How to Implement Network Telepresence in NS2

To implement Telepresence in ns2 has a series of steps that follows and it is defined to technologies that permit individuals to feel or perform as if they are present in a location they are not physically in. It can be understood as a cutting-edge form of video conferencing with the addition of high-definition video, audio, and usually a communication via robotic systems.

To mimic network telepresence in NS2 that is essential to mimic high-bandwidth, real-time traffic for video and audio, and optionally that contain control signals if mimicking robotic communication. If you need help with any kind of implementation, just reach out to us! We’re here to give you the best results possible.

Here is a procedure to mimic a simple telepresence system in NS2:

Steps for Implementing Telepresence in NS2:

  1. Network Setup: We need to describe the nodes in the network that denotes the telepresence participants such as the remote participant and the local participant and introduce the communication links among them.
  2. Simulating High-Definition Video and Audio: We can replicate the video and audio streams separately, alike to how to execute a video conference, however with higher quality (higher bandwidth) and potentially lower latency to mimic real-time communication.
  3. Simulating Control Signals (Optional): If the telepresence setup contains robotic controls, that can replicate low-latency control signals using additional UDP flows or traffic generators to denotes the control commands being sent among the nodes.

Example Tcl Script for Telepresence Simulation:

# Create a new simulator instance

set ns [new Simulator]

# Define output trace file for analysis

set tracefile [open telepresence.tr w]

$ns trace-all $tracefile

# Define animation file for NAM visualization

set namfile [open telepresence.nam w]

$ns namtrace-all $namfile

# Create nodes (representing telepresence participants)

set n0 [$ns node]  # Remote participant

set n1 [$ns node]  # Local participant

# Create a duplex link between the nodes with high bandwidth and low delay

$ns duplex-link $n0 $n1 100Mb 10ms DropTail

# Define UDP agents for high-quality video stream

set udp_video [new Agent/UDP]

$ns attach-agent $n0 $udp_video

set udp_video_sink [new Agent/Null]

$ns attach-agent $n1 $udp_video_sink

# Connect the UDP video agents

$ns connect $udp_video $udp_video_sink

# Define video traffic generator for telepresence

set videoTraffic [new Application/Traffic/CBR]

$videoTraffic attach-agent $udp_video

# High-definition video parameters

$videoTraffic set packetSize_ 1500      # Larger packets for HD video

$videoTraffic set rate_ 5Mb             # High-quality video bitrate

$videoTraffic set interval_ 0.033       # Frame rate of 30 frames per second

# Start the video stream

$ns at 0.5 “$videoTraffic start”

# Define UDP agents for audio stream

set udp_audio [new Agent/UDP]

$ns attach-agent $n0 $udp_audio

set udp_audio_sink [new Agent/Null]

$ns attach-agent $n1 $udp_audio_sink

# Connect the UDP audio agents

$ns connect $udp_audio $udp_audio_sink

# Define audio traffic generator for telepresence

set audioTraffic [new Application/Traffic/CBR]

$audioTraffic attach-agent $udp_audio

# Audio parameters (smaller packet size and lower bitrate)

$audioTraffic set packetSize_ 256        # Audio packet size

$audioTraffic set rate_ 128Kb            # Audio bitrate

$audioTraffic set interval_ 0.02         # Simulating real-time audio

# Start the audio stream

$ns at 0.5 “$audioTraffic start”

# Optional: Define UDP agents for control signals (robotic or interaction commands)

set udp_control [new Agent/UDP]

$ns attach-agent $n0 $udp_control

set udp_control_sink [new Agent/Null]

$ns attach-agent $n1 $udp_control_sink

# Connect the control agents

$ns connect $udp_control $udp_control_sink

# Define control traffic generator (low latency control signals)

set controlTraffic [new Application/Traffic/CBR]

$controlTraffic attach-agent $udp_control

# Control signals: small packets, very low latency

$controlTraffic set packetSize_ 64       # Control packet size

$controlTraffic set rate_ 32Kb           # Low bandwidth for control commands

$controlTraffic set interval_ 0.01       # Very frequent control commands

# Start the control stream

$ns at 0.5 “$controlTraffic start”

# Schedule the simulation to end

$ns at 10.0 “finish”

# Define a finish procedure

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam telepresence.nam &

exit 0

}

# Run the simulation

$ns run

Explanation of the Script:

  1. Node Setup:
    • n0 and n1 denotes the remote participant and local participant, correspondingly.
    • The duplex link among them has high bandwidth (100Mb) and low delay (10ms) to mimic a fast, reliable network connection that is essential for telepresence.
  2. Video Traffic:
    • Video traffic is replicated using UDP, as real-time applications usually prefer UDP for low latency.
    • The CBR (Constant Bit Rate) traffic generator mimics a high-definition video stream with a packet size of 1500 bytes (typical for video), a rate of 5Mb, and an interval of 0.033 seconds to denote 30 frames per second.
  3. Audio Traffic:
    • Audio traffic is also mimicked using UDP but with lower bandwidth and smaller packet sizes.
    • The packetSize_ is set to 256 bytes, and the bitrate is set to 128Kb to mimic typical audio traffic for a telepresence system.
  4. Control Traffic (Optional):
    • If the telepresence system has contained remote robotic control or real-time communication, this can be mimicked with small, frequent packets using UDP.
    • Control traffic is created using small packets (64 bytes) and a low bitrate (32Kb), with frequent transmission intervals to mimic low-latency control commands.
  5. Simulation Schedule:
    • The traffic for video, audio and control streams all initiate at 0.5 seconds and endure until the simulation terminate at 10 seconds.
  6. Finish Procedure:
    • At the end of the simulation, trace and NAM files are closed, and the NAM envisions is launched systematically.
  1. Running the Simulation

Save the Tcl script as telepresence_simulation.tcl and execute it in NS2:

ns telepresence_simulation.tcl

  1. Visualizing with NAM

We can envision the telepresence traffic in NAM by running:

nam telepresence.nam

This will demonstrate the traffic among the nodes, that denotes the high-definition video, audio, and control signal flows.

  1. Analysing the Output

The output trace file (telepresence.tr) will encompass information about packet transmission, reception, and loss. We can use this file to evaluate:

  • Throughput: Total data successfully routed.
  • Packet Loss: Critical for real-time applications such as telepresence, packet loss should be minimal.
  • Latency/Delay: assess the end-to-end delay that impacts the real-time experience.
  1. Enhancing the Simulation
  • Packet Loss Simulation: Establish packet loss using an NS2 error model to mimic how the telepresence system acts as in poor network conditions.
  • Congestion Simulation: Add other traffic types such as background traffic to mimic network congestion and its effects on telepresence performance.
  • Multi-Participant Telepresence: We can extend the script to contain multiple participants that is more nodes to replicate a multi-participant telepresence session.

From the demonstration we clearly learned the novel concepts that were sophisticated to implement the Telepresence in ns2 that outperforms the better results to manage the communication via robotic system. We plan to deliver more information regarding the Telepresence.