How to Start Temporally Ordered Routing Projects Using NS2

To start Temporally Ordered Routing (TOR) using NS2 which is a routing method that gives precedence to the order of events or actions according to the time. It is typically utilised within scenarios in which the data transmission timing performs as an essential role within real-time applications like voice over IP, video conferencing, or live streaming. TOR protocols target is making sure that packets reach in the exact sequence and in time constraints that is specifically crucial within time-sensitive applications.

To execute the Temporally Ordered Routing which normally has creation of routing algorithms that represent time-sensitive factors like delay, scheduling, and ordering of packets in NS2. NS2 doesn’t directly support a built-in temporally ordered routing protocol, but we can be replicated behavior by means of creating the simulation configuration, managing packet scheduling, and making sure time-based delivery restrictions.

Below is a stepwise technique to get started with a Temporally Ordered Routing project in NS2:

Steps to Start Temporally Ordered Routing Projects in NS2

  1. Install NS2
  • We adhere to installation steps to install NS2, if is not installed earlier.
  • For Linux (Ubuntu/Debian-based):

sudo apt update

sudo apt install ns2

sudo apt install nam

  • For Windows: We can utilise a virtual machine or Cygwin, since NS2 does not directly support Windows.

After installing, we confirm the installation:

ns

It would go to the NS2 command-line interface.

  1. Understand Temporally Ordered Routing

In TOR, the aim is to make that:

  • Packets are delivered in the correct order: The system have to sustain the packets sequence since they were created by the sender.
  • Time constraints: Packets will be distributed in specific time limits like low latency, jitter control, making sure that better user experience that particularly in real-time applications.

For example, packets want to attain on the receiver within the exact order and with minimal delay in a video streaming application, to make sure that video frames are shown within the correct sequence and devoid of noticeable delay.

Below is an essential concepts:

  • Time-sensitive delivery: Make sure packets are distributed in a provided time window.
  • Packet scheduling: Packets would send within a correct method, which follows temporal order that may want to manage the transmission schedule.
  • Priority and Quality of Service (QoS): The routing protocol may give precedence to traffic depends on time-sensitive requirements.
  1. Set Up Your NS2 Simulation Environment

Following is simple steps for replicating Temporally Ordered Routing within NS2:

  1. Creating the network topology: Configure a network including nodes, links, and traffic sources.
  2. Defining time-sensitive traffic: Replicate the real-time applications such as video streaming or voice over IP (VoIP) including restrictions on timing.
  3. Control packet scheduling: Make sure that packets are transmitted and inherited to utilise event scheduler of NS2 in the proper manner and within time restrictions.

Example: Basic Setup with Temporally Ordered Routing

Below is an instance of how we can configure basic network including Temporally Ordered Routing to utilise CBR traffic (Constant Bit Rate), which mimics time-sensitive interaction using NS2.

# Create a simulator object

set ns [new Simulator]

# Create nodes (4 nodes: 1 source, 3 receivers)

set n0 [$ns node]  ;# Source node

set n1 [$ns node]  ;# Intermediate node

set n2 [$ns node]  ;# Receiver 1

set n3 [$ns node]  ;# Receiver 2

# Create links between nodes

$ns duplex-link $n0 $n1 10Mb 20ms DropTail

$ns duplex-link $n1 $n2 10Mb 20ms DropTail

$ns duplex-link $n1 $n3 10Mb 20ms DropTail

# Set up time-sensitive traffic (CBR for video or voice communication)

set cbr1 [new Application/Traffic/CBR]

$cbr1 set packetSize_ 512

$cbr1 set interval_ 0.05  ;# 20 packets per second, typical for audio/video

$cbr1 attach-agent $n0

# Define packet scheduling to maintain temporally ordered transmission

# Use Event Scheduling in NS2 to send packets at specific times

$ns at 1.0 “$cbr1 start” ;# Start sending at time 1.0 seconds

# Receiver nodes (n2 and n3) will receive the traffic

set sink1 [new Agent/Null]

$sink1 attach-agent $n2

set sink2 [new Agent/Null]

$sink2 attach-agent $n3

# Connect agents

$ns connect $cbr1 $sink1

$ns connect $cbr1 $sink2

# Run the simulation

$ns run

  1. Simulating Temporally Ordered Routing

In the above case, packets are transmitted from node n0 to n2 and n3 on a constant rate (CBR). The temporally ordered routing’s essential portion is making sure that packets are transmitted and inherited within proper sequence whereas concerning timing constraints.

