How to Implement Reputation based Routing in NS2

To implement the Reputation-based routing in NS2 has a series of steps to follow that improves trust-based routing by establishing a reputation system in which nodes assess their neighbours based on observed behaviours like packet forwarding, dropping, or delay. Nodes allocate their reputation values with other nodes, and routes are prioritizing based on the collective reputation scores of the nodes in the route. This system supports to avoid malicious nodes from being designated for routing and guarantees more reliable network communication.

Here is guide to implement a simple Reputation-based routing in NS2:

Steps to Implement Reputation-Based Routing in NS2

  1. Set up NS2 Environment

Make sure that NS2 is installed and configured on system. Reputation-based routing usually contains to adjust existing routing protocols such as AODV or DSR to include a reputation metric that influences the route selection process.

  1. Reputation System
  • Reputation Metric: Each node maintains a reputation value for its neighbors based on their observed behaviors, like packet forwarding, dropping, or delays.
  • Reputation Sharing: Nodes can distribute reputation information with each other that permits for a more global view of the network.
  • Route Selection: Routes are selected according to the reputation scores of the nodes in the path. Nodes with a low reputation like due to misbehavior are evaded in routing decisions.
  1. Create a TCL Script for Reputation-based Routing

The following sample determines how to simulate reputation-based routing in NS2 by adjusting the AODV routing protocol to contain reputation metrics in route selection.

Example TCL Script for Reputation-based Routing:

# Create a new NS2 simulator

set ns [new Simulator]

#Open trace and NAM output files

set tracefile [open reputation_routing.tr w]

$ns trace-all $tracefile

set namfile [open reputation_routing.nam w]

$ns namtrace-all $namfile

# Define wireless network parameters

set val(chan)   Channel/WirelessChannel

set val(prop)   Propagation/TwoRayGround

set val(ant)    Antenna/OmniAntenna

set val(netif)  Phy/WirelessPhy

set val(mac)    Mac/802_11

set val(ifq)    Queue/DropTail/PriQueue

set val(ifqlen) 50

set val(ll)     LL

set val(rp)     AODV                       ;# Use AODV with reputation-based modifications

set val(x)      1000

set val(y)      1000

set val(num_nodes) 10                      ;# Number of nodes

# Create topography for the network

set topo [new Topography]

$topo load_flatgrid $val(x) $val(y)

# Configure node parameters

$ns node-config -adhocRouting $val(rp) \

-llType $val(ll) \

-macType $val(mac) \

-ifqType $val(ifq) \

-ifqLen $val(ifqlen) \

-antType $val(ant) \

-propType $val(prop) \

-phyType $val(netif) \

-channelType $val(chan) \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON

# Create nodes and set initial positions

for {set i 0} {$i < $val(num_nodes)} {incr i} {

set node($i) [$ns node]

$node($i) set X_ [expr rand() * $val(x)]

$node($i) set Y_ [expr rand() * $val(y)]

$node($i) set Z_ 0

}

# Define initial reputation values for each node (between 0 and 1)

set reputation_values [list 0.9 0.8 0.7 0.6 1.0 0.4 0.5 0.9 0.3 0.8] ;# Reputation scores

# Function to calculate the reputation of a route based on the nodes involved

proc calculate_route_reputation {route_nodes} {

global reputation_values

set total_reputation 0

foreach node $route_nodes {

set node_id [expr $node % 10] ;# Map node ID to the reputation array

set reputation_value [lindex $reputation_values $node_id]

set total_reputation [expr $total_reputation + $reputation_value]

}

return [expr $total_reputation / [llength $route_nodes]] ;# Average reputation for the route

}

# Create UDP agents for communication between node(0) and node(9)

set udp0 [new Agent/UDP]

$ns attach-agent $node(0) $udp0

set null0 [new Agent/Null]

$ns attach-agent $node(9) $null0

$ns connect $udp0 $null0

# Create CBR traffic over UDP

set cbr0 [new Application/Traffic/CBR]

