To simulate Wide Area Networks (WANs) using NS2 has needs to design a network which extents a large geographical area, usually associates to multiple local area networks (LANs), data centres, or other network segments. In a WAN simulation, we can usually contain routers, links with different bandwidths and latency (to reflect real-world WAN features), and a variety of traffic types. WAN simulations can be utilized to learn network performance, routing protocols, congestion control, and Quality of Service (QoS) mechanisms.
Here is a step-by-step guide to simulate Wide Area Networks (WANs) using NS2:
Steps to Simulate Wide Area Networks Using NS2
- Install NS2:
Make sure that NS2 is installed on system. We can download it from the NS2 official website.
- Define WAN Topology:
A WAN usually consists of multiple routers, each denotes a network segment or geographic location, associated by high-latency and high-bandwidth links. We can describe multiple routers and set up links with diverse bandwidths and latency.
Example of defining a basic WAN topology:
set ns [new Simulator]
# Create nodes representing routers
set router1 [$ns node]
set router2 [$ns node]
set router3 [$ns node]
set router4 [$ns node]
# Define links between routers with different bandwidths and delays
$ns duplex-link $router1 $router2 10Mb 50ms DropTail
$ns duplex-link $router2 $router3 5Mb 100ms DropTail
$ns duplex-link $router3 $router4 20Mb 30ms DropTail
- Bandwidth: Set different link capacities, e.g., 10Mb (megabits per second), 5Mb, or 20Mb, to reflect changing the WAN speeds.
- Delay: WAN links usually have higher delays (e.g., 50ms to 100ms), that can be adapted for different link types.
- Add End Devices (Clients and Servers):
WANs usually associate clients and servers across different geographic locations. We can incorporate end devices like clients (sending requests) and servers (responding to those requests).
Example of adding clients and servers:
# Create client and server nodes
set client1 [$ns node]
set client2 [$ns node]
set server1 [$ns node]
set server2 [$ns node]
# Connect clients and servers to routers
$ns duplex-link $client1 $router1 100Mb 10ms DropTail
$ns duplex-link $client2 $router2 100Mb 10ms DropTail
$ns duplex-link $server1 $router3 100Mb 10ms DropTail
$ns duplex-link $server2 $router4 100Mb 10ms DropTail
In this example, two clients are associated to different routers, and two servers are linked to different routers.
- Configure Routing:
In a WAN simulation, routers manage the routing of packets among clients and servers. NS2 supports both static routing and dynamic routing protocols like OSPF (Open Shortest Path First) or BGP (Border Gateway Protocol). By default, NS2 utilizes the dynamic routing.
Example of enabling dynamic routing:
# Enable dynamic routing in NS2
$ns rtproto DV
In this case, DV (Distance Vector) routing is enabled however we can also execute custom routing protocols or replicate OSPF, BGP, or MPLS (Multiprotocol Label Switching) for more complex routing environment.
- Simulate Traffic (CBR, FTP, or HTTP):
WAN simulations usually contain to replicate different kinds of traffic, like CBR (Constant Bit Rate) for video streaming, FTP for file transfer, or HTTP traffic for web browsing. These traffic types can be utilized to replicate real-world WAN environment in which clients request services from remote servers.
Example of generating FTP traffic between a client and a server:
# Use TCP agents for reliable data transfer between client1 and server1
set tcp1 [new Agent/TCP]
set sink1 [new Agent/TCPSink]
$ns attach-agent $client1 $tcp1
$ns attach-agent $server1 $sink1
$ns connect $tcp1 $sink1
# Simulate FTP file transfer
set ftp1 [new Application/FTP]
$ftp1 attach-agent $tcp1
We can adapt the packet size and transmission rate for different traffic types to replicate changing loads in the WAN.
- Implement Congestion Control (Optional):
In WANs, congestion can happens because of high data rates or limited bandwidth. We can simulate congestion and implement TCP congestion control algorithms such as Reno, Tahoe, or NewReno to learn on how they manage congestion in the network.
Example of using TCP Reno for congestion control:
# Set TCP congestion control algorithm to Reno
Agent/TCP set class_ Reno
This sets TCP Reno as the congestion control techniques for all TCP traffic in the simulation.
- Implement QoS Mechanisms (Optional):
Quality of Service (QoS) mechanisms makes sure that high-priority traffic (like video or voice) gets preferential treatment in a WAN. We can mimic a QoS using priority queues, fair queuing, or Weighted Fair Queuing (WFQ).
Example of configuring priority queuing for different traffic types:
# Configure priority queues to prioritize certain traffic types
Queue/PriQueue set limit_ 50
Using the above procedures we completely get an advanced knowledge about the configuration setup and evaluation process to simulate the Wide Area Networks using ns2 tool. We will plan to deliver more information regarding the wide area network.
For best Wide Area Networks simulation, you must send us all your Research details we will give you immediate response with brief explanation. get guidance on network performance, routing protocols, congestion control, and Quality of Service (QoS) mechanisms from our leading technical experts.
