How to Start SDN Projects Using NS2

To stimulate a Software-Defined Networking (SDN) project using NS2 (Network Simulator 2) needs multiple methods to setting a replication environment which helps for SDN concepts, like as centralized control, programmable data planes, and network management via a controller. Though NS2 does not natively help for the SDN, we can encompass through further component or modify the scripts and replicate the SDN-based networks.

Here’s a step-by-step guide to start an SDN project using NS2:

Steps to Start SDN Projects Using NS2

  1. Install NS2

Previously beginning any project in NS2, we require having a NS2 installed on the system. If we do not have the NS2 installed yet, follow this procedure:

  • For Linux: Use the following command to install:

sudo apt-get install ns2

  • For macOS/Windows: We can install NS2 tool using a virtual machine or through Cygwin for sample for Windows.

Validate the installation through processing a basic sample scripts for sample ns simple.tcl to enable the NS2 is operates correctly.

  1. Understand the Basics of SDN

Previously spilt the SDN replication in NS2, it is crucial to understand the main concepts for the Software-Defined Networking (SDN):

  • Control Plane: This is the SDN controller in which resides. It creates the high-level decisions about the network such as routing, flow management.
  • Data Plane: The network devices for sample switches/routers which sending the packets according to the rules received from the controller.
  • SDN Controller: The centralized entity which has a global vision for the network and it can install the flow rules into switches.
  • OpenFlow: The general protocol used in SDN for transmission among the controller and switches. It assigns the controller for dynamically alter the flow rules in switches.

SDN projects generally focus on:

  • Traffic Engineering: Enhance the network paths according to the real-time metrics.
  • Network Virtualization: Handled the several virtual networks on top of the physical network.
  • Load Balancing: Assure the congestion for evenly distribution with the network.
  1. Install SDN-Specific Extensions for NS2

NS2 does not have natively SDN helps for out-of-the-box; nevertheless we can encompass through incorporate the external modules which improve the SDN functionality. Some decisions are include:

  • OpenFlow module for NS2: This module replicates the SDN-based networks through improve the OpenFlow helps for switches and controllers. The incorporate for OpenFlow into NS2 permits the replication of SDN environments in which the central controller interacts by OpenFlow-enabled switches.

We can download this module from sources such as GitHub or NS2-related repositories. For instance:

To install the OpenFlow extension:

  1. Download the OpenFlow NS2 module from the repository.
  2. Follow the installation procedures in the README file such as usually involves compiling the NS2 module.
  3. After installed, we can initialize the OpenFlow commands in the NS2 scripts.
  • NS2 with Mininet: Mininet is a network emulator for SDN that builds a virtual SDN networks. Although Mininet operates separately from the NS2, we can use it together with NS2 and SDN replication. Mininet permits the replication of large-scale SDN networks and OpenFlow behavior.
  1. Set up SDN Topology

Intended for an SDN project, we will require to topology in which replicate the SDN components like as switches, routers, and a centralized controller. Here’s on how can replicate the simple for SDN topology:

  • SDN Switches: This node in the network which uses OpenFlow for sending the packets according to the flow rules.
  • SDN Controller: The central controller will transfer the OpenFlow commands to the switches for handle their behavior.
  • Hosts: Which devices are forward and receive the congestion in the network.

Basic SDN Topology Example:

  1. Builds a multiple switches for sample which will be OpenFlow-enabled.
  2. Increase the SDN controller.
  3. Join the hosts for the switches.

Example Tcl script to simulate an SDN topology with NS2 and OpenFlow:

# Load OpenFlow module

package require openflow

# Create the simulator instance

set ns [new Simulator]

# Create nodes: SDN controller, switches, and hosts

set controller [new Agent/OpenFlowController]

set switch1 [new Agent/OpenFlowSwitch]

set switch2 [new Agent/OpenFlowSwitch]

set host1 [$ns node]

set host2 [$ns node]