$cbr0 set packetSize_ 512

$cbr0 set rate_ 1Mb

$cbr0 attach-agent $udp0

# Start and stop CBR traffic

$ns at 1.0 “$cbr0 start”

$ns at 9.0 “$cbr0 stop”

# Route discovery with reputation-based decision making

proc reputation_based_route_discovery {src dst} {

global ns reputation_values

set possible_routes [$ns get_routes $src $dst]  ;# Get all possible routes from src to dst

set best_route {}

set best_reputation -1

foreach route $possible_routes {

set route_reputation [calculate_route_reputation $route]

if {$route_reputation > $best_reputation} {

set best_reputation $route_reputation

set best_route $route

}

}

return $best_route

}

# Trigger reputation-based route discovery for communication

set best_route [reputation_based_route_discovery 0 9]

puts “Best route based on reputation: $best_route”

# Schedule simulation end

$ns at 10.0 “finish”

# Define finish procedure to close trace and NAM files

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam reputation_routing.nam &

exit 0

}

# Run the simulation

$ns run

  1. Explanation of Key Components
  • Reputation Values: Each node has an associated reputation score, ranging from 0 (least reputable) to 1 (most reputable). These values can be static or dynamically updated during the simulation.
  • Route Reputation Calculation: The calculate_route_reputation function estimates the average reputation of a route by totalling the reputation scores of the nodes in the route and averaging them.
  • Route Discovery: The reputation_based_route_discovery function priortize the best route according to the reputation scores of the nodes along the path. The route with the highest reputation is selected for data transmission.
  • Communication: UDP-based communication is configures among node (0) and node (9) using CBR traffic to mimic the network communication.
  1. Running the Simulation

Save the script as reputation_routing.tcl and executed it in NS2:

ns reputation_routing.tcl

Once the simulation completes, we can envision the routing decisions and network behavior using NAM:

nam reputation_routing.nam

  1. Dynamic Reputation Update Mechanism

We can expand the script to update reputation values enthusiastically based on observed behaviour such as packet drops, forwarding success, delays, etc. This is vital for real-world scenarios in which reputation changes over time according to node behavior.

Example of Dynamic Reputation Update:

# Function to update a node’s reputation dynamically (e.g., after observing misbehavior)

proc update_reputation {node_id event} {

global reputation_values

set reputation_value [lindex $reputation_values $node_id]

if {$event == “packet_drop”} {

set new_reputation [expr $reputation_value * 0.9] ;# Reduce reputation on packet drop

} elseif {$event == “successful_forward”} {

set new_reputation [expr $reputation_value * 1.05] ;# Increase reputation on successful packet forwarding

} else {

set new_reputation $reputation_value

}

lset reputation_values $node_id $new_reputation

puts “Updated reputation for node $node_id: $new_reputation”

}

# Example of invoking the reputation update function

update_reputation 2 “packet_drop”

update_reputation 3 “successful_forward”

This function can be called in response to network events such as packet drops or successful forwards to update the reputation values enthusiastically during the simulation.

  1. Advanced Features for Reputation-Based Routing

We can further improve the reputation-based routing system by executing the following features:

  • Reputation Sharing: Nodes allocate their reputation values with their neighbours that permit them to collaboratively evaluate the reputation of other nodes in the network.
  • Malicious Node Detection: To mimic malicious nodes that outperforms the attacks like dropping packets or delaying transmissions and classifies them according to their reputation scores.
  • Global Reputation Score: Utilize a global reputation system in which nodes maintain a reputation score according to the reports from other nodes, improving reliability in classifying malicious behaviour.

In the end of the simulation, we all learn and get knowledge about the reputation-based routing that is used to make the appropriate decision that enhance the reliability was implemented in ns2 simulation tool. We will elaborate on the reputation-based routing strategy applied in different simulation instances in further manual. If you’re looking to set up Reputation-based Routing in the NS2 tool, feel free to reach out to the ns2project.com team for personalized help. We offer great project ideas, topics, and network comparison results to get you started.