To simulate Layer 3 (L3) protocols using NS2 that encompasses functioning with network-layer protocols responsible for routing packets over networks. These protocols are important in finding out how packets are sent among distinct networks, and instance contain IP (Internet Protocol), RIP (Routing Information Protocol), OSPF (Open Shortest Path First), and BGP (Border Gateway Protocol).
The following is a guide to simulating L3 protocols in NS2:
Steps to Simulate Layer3 Protocols Projects in NS2
- Install NS2
Make certain that NS2 is installed on the machine. We can download it from the NS2 official website.
- Choose a Layer 3 Protocol
Generally used Layer 3 routing protocols in NS2 involve:
- RIP (Routing Information Protocol) for distance-vector routing.
- OSPF (Open Shortest Path First) for link-state routing.
- BGP (Border Gateway Protocol) for inter-domain routing.
- AODV (Ad-hoc On-demand Distance Vector Routing) for mobile ad-hoc networks.
For this instance, we will be replicate RIP (Routing Information Protocol) in a network.
- Set Up a Basic L3 Network Topology
We require to make a network topology with routers, and set up the L3 routing protocol (e.g., RIP). Here’s how to configure a basic network of routers using RIP.
Example TCL Script for L3 Network Topology (RIP):
# Create a new simulator instance
set ns [new Simulator]
# Define trace and nam files for logging and visualization
set tracefile [open l3_simulation.tr w]
$ns trace-all $tracefile
set namfile [open l3_simulation.nam w]
$ns namtrace-all $namfile
# Create nodes representing routers
set r1 [$ns node] ;# Router 1
set r2 [$ns node] ;# Router 2
set r3 [$ns node] ;# Router 3
# Create duplex links between the routers
$ns duplex-link $r1 $r2 10Mb 10ms DropTail
$ns duplex-link $r2 $r3 10Mb 10ms DropTail
$ns duplex-link $r1 $r3 10Mb 20ms DropTail
# Enable RIP routing protocol between the routers
$ns rtproto RIP
# Set node positions (optional)
$r1 set X_ 100; $r1 set Y_ 200; $r1 set Z_ 0.0
$r2 set X_ 200; $r2 set Y_ 200; $r2 set Z_ 0.0
$r3 set X_ 300; $r3 set Y_ 200; $r3 set Z_ 0.0
This example sets up RIP as the routing protocol for Layer 3. We can also substitute RIP with OSPF, BGP, or other protocols based on the requirements.
- Configure Traffic Between Routers
After configuring the network topology then we require to replicate traffic among the routers to observe how the L3 routing protocol forwards packets.
Example for TCP Traffic:
# Set up TCP connection between router r1 and router r3
set tcp0 [new Agent/TCP]
set sink0 [new Agent/TCPSink]
$ns attach-agent $r1 $tcp0
$ns attach-agent $r3 $sink0
$ns connect $tcp0 $sink0
# Create FTP traffic over TCP
set ftp0 [new Application/FTP]
$ftp0 attach-agent $tcp0
$ns at 2.0 “$ftp0 start”
$ns at 10.0 “$ftp0 stop”
This replicates TCP traffic among r1 and r3, and RIP will find out the routes.
- Run the Simulation
When the TCL script is prepared then we save it (e.g., l3_simulation.tcl) and run it in NS2:
ns l3_simulation.tcl
It will make trace (.tr) and NAM (.nam) files that we can examine and visualize using Network Animator (NAM).
- Analyze the Simulation Results
To estimate the performance of the Layer 3 protocol, we can assess:
- Packet Delivery Ratio (PDR)
- End-to-End Delay
- Routing Overhead
- Route Convergence Time
Example AWK Script for Packet Delivery Ratio:
BEGIN { sent = 0; received = 0; }
{
if ($1 == “s” && $4 == “AGT”) { sent++; }
if ($1 == “r” && $4 == “AGT”) { received++; }
}
END { print “Packet Delivery Ratio = “, received/sent*100, “%”; }
This script will compute the Packet Delivery Ratio (PDR) by comparing the amount of packets transmitted and received.
- Example Project Ideas for L3 Protocol Simulation
- Performance Comparison of RIP and OSPF:
- Replicate a network with both RIP and OSPF and compare their performance such as route convergence time, packet delivery ratio, and delay.
- BGP Simulation for Inter-Domain Routing:
- Mimic BGP for routing among distinct ASes and investigate how route advertisements and withdrawals affect traffic flows.
- Mobile Ad-Hoc Network (MANET) with AODV:
- Model a mobile ad-hoc network utilizing AODV and examine how the network adapts to modifying topologies because of node mobility.
- Energy Efficiency in L3 Routing:
- Execute an energy-aware routing at Layer 3 and calculate its influence on network lifetime in wireless sensor networks or MANETs.
The network simulator NS2 was used to simulate and evaluate the Layer3 protocols projects using the above procedure and example projects ideas for L3 protocol. We are available to offer more detailed informations as needed.
IP (Internet Protocol), RIP (Routing Information Protocol), OSPF (Open Shortest Path First), and BGP (Border Gateway Protocol) guidance are worked by us, so get best simulation guidance from us.
