How to Start Link Aggregation Control Protocol Projects Using NS2

The Link Aggregation Control Protocol (LACP) is part of the IEEE 802.1AX standard like as formerly IEEE 802.3ad and is used to associate the several physical connection into a single logical link such as also known as a link aggregation group or LAG. LACP supports to enhance the bandwidth and offers the redundancy in network connections. In the context of NS2, replicating the LACP can be variation, as NS2 does not have a built-in apply the LACP. But, it is still possible to replicate examine the impact of LACP on network performance through representing its behavior manually.

In this tutorial, we will go through on how to replicate the Link Aggregation and implement LACP behavior in NS2 through associate the several connections among two nodes and replicating the failover and load balancing.

Steps to Start a Link Aggregation Control Protocol (LACP) Project in NS2

  1. Install NS2

If you have not previously installed NS2, we can do so using the following steps:

  • For Ubuntu/Debian:

sudo apt update

sudo apt install ns2

sudo apt install nam

  • For Windows: we may require a setting for Linux on a virtual machine or use Cygwin to install NS2.

To validate if NS2 is correctly installed, run:

ns

  1. Understand the Link Aggregation Control Protocol (LACP)
  • LACP operates with grouping several connections among the two devices into a single logical link. This enhanced a bandwidth and offers the redundancy.
  • The protocol used the control frames we negotiate the aggregation of different connection and determine that connections are active.
  • In case of connection failure, LACP dynamically regulates via removing the failed connection from the aggregation group.

In NS2, while LACP is not directly applied, we can replicate the following features for LACP:

  • Link aggregation with generating a various parallel connection among the two nodes.
  • Load balancing through allocate the congestion with the aggregated links.
  • Link failure replication to apply the failover behavior.
  1. Design the Network Topology

To replicate the LACP in NS2:

  • We will require two nodes for sample two routers or switches and different redundant links among them to signify the aggregated links.
  • We will also replicate the host-to-host traffic and follow on how the traffic is allocated with the aggregated connection.
  1. Simulate Link Aggregation in NS2

Since NS2 doesn’t natively helps LACP, we will create a network topology by several connection and replicate the load balancing and failover aspects.

Example TCL Script for LACP Simulation in NS2

# Create a simulator object

set ns [new Simulator]

# Create nodes: two routers and two hosts

set router1 [$ns node]

set router2 [$ns node]

set host1 [$ns node]

set host2 [$ns node]

# Create multiple links between the routers to simulate LACP

$ns duplex-link $router1 $router2 100Mb 10ms DropTail

$ns duplex-link $router1 $router2 100Mb 10ms DropTail

$ns duplex-link $router1 $router2 100Mb 10ms DropTail

# Create links from routers to hosts

$ns duplex-link $router1 $host1 10Mb 20ms DropTail

$ns duplex-link $router2 $host2 10Mb 20ms DropTail

# Define traffic: CBR (Constant Bit Rate) between host1 and host2

set udp1 [new Agent/UDP]

set sink1 [new Agent/Null]

$sink1 attach-agent $host2

$udp1 attach-agent $host1

set cbr1 [new Application/Traffic/CBR]

$cbr1 set packetSize_ 512

$cbr1 set interval_ 0.1

$cbr1 attach-agent $udp1

$ns connect $udp1 $sink1

# Traffic starts at 1.0s and stops at 5.0s

$ns at 1.0 “$cbr1 start”

$ns at 5.0 “$cbr1 stop”

# Enable tracing

$ns trace-all “lacp_output.tr”

$ns namtrace-all “lacp_output.nam”

# Run the simulation

$ns run

  1. Explanation of the Script
  1. Node Creation:
    • The script initializes through generating the two routers such as router1 and router2 and two hosts for instance host1 and host2.
    • Every router and host is made using by the $ns node.
  2. Link Creation:
    • Multiple links for sample 3 in this case are generated among the router1 and router2 we replicate the connection for aggregation. The duplex links are made with a bandwidth of 100Mb and delay of 10ms.
    • A single link is created among the routers and hosts such as host1 and host2 we replicate the link from the router to the hosts.
  3. Traffic Generation:
    • CBR (Constant Bit Rate) are congestion is setting among the host1 and host2 we replicate the network congestion.
    • The CBR starts at 1 second and stops at 5 seconds.
  4. Tracing:
    • Trace and NAM files are created using $ns trace-all and $ns namtrace-all for complete packet-level examine and network animation.
    • These files can be used to examine on how the traffic is allocate with the different connection.
  5. Running the Simulation:
    • The script ends through $ns run, that process for the replication.
  1. Simulating Link Failures and Failover

We replicate the failover behavior of LACP; we can establish the link failures and follow on how the traffic is rerouted over the remaining connection.

Here is how to add link failure simulation:

# Introduce a failure in one of the links between the routers

$ns at 2.0 “$ns down $router1 $router2”  ;# This simulates a link failure at 2 seconds

 

# After 1 second, bring up the failed link again

$ns at 4.0 “$ns up $router1 $router2”    ;# This simulates the link coming back up at 4 seconds

This replicates the link failure and restoration after a set of period that is a typical environment in LACP-enabled networks. The congestion will before be the rerouted with the remaining active connection until the failed connection is restored.

  1. Run and Analyze the Results

Next process for the replication we can examine the outcomes:

  1. NAM Visualization:
    • The NAM tool can be used to envision the network:

nam lacp_output.nam

    • In NAM, we will view the network topology; have including the routers, hosts, and connection. You can follow on how the traffic flows with several links on how the system response after a connection fails and recovers.
  2. Trace File Analysis:
    • The trace file for sample lacp_output.tr has contained the complete information about the packet flow, involves the how on packets is routed with the several connection.
    • We can use awk or other tools we examine the trace file:

awk ‘{print $1, $2, $3, $4}’ lacp_output.tr

  1. Extend the Project

You can extend the LACP simulation in several ways:

  • Increase the number of links: Enhance the further connection among the routers to replicate a larger connection aggregation.
  • Test different traffic types: Used validate other kinds of congestion such as FTP, HTTP, or VoIP we examine the behavior of connection aggregate to below various loads.
  • Simulate more complex failures: several connection are fail to replicate at the various times and monitor on how the system adapts.
  • Advanced Load Balancing: Apply the simple load balancing technique to allocate the congestion with several connections according to the load or round-robin methods.

With this configuration, we can exhaustively make you understand the implementation steps of offered example regarding Link Aggregation using ns2 simulator tools. For further queries concerning this manual, we will resolve it over another manual