How to Implement Optical Network in ns2

To implement an optical network in Network Simulator 2 (ns2) has needs to encompass to emulate the communication among the nodes using optical fibers as the transmission medium. While ns2 is primarily intended for emulating the traditional wired and wireless networks, so we can approximate an optical network by setup high-speed links with low error rates and minimal latency to signifies an optical fibers. We can also emulate the wavelength-division multiplexing (WDM) by using numerous links to denote various wavelengths.

Step-by-Step Implementation:

Step 1: Conceptualize the Optical Network Simulation

In a typical optical network:

  1. Optical Nodes (Optical Routers/Switches): These nodes manage optical signals, routing data based on wavelengths (WDM) or switching in an optical domain.
  2. Optical Links: These signify fiber optic cables that are usually high-bandwidth, low-latency links.
  3. Wavelength-Division Multiplexing (WDM): Multiple data streams are routed instantaneously over the same optical fiber using diverse wavelengths that can be simulated using multiple links.

Step 2: Create the Tcl Script

The given below is an example Tcl script that emulates a simple optical network with three optical nodes associated through optical links.

Example Tcl Script for Simulating an Optical Network in ns2

# Create a simulator object

set ns [new Simulator]

# Define the topography object

set topo [new Topography]

$topo load_flatgrid 1000 1000  # 1km x 1km area

# Create the General Operations Director (GOD) for wireless simulations

create-god 3  # Number of nodes (3 optical nodes)

# Configure the nodes for optical communication

$ns node-config -llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 50 \

-antType Antenna/OmniAntenna \

-propType Propagation/FreeSpace \

-phyType Phy/WirelessPhy \

-channelType Channel/WirelessChannel \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace OFF

# Open trace and NAM files for recording the simulation

set tracefile [open optical_net_out.tr w]

$ns trace-all $tracefile

set namfile [open optical_net_out.nam w]

$ns namtrace-all-wireless $namfile 1000 1000

# Define a finish procedure to close files and end the simulation

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam optical_net_out.nam &

exit 0

}

# Create optical nodes

set node0 [$ns node]

set node1 [$ns node]

set node2 [$ns node]

# Set initial positions for optical nodes

$node0 set X_ 100.0

$node0 set Y_ 500.0

$node0 set Z_ 0.0

$node1 set X_ 500.0

$node1 set Y_ 500.0

$node1 set Z_ 0.0

$node2 set X_ 900.0

$node2 set Y_ 500.0

$node2 set Z_ 0.0

# Define high-speed optical links between nodes

$ns duplex-link $node0 $node1 10Gb 1ms DropTail  # 10 Gbps link with 1ms delay

$ns duplex-link $node1 $node2 10Gb 1ms DropTail  # 10 Gbps link with 1ms delay

# Introduce an error model to simulate optical link impairments

set loss_module [new ErrorModel]

$loss_module unit pkt

$loss_module set rate_ 0.001  # 0.1% packet loss rate to simulate optical impairments

$ns lossmodel $loss_module $node0 $node1

$ns lossmodel $loss_module $node1 $node2

# Define traffic from node0 to node2 through node1 (simulating optical communication)

set tcp [new Agent/TCP]

$ns attach-agent $node0 $tcp

set sink [new Agent/TCPSink]

$ns attach-agent $node2 $sink

$ns connect $tcp $sink

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ftp start

# Schedule the end of the simulation

$ns at 20.0 “finish”

# Run the simulation

$ns run

Step 3: Run the Tcl Script

Save the script with a .tcl extension, for instance, optical_net_simulation.tcl. At that time, execute the script using the following command in terminal:

ns optical_net_simulation.tcl

Step 4: Visualize the Simulation

To visualize the simulation, open the generated NAM file using:

nam optical_net_out.nam

Script Explanation

  • Optical Nodes: The nodes node0, node1, and node2 denotes an optical routers or switches in the network.
  • Optical Links: The duplex links among the nodes are configured with a data rate of 10 Gbps and a delay of 1 ms, that emulates the high-speed optical fiber connections.
  • Error Model: An error model with a 0.1% packet loss rate is established to replicate the deficiencies that might occur in an optical link, like attenuation or dispersion.
  • Traffic Generation: TCP traffic is produced from node0 to node2 through node1 that replicates data transmission over the optical network.

Customization

  • Wavelength-Division Multiplexing (WDM): To mimic WDM by describing multiple parallel links among the nodes that each denotes a different wavelength.
  • Advanced Routing Protocols: Execute or emulate the optical-specific routing protocols for dynamic wavelength assignment and routing in an optical network.
  • Optical Amplifiers and Regenerators: To mimic the optical amplifiers or regenerators by attaching the additional nodes that simply reroutes the signals without significant processing.
  • Multiple Traffic Types: validate with different kinds of traffic like VoIP, video streaming to emulate the various QoS requirements in the optical network.

Overall, here we learn about how to implement and process the optical network that performs in ns2 tool and also we see the sample snippets clearly. We also provide all kinds of information related optical network communication. If you need more help, just reach out to us at ns2project.com. We’re here to help you with network analysis for your Optical Network project in ns2tool and share the best outcomes with you.