How to Implement Network Rendezvous Discovery in NS2

To implement the Network Rendezvous Discovery in NS2 which means to the process in which the nodes in a networks finds all other to accomplish communication commonly used in mobile ad hoc networks (MANETs), sensor networks or peer-to-peer (P2P) systems. This can be done by replicating how nodes find one another using beaconing or broadcasting, after they accomplish a communication link. This concept is alike to neighbor discovery protocols or rendezvous mechanisms in distributed networks. Utilize the given script to implement this in ns2:

Key Concepts for Network Rendezvous Discovery in NS2:

  1. Beaconing or Broadcasting: Nodes occasionally broadcast beacon messages to announce their presence, and other nodes can listen for these messages to begin communication.
  2. Node Discovery: When a node obtains a beacon from another node, it finds that node and initiates communication (such as configure a TCP or UDP connection).
  3. Rendezvous Point: This could be a fixed point or a dynamic mechanism where nodes meet (either physically in mobile networks or virtually in static networks) to start communication.

Steps to Implement Network Rendezvous Discovery in NS2

  1. Node Beaconing/Broadcasting: Simulate nodes broadcasting periodic messages to declare their presence.
  2. Discovery Mechanism: Other nodes listen for beacon messages and discover the broadcasting node.
  3. Communication Setup: Once discovery is made, nodes develop a communication channel (like TCP or UDP) to interchange data.
  4. Dynamic Discovery: In mobile networks, simulate nodes traveling around and discovering each other when they come into range.

Example: Simulating Network Rendezvous Discovery in NS2

In this sample, nodes intermittently broadcast beacons, and other nodes that receive these beacons accomplish communication. We will replicate a basic rendezvous discovery process where two nodes discover one another through periodic broadcasts.

Step 1: Define Nodes and Set Up Broadcast Mechanism

# Define the simulator object

set ns [new Simulator]

# Define trace and nam files for output

set tracefile [open out.tr w]

set namfile [open out.nam w]

$ns trace-all $tracefile

$ns namtrace-all $namfile

# Define a ‘finish’ procedure to end the simulation and visualize in NAM

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam out.nam &

exit 0

}

# Set up the topography for the simulation area

set topo [new Topography]

$topo load_flatgrid 500 500

# Define the wireless channel

set chan [new Channel/WirelessChannel]

# Configure wireless nodes for ad-hoc communication using AODV routing protocol

$ns node-config -adhocRouting AODV \

-llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 50 \

-antType Antenna/OmniAntenna \

-propType Propagation/TwoRayGround \

-phyType Phy/WirelessPhy \

-channel $chan

# Create two nodes that will rendezvous

set node1 [$ns node]

set node2 [$ns node]

# Set node positions for NAM visualization

$node1 set X_ 100; $node1 set Y_ 100; $node1 set Z_ 0

$node2 set X_ 400; $node2 set Y_ 400; $node2 set Z_ 0

# Step 2: Simulate Node Broadcasting (Beaconing)

# Node1 will broadcast its presence

proc broadcast_presence {node} {

puts “Node $node is broadcasting its presence.”

}

# Schedule periodic broadcasts for Node1

for {set i 1} {$i <= 5} {incr i} {

$ns at [expr $i * 1.0] “broadcast_presence $node1”

}

# Step 3: Define Discovery Mechanism for Node2

# Node2 listens for broadcasts from Node1 and initiates communication upon discovery

proc discover_node {node src} {

puts “Node $node has discovered node $src and is initiating communication.”

# Set up TCP communication from Node2 to Node1 after discovery

set tcp [new Agent/TCP]

set sink [new Agent/TCPSink]

$ns attach-agent $node $tcp

$ns attach-agent $src $sink

$ns connect $tcp $sink

# Start FTP traffic after discovery

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ftp start 2.0   ;# Start FTP traffic at 2 seconds

$ftp stop 5.0    ;# Stop FTP traffic at 5 seconds

}

# Simulate Node2 discovering Node1 at 2 seconds (after receiving a beacon)

$ns at 2.5 “discover_node $node2 $node1”

Step 2: Schedule the End of the Simulation

# Schedule the end of the simulation

$ns at 10.0 “finish”

# Run the simulation

$ns run

Explanation of the Script

  1. Beaconing (Broadcasting Presence):
    • Node1 sporadically broadcasts a beacon using the broadcast_presence procedure. This replicates the node announcing its presence to the network.
  2. Discovery:
    • Node2 listens for these beacons and upon obtaining one, begins communication with Node1 using the discover_node procedure. This procedure configures a TCP connection amongst Node2 and Node1.
  3. Communication Setup:
    • Once Node2 discovers Node1, it starts an FTP application on top of TCP to replicate data exchange amongst the nodes after rendezvous discovery.

Run the Simulation

Store the script as rendezvous_discovery.tcl and execute it using:

ns rendezvous_discovery.tcl

This will produce a trace file (out.tr) and a NAM file (out.nam). The trace file stores the packet transmissions, and the NAM file permits you to visualize the discovery and communication amongst nodes.

Visualize the Simulation in NAM

To visualize the simulation in NAM, use the following command:

nam out.nam

In NAM, you will monitor Node1 broadcasting its presence, and Node2 discovering it, followed by the establishment of communication amongst them.

Advanced Features for Rendezvous Discovery

  1. Dynamic Node Mobility: Introduce node mobility where nodes move in and out of each other’s communication range. Rendezvous discovery can happen when nodes come within range of each other.

Example:

$ns at 0.0 “$node1 setdest 200 200 5.0”

$ns at 0.0 “$node2 setdest 200 200 3.0”

  1. Multi-node Discovery: Extend the simulation to several nodes where all nodes occasionally broadcast beacons and find each other.
  2. Energy-aware Discovery: Replicate energy constraints where nodes restrict their broadcasting to conserve energy, making rendezvous discovery more threatening.
  3. Custom Rendezvous Protocols: Execute custom discovery protocols where nodes negotiate a rendezvous point or time depends on network conditions or predefined rules.

Through the above manual, you can obtain and learn how to configure the simulation environment, including sample snippets for the implementation of Network Rendezvous Discovery using ns2 tool. You can also include their modern strategies for future enhancements.

We provide in-depth analysis of your network performance with easy-to-understand explanations. Our expertise lies in simulating network protocols, so reach out to us for help with implementing Network Rendezvous Discovery in NS2.