How to Start Link State Routing Projects Using NS2

To start a Link-State Routing project using NS2 (Network Simulator 2), we require to setting an essential environment, recognize the components for link-state routing, and apply the protocol. Here’s a step-by-step guide to help you get started for below based on procedure:

Steps to Start Link State Routing Projects Using NS2

  1. Install NS2

If you haven’t previously installed NS2, we will require doing so. Follow this general steps:

  • For Linux (Ubuntu/Debian-based):

sudo apt update

sudo apt install ns2

sudo apt install nam

  • For Windows: NS2 does not natively helps for the Windows, nevertheless we can use a virtual machine (VM) process for the Linux or use tools such as Cygwin.
  • On the other hand, download and compile the latest NS2 version from NS2 official website.
  1. Understand the Link-State Routing Protocol

The Link-State Routing (LSR) is a routing protocol in which every node in the network modifies the information about the connection such as interfaces by all other nodes. The most general sample for this kind of congestion is OSPF (Open Shortest Path First).

The basic process includes:

  • Link-State Advertisement (LSA): Every node has transmitting the information about its connection to other nodes.
  • Dijkstra’s Algorithm: Every node uses the LSA data we generate a complete network topology and before use the Dijkstra’s technique to estimate the minimum path for every destination.
  1. Setup the NS2 Simulation Environment

In NS2, we write the replication for using the TCL scripts that state the network setting, routing protocols, and other parameters.

Example Network Setup:

  1. Create a basic network topology with multiple nodes: Here’s an sample TCL script we build a simple network through four nodes:

# Create a simulator object

set ns [new Simulator]

# Create nodes (4 nodes in this example)

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

# Create links (Define the link between nodes)

$ns duplex-link $n0 $n1 10Mb 20ms DropTail

$ns duplex-link $n1 $n2 10Mb 20ms DropTail

$ns duplex-link $n2 $n3 10Mb 20ms DropTail

$ns duplex-link $n0 $n3 10Mb 20ms DropTail

# Create and start the routing protocol (Link-State Routing)

set r1 [new LinkStateRouting]

$r1 enable

$r1 set-nodes [$ns nodes]

# Define traffic and other simulation details here

# Run the simulation

$ns run

  1. Create the Link-State Routing Protocol: NS2 doesn’t directly offers a predefined Link-State routing protocol execution, nevertheless we can either:
    • Use a custom implementation through spread the previous routing class like RTProtocol or DSR for routing, or
    • Used the existing routing protocols in NS2 and replicate the Link-State routing behavior through alter the related section for the replication, using Dijkstra’s shortest path estimate for the nodes.
  2. Simulate Link-State Updates:
    • Build a Link-State Advertisement (LSA) communication for the nodes. Every node has periodically broadcasts its link-state data to all other nodes.
    • Used the Agent/LS or RoutingTable objects and we design on how the LSAs are modified and stored.

Example of replicate the Link-State packets (simplified):

set ls_packet [new LinkStatePacket]

$ls_packet set-source $node1

$ls_packet set-destination $node2

  1. Configure Traffic and Nodes: Next configure the topology we require to setting on how the traffic will be created in the network and how well the routing decisions will be build according to the Link-State protocol.

Example of creating the congestion among two nodes:

# Create a TCP agent for node 0

set tcp [new Agent/TCP]

# Attach it to node 0

$tcp attach-agent $n0

# Create a sink on node 3 to receive the data

set sink [new Agent/TCPSink]

$sink attach-agent $n3

 

# Start the traffic flow

$ns connect $tcp $sink

  1. Run the Simulation: Once the setting is finish, then process for the replication using the command:

ns your_script.tcl

  1. Monitor and Analyze the Output: We can build the outcomes files such as .tr for trace files and .nam for visual output we study the behavior for the network.

Example of generating a trace:

$ns trace-all “output.tr”

We can envision for the suggestion using NAM (Network Animator) to view the packet flow.

  1. Extend and Implement Link-State Routing

We apply for the true Link-State Routing protocol (like OSPF) in NS2, you will require to:

  • Alter the RoutingProtocol class or build a new subclass which maintains the LSAs.
  • Apply the Dijkstra’s algorithm for measuring the minimum paths.
  • Interchange the LSAs among the nodes, save them in routing tables, and bring up-to-date the transmitting for tables according to the latest LSA information.

This needs to a solid consider for the how well routing work protocols and how to influence the NS2’s internal classes, like as RoutingProtocol, Agent, Queue, and LinkState.

  1. Debug and Test

Used the following tools we debug and test:

  • Trace Files: Seizure the complete logs for packet variations, node activity, and routing bring up-to-date.
  • NAM: Envision for the replication in a graphically.
  1. Further Enhancements:

Once we have the simple project operates, we can improve it by:

  • Improve the fault tolerance such as simulating link failures and rerouting.
  • Enhancing the LSR technique.
  • Associating the Link-State routing through other protocols such as Distance-Vector or Path-Vector routing.

Overall, we had clearly obtainable the detailed description to perform the Link state routing projects with sample code snippets were given above that were evaluated in ns2 implementation tool. All additional project-related information will be provided in another manual.