How to Implement Network Function Virtualization in ns2

To implement the Network Function Virtualization (NFV) within ns2 (Network Simulator 2) is difficult for the reason that ns2 is an older simulator mainly created for traditional networking protocols and it does not natively support recent concepts such as NFV. But, we can estimated the concept of NFV by mimicking main facets like the decoupling of network functions from physical hardware, dynamic resource allocation, and the chaining of network functions.

Step-by-Step Implementations:

Conceptual Overview

In an NFV scenario:

  1. Virtual Network Functions (VNFs): VNFs are software-based functions like firewalls, load balancers that run on general-purpose hardware rather than devoted devices.
  2. NFV Infrastructure (NFVI): It is contains the physical and simulated resources like compute, storage, networking on which the VNFs run.
  3. VNF Chaining: The procedure of chaining VNFs to make a service, in which the traffic passes over several VNFs in a particular order.

Step 1: Conceptualize the NFV Simulation

For this emulation, we will make a set-up in which numerous VNFs are chained together to make a network service. We will be mimicked VNFs as various nodes acting exact functions, and the chaining will be signified by routing traffic via these nodes.

Step 2: Create the Tcl Script

The following is an instance Tcl script that mimics a simple NFV scenario in ns2.

Example Tcl Script for Simulating NFV in ns2

# Create a simulator object

set ns [new Simulator]

# Define the topography object (for a moderate area)

set topo [new Topography]

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

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

create-god 6  # Number of nodes (1 source, 1 destination, 3 VNFs, 1 NFVI)

# Configure the nodes for the NFV scenario

$ns node-config -llType LL \

-macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue \

-ifqLen 50 \

-antType Antenna/OmniAntenna \

-propType Propagation/TwoRayGround \

-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 nfv_out.tr w]

$ns trace-all $tracefile

set namfile [open nfv_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 nfv_out.nam &

exit 0

}

# Create the NFVI node (where VNFs run)

set nfvi [$ns node]

# Create VNF nodes (e.g., firewall, load balancer, IDS)

set vnf1 [$ns node]

set vnf2 [$ns node]

set vnf3 [$ns node]

# Create source and destination nodes

set source [$ns node]

set destination [$ns node]

# Set initial positions for the nodes

$nfvi set X_ 500.0

$nfvi set Y_ 500.0

$nfvi set Z_ 0.0

$vnf1 set X_ 300.0

$vnf1 set Y_ 300.0

$vnf1 set Z_ 0.0

$vnf2 set X_ 500.0

$vnf2 set Y_ 300.0

$vnf2 set Z_ 0.0

$vnf3 set X_ 700.0

$vnf3 set Y_ 300.0

$vnf3 set Z_ 0.0

$source set X_ 100.0

$source set Y_ 500.0

$source set Z_ 0.0

$destination set X_ 900.0

$destination set Y_ 500.0

$destination set Z_ 0.0

# Define a custom procedure for simulating NFV service chaining

proc send_nfv_data {src dst packetSize rate} {

global ns

# Create a UDP agent to simulate data traffic

set udp [new Agent/UDP]

$ns attach-agent $src $udp

set null [new Agent/Null]

$ns attach-agent $dst $null

$ns connect $udp $null

# Generate data traffic using a CBR application

set cbr [new Application/Traffic/CBR]

$cbr attach-agent $udp

$cbr set packetSize_ $packetSize

$cbr set rate_ $rate

$cbr start

}

# Define the routing for the NFV service chain

$ns rtproto DV

# Set up the routing to pass through VNFs

$ns at 1.0 “$source setdest 300.0 300.0 5.0”

$ns at 2.0 “$vnf1 setdest 500.0 300.0 5.0”

$ns at 3.0 “$vnf2 setdest 700.0 300.0 5.0”

$ns at 4.0 “$vnf3 setdest 900.0 500.0 5.0”

# Simulate data transmission from source to destination through the VNFs

$ns at 5.0 “send_nfv_data $source $vnf1 512 100Kb”

$ns at 6.0 “send_nfv_data $vnf1 $vnf2 512 100Kb”

$ns at 7.0 “send_nfv_data $vnf2 $vnf3 512 100Kb”

$ns at 8.0 “send_nfv_data $vnf3 $destination 512 100Kb”

# Schedule the end of the simulation

$ns at 20.0 “finish”

# Run the simulation

$ns run

Step 3: Run the Tcl Script

We can save the script with a .tcl extension, for instance, nfv_simulation.tcl. Afterwards, we can run the script using the below command in the terminal:

ns nfv_simulation.tcl

Step 4: Visualize the Simulation

We can visualize the simulation, open the created NAM file using:

nam nfv_out.nam

Script Explanation

  • NFVI Node: The nfvi node is denotes the setup in which the VNFs run. In reality, it can be a server or a cluster of servers.
  • VNF Nodes: The nodes vnf1, vnf2, and vnf3 are signify various simulated network functions like firewall, load balancer, IDS that are portion of the service chain.
  • Source and Destination Nodes: The source and end nodes are denote the initial and final points of the traffic flow, passing over the VNFs.
  • Service Chaining: The script sets up routing to traffic passes via the VNF nodes in a particular order, mimicking an NFV service chain.

The topic was addressed through an orderly process, implemented and assessed with the help of the simulation tool ns2. Additional details will be presented regarding Network function virtualization as needed.

For optimal assistance and implementation guidance in Network Function Virtualization using ns2, please reach out to ns2project.com to achieve the best outcomes. We specialize in various networking protocols pertinent to your projects. Kindly provide us with the details of your project, and we will offer you the most effective guidance.