How to implement igp protocol in ns2

To implement an Interior Gateway Protocol (IGP) like OSPF (Open Shortest Path First) or IS-IS (Intermediate System to Intermediate System) within the simulation tool NS2 (Network Simulator 2) has needs to encompass setting up a network topology and set up routing behaviour to mimic the IGP. Because the simulator NS2 doesn’t natively assist IGPs such as OSPF or IS-IS out of the box, we can mimic the IGP-like behaviour via distance-vector or link-state routing protocols where NS2 assists or by scripting the behaviour. The followings are general method to mimic IGP-like behaviour in NS2:

Step-by-Step Implementations:

  1. Set Up the NS2 Environment:
  • Make certain NS2 is installed on the system. From the official website or via package managers for the operating system, we can install it.
  1. Create the Network Topology:
  • State a network topology in which the nodes are denote routers in the same Autonomous System (AS). Every node will involve in the IGP.

Example:

set ns [new Simulator]

set nf [open out.nam w]

$ns namtrace-all $nf

# Create nodes (routers)

set R1 [$ns node]

set R2 [$ns node]

set R3 [$ns node]

set R4 [$ns node]

set R5 [$ns node]

# Create links between nodes

$ns duplex-link $R1 $R2 1Mb 10ms DropTail

$ns duplex-link $R2 $R3 1Mb 10ms DropTail

$ns duplex-link $R3 $R4 1Mb 10ms DropTail

$ns duplex-link $R4 $R5 1Mb 10ms DropTail

$ns duplex-link $R1 $R3 1Mb 10ms DropTail

  1. Configure IGP-like Routing Behavior:
  • Using Distance-Vector Protocol (DV): The simulation tool NS2 assist distance-vector routing which is similar to RIP. We can permit the DV routing on nodes and let NS2 manage the route calculations.

Example:

$R1 rtproto DV

$R2 rtproto DV

$R3 rtproto DV

$R4 rtproto DV

$R5 rtproto DV

  • Using Static Routing (for Control): If we need more control or to mimic particular IGP behaviours, we can set the routing tables by hand.

Example:

$R1 add-route $R5 1 $R2

$R2 add-route $R5 1 $R3

$R3 add-route $R5 1 $R4

$R4 add-route $R1 1 $R3

  1. Implement Link-State Routing Simulation (Optional):
  • To mimic the link-state protocol such as OSPF, we can writing the link-state advertisements (LSAs) and updates manually, via this is difficult. We can mimic the flooding of LSAs through the network and the estimation of shortest paths based on the network graph.

Example (Pseudocode):

proc send_lsa {router} {

global ns R1 R2 R3 R4 R5

# Simulate sending an LSA from router to all neighbors

foreach neighbor [list $R2 $R3] {

$ns at [expr now + 0.1] “receive_lsa $neighbor”

}

}

proc receive_lsa {router} {

puts “LSA received by $router”

# Update routing table based on LSA

# Calculate shortest path (Dijkstra’s algorithm can be implemented here)

}

# Simulate LSA flooding

$ns at 1.0 “send_lsa $R1”

  1. Simulate Network Traffic:
  • Describe traffic flows among the nodes to monitor how routing happens based on the IGP behaviour. We can attach agents to the nodes and make the traffic flows.

Example:

set udp0 [new Agent/UDP]

$ns attach-agent $R1 $udp0

set null0 [new Agent/Null]

$ns attach-agent $R5 $null0

$ns connect $udp0 $null0

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 512

$cbr set rate_ 1Mb

$cbr attach-agent $udp0

$ns at 1.0 “$cbr start”

  1. Run the Simulation:
  • To run the simulation and we use the trace files or NAM (Network Animator) to visualize how packets are routed via the network.

Example:

$ns at 10.0 “finish”

$ns run

  1. Analyse and Validate:
  • To investigate the trace files to make sure that the routing behaviour relates to the expectations. Verify how the network converges after alters, and if the routes are updated appropriately .
  1. Enhance the Simulation:
  • Dynamic Topology Changes: Mimic link failures or node failures to observe how the network adjusts.
  • Advanced Routing Logic: Execute the further routing characteristics like load balancing or route redistribution if required.

Hence, this module you get more ideas and knowledge on how to implement and evaluate the IGP protocol with the support of these implementation approaches using the simulation tool ns2. More informations and procedure will be provided based on your needs. Allow our professionals to implement your IGP protocol in the ns2 tool. ns2project.com will provide you with the best implementation support for your project ideas. Give us all of the details about your project, and our developers will help you analyze it and find the best solutions.