingTable.ospfRouterID = “1.1.1.1”
*.router1.routingTable.ospfAreaID = “0.0.0.0”
*.router1.interfaceTable[0].ospfInterfaceType = “broadcast”
*.router1.interfaceTable[1].ospfInterfaceType = “broadcast”
*.router2.hasOspf = true
*.router2.routingTable.ospfRouterID = “2.2.2.2”
*.router2.routingTable.ospfAreaID = “0.0.0.0”
*.router2.interfaceTable[0].ospfInterfaceType = “broadcast”
*.router2.interfaceTable[1].ospfInterfaceType = “broadcast”
*.router3.hasOspf = true
*.router3.routingTable.ospfRouterID = “3.3.3.3”
*.router3.routingTable.ospfAreaID = “0.0.0.0”
*.router3.interfaceTable[0].ospfInterfaceType = “broadcast”
*.router3.interfaceTable[1].ospfInterfaceType = “broadcast”
# Enable OSPF debug logging (optional)
*.router1.routingTable.ospfDebug = true
*.router2.routingTable.ospfDebug = true
*.router3.routingTable.ospfDebug = true
Step 4: Simulate Traffic Between Hosts
To experiment the dynamic routing, we can be mimicked traffic among host1 and host2. Here’s how we can generate UDP traffic among them:
# Generate 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 = “10.0.1.1”
*.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”
Step 5: Run the Simulation
When the network and routing protocol are configured:
- Build and compile the project in OMNeT++.
- Run the simulation using the OMNeT++ GUI or command line.
- Observe dynamic routing behavior: We can be utilized the OMNeT++ GUI to envision packet flow, routing table updates, and route changes.
Step 6: Simulate Network Failures
Dynamic routing protocols such as OSPF change to network failures by recalculating routes. We can be mimicked link failures to monitor how OSPF dynamically updates the routing tables.
Simulating a Link Failure
We can replicate the failure of a link among routers and then monitor how OSPF recalculates the shortest path:
# Simulate a link failure between router1 and router2 at 50 seconds
*.router1.interfaceTable[1].downAt = 50s
When the link among router1 and router2 goes down, OSPF will identify the failure and route traffic via router3 instead.
Step 7: Analyze Simulation Results
OMNeT++ makes .sca and .vec files that encompassing simulation results. We can investigate the following dynamic routing metrics:
- Convergence Time: How long it takes for the network to stabilize after a topology change.
- End-to-End Delay: Estimate the delay experienced by packets as they travel from host1 to host2.
- Packet Delivery Ratio: Ascertain the percentage of packets effectively delivered among the hosts before and after link failures.
- Routing Table Updates: Monitor how often routing tables are updated in response to network changes.
We can be utilized OMNeT++’s analysis tools to envision these metrics and know the influence of dynamic routing on network performance.
Step 8: Experiment with Different Dynamic Routing Protocols
As well as OSPF, we can be mimicked other dynamic routing protocols, like:
8.1: RIP (Routing Information Protocol)
RIP is a distance-vector protocol, which computes routes according to the hop count. To allow RIP, we can set up the routers like this:
# Enable RIP on all routers
*.router1.hasRip = true
*.router2.hasRip = true
*.router3.hasRip = true
# Enable logging for RIP (optional)
*.router1.routingTable.ripDebug = true
*.router2.routingTable.ripDebug = true
*.router3.routingTable.ripDebug = true
8.2: BGP (Border Gateway Protocol)
For mimicking inter-domain routing, we can test with BGP within INET. BGP manages routing among autonomous systems (AS) and is helpful for large-scale internet simulations.
Step 9: Introduce Advanced Scenarios
We can expand the simulation with more complex scenarios, like:
9.1: Network Congestion
Replicate network congestion by maximizing the traffic load and monitor how dynamic routing protocols change to discover less congested paths.
# Increase traffic load to simulate congestion
*.host1.app[0].sendInterval = 0.1s
9.2: Multi-Area OSPF
If the network is large then we can be replicated a multi-area OSPF configure in which distinct routers belong to distinct OSPF areas. This is helpful for learning scalability and performance in large networks.
# Configure OSPF areas for a multi-area setup
*.router1.routingTable.ospfAreaID = “0.0.0.0” # Backbone area
*.router2.routingTable.ospfAreaID = “0.0.0.1” # Area 1
*.router3.routingTable.ospfAreaID = “0.0.0.1” # Area 1
9.3: Mobile Nodes
Replicate dynamic routing in Mobile Ad-Hoc Networks (MANETs) in which nodes are move around, triggering frequent topology changes. It wants mobility modules and can be mimicked with AODV (Ad hoc On-Demand Distance Vector) or DSDV (Destination-Sequenced Distance-Vector) routing protocols.
Step 10: Visualize the Routing Process
Utilize OMNeT++’s animation aspects to envision packet routing and how dynamic routing protocols alter routes. It is especially helpful for monitoring OSPF’s route recalculation in response to link failures or congestion.
As illustrated above simple guidelines for Dynamic Routing Projects that were simulated and analysed then visualized their results with the aid of OMNeT++ tool. More informations will also be offer later, if necessary.
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