How to Implement Video Traffic Scheduling in NS2

To implement video traffic scheduling in NS2 has needs to mimic video traffic over a network and utilizing a scheduling mechanism to choose and handle how the video data packets are routed. In real-world scenarios, video traffic needs high throughput, low latency, and minimal packet loss to make sure smooth playback. To replicate this in NS2, we can create video traffic using UDP or TCP and execute a queue scheduling mechanism to select video packets over other traffic. Keep in contact with ns2project.com as we continue to analyze network performance and execute your video traffic scheduling projects.

Below is the guide on how to implement video traffic scheduling in NS2:

Steps to Implement Video Traffic Scheduling:

  1. Generate video traffic using UDP to mimic real-time video streaming.
  2. Implement scheduling to select video packets in other types of traffic.
  3. Use a priority queue (PriQueue) to handle the packet scheduling.
  1. NS2 Setup for Video Traffic

Initially, configure the NS2 environment with nodes and describe a wireless or wired channel for communication. We will simulate video traffic among two nodes.

# Create an NS2 simulator instance

set ns [new Simulator]

# Open trace files for logging the simulation

set tracefile [open “video_traffic_scheduling.tr” w]

set namfile [open “video_traffic_scheduling.nam” w]

$ns trace-all $tracefile

$ns namtrace-all-wireless $namfile 500 500

# Define the wired channel or wireless channel for communication

set chan_1_ [new Channel/WirelessChannel]

# Define a topography for wireless communication

set topo [new Topography]

$topo load_flatgrid 500 500

# Define propagation, MAC, queue, and antenna parameters

set prop [new Propagation/TwoRayGround]   ;# Propagation model

set netif [new Phy/WirelessPhy]           ;# Wireless physical layer

set mac [new Mac/802_11]                  ;# MAC protocol

set ll [new LL]                           ;# Link layer

set ifq [new Queue/DropTail/PriQueue]     ;# Priority Queue for traffic scheduling

set ant [new Antenna/OmniAntenna]

# Configure node parameters

$ns node-config -llType $ll \

-macType $mac \

-ifqType $ifq \

-ifqLen 50 \              ;# Queue length for packet management

-antType $ant \

-propType $prop \

-phyType $netif \

-channel $chan_1_ \

-topoInstance $topo

  1. Creating Nodes and Setting up Video Traffic

Describe nodes that will create video traffic. We will replicate video traffic as UDP traffic that denotes a continuous video stream.

Example: Setting up Video Traffic between Two Nodes

# Define two nodes: sender (source) and receiver (destination)

set sender [$ns node]

set receiver [$ns node]

# Position the nodes

$sender set X_ 100

$sender set Y_ 200

$receiver set X_ 300

$receiver set Y_ 300

# Create a UDP agent for video traffic at the sender

set udp_video [new Agent/UDP]

set null_sink [new Agent/Null]

# Attach agents to the sender and receiver nodes

$ns attach-agent $sender $udp_video

$ns attach-agent $receiver $null_sink

# Connect the UDP agent on the sender to the null agent on the receiver

$ns connect $udp_video $null_sink

# Create CBR traffic to simulate continuous video stream

set video_stream [new Application/Traffic/CBR]

$video_stream attach-agent $udp_video

$video_stream set packetSize_ 1000      ;# Set packet size for video traffic

$video_stream set rate_ 1Mb             ;# Set rate for video traffic

# Start and stop the video stream at specific times

$ns at 1.0 “$video_stream start”

$ns at 20.0 “$video_stream stop”

  1. Implementing Scheduling with PriQueue

To execute traffic scheduling, use priority queues (PriQueue). PriQueue in NS2 enable diverse classes of traffic to be allocated different priorities, with higher-priority traffic such as video being communicated before lower-priority traffic like background or best-effort traffic.

We can allocate a higher priority to video traffic so that the network selects video packets over other types of data.

Example: Setting Priorities for Video Traffic

# Assign high priority to the UDP video traffic agent

$udp_video set prio_ 1   ;# Assign the highest priority (1) to video traffic

We can further configure other types of traffic such as background traffic with lower priority levels.

  1. Generating Background Traffic (Lower Priority)

To monitor on how the scheduling works, creates background traffic that has a lower priority than the video traffic. This traffic will contend for bandwidth, however since video traffic has higher priority, it will be scheduled first.

Example: Setting up Background Traffic (Lower Priority)

# Create a TCP agent for background traffic

set tcp_bg [new Agent/TCP]

set tcp_sink [new Agent/TCPSink]

# Attach TCP agents to sender and receiver

$ns attach-agent $sender $tcp_bg

$ns attach-agent $receiver $tcp_sink

# Connect TCP agent to TCPSink (background traffic)

$ns connect $tcp_bg $tcp_sink

# Create FTP traffic over TCP to simulate background data transfer

set ftp_bg [new Application/FTP]

$ftp_bg attach-agent $tcp_bg

# Assign lower priority to background traffic

$tcp_bg set prio_ 2  ;# Set lower priority (2) for background traffic

# Start and stop the background FTP traffic

$ns at 2.0 “$ftp_bg start”

$ns at 18.0 “$ftp_bg stop”

  1. Running the Simulation

Describe the simulation duration and run it.

# Set the simulation end time

$ns at 25.0 “finish”

# Finish procedure to close trace files and end simulation

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exit 0

}

# Run the simulation

$ns run

  1. Analysing the Results

After executing the simulation, we can evaluate the trace files and network animation (NAM) to assess the performance of video traffic scheduling:

  • Throughput: validate if video traffic achieves the essential throughput.
  • Latency: Assess the delay experienced by video packets.
  • Packet Loss: Regulate if any video packets were dropped because of network congestion.
  • Background Traffic Behavior: Validate that lower-priority traffic is routed after higher-priority video traffic.
  1. Optimizing Scheduling for Video Traffic

To enhance video traffic further:

  • Use different scheduling policies in the queue if NS2 supports them.
  • Tune the queue size and buffer management to selects real-time video traffic.
  • Validate with diverse traffic patterns (such as variable bit rate (VBR)) to design more realistic video traffic.

We clearly share the information about how to implement and visualize the results for video traffic scheduling that is used to schedule and manage the routes in the traffic that were executed using the ns2 simulation tool.  Additional specific details regarding the video traffic scheduling will also be providing.