# Attach the switches and the controller

$ns attach-agent $switch1 $controller

$ns attach-agent $switch2 $controller

# Set up connections between switches and hosts

$ns duplex-link $host1 $switch1 10Mb 10ms DropTail

$ns duplex-link $host2 $switch2 10Mb 10ms DropTail

$ns duplex-link $switch1 $switch2 20Mb 5ms DropTail

# Set up traffic between hosts

set udp1 [new Agent/UDP]

$ns attach-agent $host1 $udp1

set cbr1 [new Application/Traffic/CBR]

$cbr1 attach-agent $udp1

$ns at 1.0 “$cbr1 start”

$ns at 2.0 “$cbr1 stop”

# Run the simulation

$ns run

Explanation:

  • We describe the OpenFlow controller (OpenFlowController).
  • It contains the two switches for sample OpenFlowSwitch are generated, that will communicate by the controller using the OpenFlow.
  • The two hosts are linked to switches, and congestion is created among hosts.
  • The OpenFlow ensure the switches for sending the congestion traffic according to the flow for entries provided through the controller.
  1. Implement SDN Controller Logic

The SDN controller is responsible for handling the flow entries in switches. In a real SDN environment, the controller communicates by switches using OpenFlow to install, modify, or remove flow rules.

In NS2, we can apply a simplified SDN controller through improve alter logic for handled the flow tables. For sample, the controller might install flow entries according to network environments or routing decisions.

Example of SDN controller logic:

# Create a function to install flow rules into switches

proc installFlowRule {switch src_ip dst_ip action} {

# Install flow rule to match source and destination IP

puts “Installing flow rule: Match: src=$src_ip, dst=$dst_ip, action=$action”

# This can involve updating the OpenFlow flow table

}

# Simulate flow installation from the controller

installFlowRule $switch1 “192.168.1.1” “192.168.2.1” “forward”

This is simple sample for flow rule installation, and further advanced replication, we would incorporate by OpenFlow operations and connection for replicated simulated network action for sample based on packet arrivals.

  1. Simulate SDN Concepts

After we have setting the topology, we can replicate the different SDN structures, like as:

  • Flow table management: The SDN controllers are increase, alter or remove for the rules flow in the switches.
  • Traffic Engineering: The SDN controller can improve the paths through altering for flow entries according to the real-time network conditions.
  • Load Balancing: The SDN controller has dynamically rerouted for the congestion balancing the load with switches.
  • Network Monitoring and Performance Metrics: Gather the performance metrics for sample latency, throughput, packet loss we examine the behavior for the SDN system.
  1. Run the Simulation

After the script is ready, we can process for the replication:

ns sdn_project.tcl

NS2 will create the trace files for sample usually in .tr format that contains the complete information for the replication it including the packet transfers, flow rules, and network events.

  1. Analyze the Results

We can examine the replication outcomes using tools such as:

  • AWK: We explain the trace files and excerpt parameter metrics like as throughput, latency, and packet loss.
  • XGraph: It built-in the NS2 tool for envisions the network performance based on the parameter metrics like as throughput, packet delay, and loss.

For example, to visualize throughput, you can run:

awk ‘{print $1, $2, $3, $4}’ tracefile.tr | xgraph

  1. Extend the Simulation

Next the simple setting, we can encompass the SDN replication has includes the further advanced structures:

  • Multiple SDN Controllers: We can replicate the network by several SDN controllers and handled the congestion with regions.
  • Flow Priority and QoS: Apply the quality-of-service (QoS) mechanisms in which the controller handles the high-priority traffic flows.
  • Network Failure and Recovery: Replicate the network failures and use the SDN’s for flexibility to dynamically resetting the network.

Conclusion

Starting an SDN project in NS2 requires setting up an SDN-enabled network with OpenFlow switches and a centralized controller. Since NS2 doesn’t natively support SDN, you need to extend NS2 with OpenFlow modules or integrate it with other SDN frameworks like Mininet. By following these steps, you can simulate SDN-based networks and explore concepts like flow management, traffic engineering, and load balancing within the SDN framework.

Through the entire manual, we all know the general concepts that can help you to enhance the knowledge about the simulation process for Software-Defined Networking using the tool of ns2. Additional specific details about the mixed topology will also be provided.