How to Simulate Flow Based Routing Projects Using OMNeT++

To simulate flow-based routing concentrates on directing network traffic (flows) according to particular flow characteristics like source-destination pairs, QoS (Quality of Service) requirements, or traffic patterns, instead of individual packet routing decisions. Flow-based routing is frequently utilized in Software Defined Networking (SDN), traffic engineering, and for enhancing network resources rely on the nature of the traffic flow.

The following is a step-by-step instruction to replicating flow-based routing projects within OMNeT++ using the INET Framework.

Steps to Simulate Flow Based Routing Projects in OMNeT++

1. Install OMNeT++ and INET Framework

1. Download OMNeT++:
   • Install OMNeT++ from the OMNeT++ website.
2. Install INET Framework:
   • The INET Framework offers support for simple routing protocols as well as custom routing models.
   • Clone the INET repository:

git clone https://github.com/inet-framework/inet.git

1. • Import INET into OMNeT++ through File > Import > Existing Projects into Workspace, and choose the inet directory.
   • Build the project by right-clicking on the inet project and choosing Build Project.

2. Define a Network Topology in NED

Initially, describe a simple network topology, which will support flow-based routing. The network will have hosts and routers that make and forward flows.

Example NED File for Flow-Based Routing Network (FlowBasedRoutingNetwork.ned):

package flowbasedrouting;

import inet.node.inet.Router;

import inet.node.inet.StandardHost;

import inet.linklayer.ethernet.EthernetInterface;

import inet.networklayer.configurator.ipv4.Ipv4NetworkConfigurator;

network FlowBasedRoutingNetwork

{

parameters:

int numRouters = 4;  // Define the number of routers

submodules:

configurator: Ipv4NetworkConfigurator {

@display(“p=50,50”);

}

host1: StandardHost {

@display(“p=50,50”);

}

host2: StandardHost {

@display(“p=400,50”);

}

router[numRouters]: Router {

@display(“p=100+100*i,150”);

}

connections allowunconnected:

host1.ethg++ <–> EthernetInterface <–> router[0].ethg++;

router[0].ethg++ <–> EthernetInterface <–> router[1].ethg++;

router[1].ethg++ <–> EthernetInterface <–> router[2].ethg++;

router[2].ethg++ <–> EthernetInterface <–> router[3].ethg++;

router[3].ethg++ <–> EthernetInterface <–> host2.ethg++;

}

Explanation:

• StandardHost: Denotes the source and destination hosts.
• Router: Signifies routers within the network, which forward traffic according to the flow characteristics.
• EthernetInterface: Wired Ethernet connections among routers and hosts.
• Ipv4NetworkConfigurator: Automatically sets up IP addresses and routing for the nodes.

3. Flow-Based Routing Logic

In flow-based routing, routers create forwarding decisions according to the flows instead of individual packets. Flows may be described by:

• Source and destination address pairs.
• Traffic classes (e.g., high-priority traffic gets different treatment).
• QoS requirements (e.g., bandwidth, latency).
• Time-based or session-based rules.

To replicate flow-based routing, we can tailor routing behaviour by either changing the existing routing protocols in INET or executing the own flow-based routing strategy. For this instance, let’s replicate a simple flow-based routing scenario using custom rules.

4. Configure Flow-Based Routing in omnetpp.ini

We can tailor the routing behaviour by changing the default routing tables or using Custom Routing Table Entries according to the flow definitions (source-destination pairs, specific port numbers, etc.).

Example omnetpp.ini for Flow-Based Routing:

[General]

network = FlowBasedRoutingNetwork

sim-time-limit = 300s

# IP Address Configuration for Hosts and Routers

*.host1.ipv4.address = “10.0.0.1”

*.host1.ipv4.netmask = “255.255.255.0”

*.host2.ipv4.address = “10.0.0.2”

*.host2.ipv4.netmask = “255.255.255.0”

# Custom Routing Table for Flow-Based Routing

*.router[0].routingTableConfigurator.routes = xmldoc(“routes.xml”)

