How to Implement Next Hop Protocol in NS2

To implement the Next Hop protocol in NS2 that has encompasses making a protocol, where ascertains the next hop for packet forwarding according to the particular criteria. This protocol concept is normally portion of several existing routing protocols. However, we can execute a custom version concentrating solely on the next hop selection logic. The given approach is supports on how we can implement it in ns2:

Step-by-Step Implementation:

Step 1: Understand the Next Hop Protocol

The Next Hop protocol that needs to includes determining the finest next node (hop) to send a packet to its terminus. This decision can be rely on numerous parameters, like shortest path, minimum delay, highest bandwidth, or a combination of factors.

Step 2: Set Up NS2

Make certain that NS2 is installed on the computer. If essential, then apply patches or extend NS2 to append the support for custom protocols.

Step 3: Implement the Next Hop Agent Class (C++)

We want to make a C++ class in NS2 that executes the Next Hop logic. The class would manage the following:

  • Next Hop Selection: According to a routing metric or criteria.
  • Packet Forwarding: Directing packets to the chosen next hop.

Below is a simple structure:

#include <agent.h>

#include <packet.h>

#include <trace.h>

#include <address.h>

class NextHopAgent : public Agent {

public:

NextHopAgent();

void recv(Packet* p, Handler* h);

void forwardPacket(Packet* p);

int selectNextHop(Packet* p);

protected:

// Any additional data structures or variables needed for next hop selection

};

// Constructor

NextHopAgent::NextHopAgent() : Agent(PT_UDP) {

// Initialization code here

}

// Packet reception

void NextHopAgent::recv(Packet* p, Handler* h) {

forwardPacket(p);

}

// Forward packet to the selected next hop

void NextHopAgent::forwardPacket(Packet* p) {

int nextHop = selectNextHop(p);

// Code to forward the packet to the next hop

}

// Select the best next hop based on your criteria

int NextHopAgent::selectNextHop(Packet* p) {

// Implement your next hop selection logic here

// For example, selecting the neighbor with the shortest path to the destination

return next_hop_id;  // Placeholder for the selected next hop node ID

}

Step 4: Integrate the Next Hop Agent into NS2

  1. Modify the Makefile: Append the new NextHopAgent class to the NS2 Makefile so as to it acquires compiled with the rest of the simulator.
  2. Recompile NS2:

make clean

make

Step 5: Create a Tcl Script to Simulate the Next Hop Protocol

When the Next Hop protocol is executed and compiled, make a Tcl script to replicate the network using this protocol.

Example Tcl Script:

# Create a simulator object

set ns [new Simulator]

# Define the topology

set val(chan)   Channel/WirelessChannel

set val(prop)   Propagation/TwoRayGround

set val(netif)  Phy/WirelessPhy

set val(mac)    Mac/802_11

set val(ifq)    Queue/DropTail/PriQueue

set val(ll)     LL

set val(ant)    Antenna/OmniAntenna

set val(ifqlen) 50

set val(nn)     10

set val(x)      1000

set val(y)      1000

set val(stop)   100.0

set val(rp)     NextHop   ;# Routing protocol

# Initialize the topology object

set topo [new Topography]

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

# Create the God object

create-god $val(nn)

# Configure the nodes

$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 \

-movementTrace ON

# Create nodes

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

set node_($i) [$ns node]

}

# Define node positions and movement model

$node_(0) set X_ 100.0; $node_(0) set Y_ 200.0

$node_(1) set X_ 200.0; $node_(1) set Y_ 300.0

$node_(2) set X_ 300.0; $node_(2) set Y_ 400.0

$node_(3) set X_ 400.0; $node_(3) set Y_ 500.0

$node_(4) set X_ 500.0; $node_(4) set Y_ 600.0

# Set up traffic sources

set udp [new Agent/UDP]

$ns attach-agent $node_(0) $udp

set null [new Agent/Null]

$ns attach-agent $node_(4) $null

$ns connect $udp $null

set cbr [new Application/Traffic/CBR]

$cbr attach-agent $udp

$cbr set packetSize_ 512

$cbr set interval_ 0.1

$cbr start

# Simulation end

$ns at $val(stop) “stop”

$ns at $val(stop) “$ns nam-end-wireless $val(stop)”

$ns at $val(stop) “exit 0”

proc stop {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

}

# Run the simulation

$ns run

Step 6: Run the Simulation

  1. We can save the Tcl script like nexthop_example.tcl.
  2. Open a terminal and navigate to the directory in which we can saved the Tcl script.
  3. Run the simulation using the below command:

ns nexthop_example.tcl

Step 7: Analyse the Results

  • We can use the trace files and the network animator (NAM) to test the performance of the Next Hop protocol, concentrating on the parameters like packet delivery ratio, end-to-end delay, and routing overhead.
  • Observe how successfully the protocol manages the network changes and node mobility.

Additional Considerations

  • Next Hop Selection Criteria: The performance of the protocol heavily rely on the criteria used for choosing the next hop. Test with various parameters to enhance the performance.
  • Performance Comparison: Liken the Next Hop protocol with other routing protocols to assess its effectiveness and scalability.

We applied a sequential method to next hop protocol which was then implemented and estimated using the virtual environment ns2. If you want further guidance on this topic, we will provide.

Let us handle your performance analysis! We deliver outstanding results for Hop Protocol in NS2 implementation. Reach out to ns2project.com for the best project ideas and topics. Our expertise lies in routing protocols.