  • Packet scheduling: We can manage the correct timing by utilising the event scheduler using NS2 like $ns at <time>, once packets are transmitted that is crucial for temporally ordered routing.
  • Priority traffic: If make sure that some packets contain higher priority then we can utilise the Priority Queueing or other QoS mechanisms available within NS2.

Example: Handling Packet Order

We need to make sure that packets are distributed within the proper manner by means of managing the packet flow. It can be done to sustain the exact temporal order of the traffic utilising mechanisms such as sequential timestamps or event-based scheduling.

For example, deliberate a basic approach of making sure that packet order with the help of timestamps:

# Send packets with time-based ordering using timestamps

set cbr1 [new Application/Traffic/CBR]

$cbr1 set packetSize_ 512

$cbr1 set interval_ 0.1  ;# 10 packets per second

$cbr1 attach-agent $n0

# Set timestamps for packet transmission

$ns at 0.0 “$cbr1 start”

$ns at 2.0 “$cbr1 stop” ;# Stop sending packets after 2.0 seconds

In this instance, the event scheduler makes sure that the packets are sent on certain times and in order.

  1. Define Time Constraints for Real-Time Applications

We need to describe the time limitations for packet delivery making sure that the packets are distributed in the delay restrictions required for time-sensitive applications such as real-time video or voice communication.

For example:

  • End-to-End Delay: Define an acceptable threshold for end-to-end delay.
  • Latency Sensitivity: Configure QoS metrics for managing latency-sensitive traffic.
  • Buffering/Queue Management: Minimize jitter and sustain the temporal order of packets to utilise traffic shaping or packet scheduling.

# Example of controlling end-to-end delay

set max_delay 100ms  ;# Set max delay for packet transmission

  1. Use Trace Files and NAM for Analysis

NS2 environment permits to make trace files that offer insights regarding packet events, delivery times, and the network overall performance. We can be utilised these trace files for examining how successfully Temporally Ordered Routing is functioning and whether packets are send in the necessary time constraints.

Enable Tracing:

# Enable trace for packet delivery and routing

$ns trace-all “output.tr”

During the simulation, it will be created a trace file (output.tr) including all the events.

Make use of NAM (Network Animator) to envision the simulation and then examining the packet delivery timing:

nam output.nam

  1. Test with Different Traffic Types

We can test with diverse traffic types to replicate various real-time applications:

  • CBR (Constant Bit Rate): It is optimal to replicate the voice or video interaction.
  • UDP: It mimics real-time interaction with no response which is helpful for time-sensitive applications.
  • RTP (Real-Time Protocol): It utilised in multimedia applications for sending audio and video.

# Example: Use RTP for video streaming

set rtp [new Application/Traffic/RTP]

$rtp set packetSize_ 512

$rtp set interval_ 0.1  ;# Set interval for video frames

$rtp attach-agent $n0

  1. Implement Custom Temporally Ordered Routing Protocols

In NS2, if we need exceed the simple packet scheduling then we can execute the custom temporally ordered routing protocols. It encompasses to change or prolong the existing routing protocols to represent temporal constraints like:

  • Custom event scheduling procedures, which apply packet delivery in certain time windows.
  • Traffic shaping methods give precedence to packets according to the time sensitivity.
  1. Enhancements and Extensions

We need to enhance and prolong the Temporally Ordered Routing configuration by means of integrating:

  • Node mobility: We can mimic mobility within time-sensitive networks to experiment how routing protocols adjust to dynamic environments.
  • Advanced QoS: Execute additional sophisticated Quality of Service (QoS) mechanism, making sure the time-sensitive packets delivery including less jitter and delay.
  • Multiple traffic types: Replicate several real-time traffic flows and manage the scheduling needs.

We can replicate and examine the networks in which packet timing and order are crucial through above sequential methodology using NS2 environment. Let me know, if you want more insights on this topic, we will be shared