# Traffic Configuration (UDP Traffic Generation)

*.host1.numApps = 1

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

*.host1.app[0].destAddresses = “10.0.0.2”  # Send traffic to Host2

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

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

*.host1.app[0].sendInterval = exponential(1s)

*.host2.numApps = 1

*.host2.app[0].typename = “UdpSink”

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

# Configure QoS or Flow Properties (Optional)

*.router[*].qosClassifier.typename = “DiffservClassifier”  # Example: DiffServ for flow classification

*.router[*].qosQueue.typename = “PriorityQueue”

*.router[*].qosQueue.numQueues = 2

*.router[*].qosQueue.queue[0].packetCapacity = 100

*.router[*].qosQueue.queue[1].packetCapacity = 50

 

Explanation:

• Custom Routing Table: This utilizes the XML-based routing configuration (routes.xml) to describe flow-specific routes.
• Traffic Generation: Host1 transmits UDP traffic to Host2 that is forwarded according to flow rules configured in the routers.
• QoS Classifier and Queue: It is an optional QoS-based configuration in which routers classify and prioritize flows depends on predefined rules (e.g., using DiffServ for traffic prioritization).

5. Define Custom Routing Rules in XML

To execute flow-based routing, we can describe custom rules within an XML file (e.g., routes.xml). The rules can identify forwarding behaviour according to the source-destination pairs, traffic types, and other flow attributes.

Example routes.xml for Flow-Based Routing:

<config>

<interface name=”eth0″>

<route destination=”10.0.0.0″ netmask=”255.255.255.0″ gateway=”10.0.0.2″ metric=”1″/>

</interface>

<interface name=”eth1″>

<route destination=”10.0.0.0″ netmask=”255.255.255.0″ gateway=”10.0.0.3″ metric=”2″/>

</interface>

</config>

Explanation:

• Custom Routes: Describe the particular routes for each interface that would be utilized for flow-based decisions. For instance, we can route traffic destined for 10.0.0.2 via distinct gateways according to the flow priorities or other parameters.

6. Run the Simulation

1. Build the Project:
   • Right-click on the OMNeT++ project and select Build Project to compile the simulation files.
2. Run the Simulation:
   • Right-click on omnetpp.ini and choose Run As > OMNeT++ Simulation.
   • Utilize the Qtenv graphical interface to monitor how traffic flows are sent rely on custom routing rules.

7. Analyze the Results

When the simulation is complete then we can investigate numerous features of the flow-based routing:

1. Flow-Based Routing Table Convergence:
   • Check that each router follows the flow-based routing rules described within the XML file.
2. QoS Treatment of Flows:
   • If QoS was configured then we examine how traffic flows were categorised and prioritized in the network.
3. Traffic Flow:
   • Monitor the flow of traffic from Host1 to Host2 and make certain that it follows the custom-defined routes.
4. Performance Metrics:
   • End-to-End Delay: Calculate how long it takes for packets to travel via the network.
   • Throughput: Investigate the data throughput for each flow.
   • Queueing Delays: If QoS was utilized then estimate the delay introduced by queueing according to the flow prioritization.

8. Extend the Simulation

1. Simulate Dynamic Flow-Based Routing:
   • Execute dynamic flow-based routing in which routing decisions are fine-tuned in the course of runtime depends on traffic conditions or link failures.
2. Multi-Flow Scenarios:
   • Launch several traffic flows with distinct QoS requirements and priorities, and examine how the network manages competing flows.
3. SDN-Based Flow Control:
   • Replicate flow-based routing within an SDN (Software Defined Networking) environment, in which a central controller creates flow-based forwarding decisions dynamically.
4. Network Congestion and Traffic Engineering:
   • Launch network congestion and monitor how flow-based routing enhances traffic engineering to manage high traffic loads.

Through this general methodology using relevant example coding for Flow Based Routing Projects was showcased and simulated within OMNeT++. Also more essential details on this projects to be provided in another manual.

We provide support for performance analysis tailored to your project needs, encouraging you to maintain communication with us for personalized services. For optimal outcomes in Flow Based Routing Projects utilizing OMNeT++ simulation, please reach out to phdprime.com. Our team specializes in Software Defined Networking (SDN).