To simulate Multiprotocol Label Switching (MPLS) projects using NS2 has includes configuring the MPLS functionality that is not directly supported in typical NS2. MPLS is a approach utilized to accelerate network traffic flow by allocating labels to data packets. These labels permit routers (also known as Label Switch Routers, LSRs) to make forwarding decisions according to the label instead of looking up the IP address. MPLS supports numerous routing protocols and can be utilized to execute traffic engineering, VPNs, and QoS mechanisms.
There are MPLS extensions available for NS2, like MPLS-Linux or patches that incorporate MPLS functionality to NS2. These patches expand the NS2 to manage MPLS-specific features such as Label Distribution Protocol (LDP), Label-Switched Paths (LSPs), and traffic engineering.
Here’s a detailed step-by-step guide to simulate MPLS projects using NS2:
Steps to Simulate Multiprotocol Label Switching Projects in NS2
- Install NS2 and MPLS Patch
NS2 does not support MPLS by default, so we need to patch it to incorporate MPLS functionality. Follow these steps:
- Install NS2: Ensure ns2 is installed on the system.
- Download the MPLS Patch: we can identify MPLS extensions or patches like MPLS-Linux for NS2.
- Patch NS2: implement the MPLS patch to NS2 installation. Navigate to NS2 directory and implement the patch:
patch -p1 < mpls_ns2_patch.diff
- Rebuild NS2: After patching, rebuild NS2 to contain MPLS functionality:
make clean
make
- Understanding MPLS Components
MPLS has includes numerous components that will design in the simulation:
- Label Edge Routers (LERs): Routers that are responsible for place in (ingress) and take out (egress) MPLS labels.
- Label Switch Routers (LSRs): Intermediate routers that forward packets according to their labels.
- Label Switched Paths (LSPs): Predefined paths which MPLS traffic flows through.
- Label Distribution Protocol (LDP): Protocol utilized to introduce and maintain LSPs.
- TCL Script Structure for MPLS Simulation
Here is a simple instance of a TCL script to replicate MPLS using NS2. This script models a simple MPLS network with ingress and way out LERs and LSRs among them.
Example TCL Script for MPLS Simulation
# Create a simulator object
set ns [new Simulator]
# Open files for tracing and NAM visualization
set tracefile [open mpls.tr w]
$ns trace-all $tracefile
set namfile [open mpls.nam w]
$ns namtrace-all $namfile
# Define network topology
set topo [new Topography]
$topo load_flatgrid 1000 1000
# Define the link bandwidth, delay, and queue type
set bw 10Mb
set delay 10ms
set queue DropTail
# Create MPLS nodes (LERs and LSRs)
set LER1 [$ns node]
set LSR1 [$ns node]
set LSR2 [$ns node]
set LER2 [$ns node]
# Define link between nodes (LER1 <-> LSR1 <-> LSR2 <-> LER2)
$ns duplex-link $LER1 $LSR1 $bw $delay $queue
$ns duplex-link $LSR1 $LSR2 $bw $delay $queue
$ns duplex-link $LSR2 $LER2 $bw $delay $queue
# Set MPLS routing protocol
$ns node-config -mplsRouting MPLS
# Define MPLS agent for each node
set ingress_ler [new Agent/MPLS]
set intermediate_lsr1 [new Agent/MPLS]
set intermediate_lsr2 [new Agent/MPLS]
set egress_ler [new Agent/MPLS]
# Attach MPLS agents to the respective nodes
$ns attach-agent $LER1 $ingress_ler
$ns attach-agent $LSR1 $intermediate_lsr1
$ns attach-agent $LSR2 $intermediate_lsr2
$ns attach-agent $LER2 $egress_ler
# Define TCP agents at LER1 (ingress) and LER2 (egress)
set tcp [new Agent/TCP]
$ns attach-agent $LER1 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $LER2 $sink
# Connect TCP agent and Sink (TCP traffic through MPLS path)
$ns connect $tcp $sink
# Create an FTP application over TCP
set ftp [new Application/FTP]
$ftp attach-agent $tcp
# Schedule the start and stop of FTP traffic
$ns at 1.0 “$ftp start”
$ns at 10.0 “$ftp stop”
# End simulation after 15 seconds
$ns at 15.0 “finish”
# Define the finish procedure
proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
exec nam mpls.nam &
exit 0
}
# Run the simulation
$ns run
- Explanation of the Script
- Simulator Setup: The script initiate by generating the simulator object and describing trace and NAM files for logging.
- Node Creation: Four nodes are created, denotes two Label Edge Routers (LERs) at the edge of the network and two Label Switch Routers (LSRs) in between. These nodes form the simple MPLS topology.
- MPLS Configuration: MPLS agents are attached to the LERs and LSRs, and the simulation is setting up to utilize MPLS routing.
- TCP Traffic: TCP traffic is created from the ingress LER (LER1) to the egress LER (LER2) through the intermediate LSRs, and FTP traffic is created on top of the TCP connection.
- MPLS Path: The MPLS path among LER1 and LER2 is defined using label-switched paths, and the data packets are forwarded according to MPLS labels instead of IP lookups.
- Simulation End: The simulation executes for 15 seconds, and the FTP traffic terminates after 10 seconds.
- Running the Simulation
Once we have written the TCL script (e.g., mpls_simulation.tcl), execute it using the following command in NS2:
ns mpls_simulation.tcl
This will execute the MPLS simulation, create trace files, and generate a NAM file for visualization.
- Analysing the Results
- NAM Visualization: Utilize NAM (Network Animator) to envision the network, packet flow, and MPLS behaviour. Open the generated .nam file:
nam mpls.nam
We should be able to see how MPLS labels are utilized to forward traffic via the LSRs, without needing IP lookups at each hop.
- Trace File Analysis: measure the .tr trace file to learn MPLS behaviour, traffic flow, packet delay, and routing updates.
- Extending the Simulation
We can expand the basic MPLS simulation to execute more complex environment like:
- Traffic Engineering: Implement load balancing by adapting the MPLS paths to enhance network resource usage.
- QoS (Quality of Service): Apply QoS policies to select certain kinds of traffic, like real-time voice or video over MPLS.
- VPNs (Virtual Private Networks): Utilize MPLS to replicate VPNs by describing virtual routing instances via the MPLS network.
- Dynamic Label Distribution: Execute LDP (Label Distribution Protocol) or RSVP-TE (Resource Reservation Protocol – Traffic Engineering) to enthusiastically introduce label-switched paths (LSPs) according to real-time network conditions.
- Performance Metrics for MPLS
We need to evaluate the following parameters to measure MPLS:
- Throughput: Evaluate the data transmission rate over the MPLS network.
- Latency/Delay: Assess the time it takes for packets to traverse the MPLS path from source to destination.
- Packet Loss: Evaluate on how many packets are lost in the course of transmission.
- Label Distribution Overhead: measure the overhead acquired by MPLS label distribution messages.
The above demonstration presented the simple approaches using the example coding snippets for multiprotocol label switching projects which were simulated and evaluated using ns2 tool. If needed, we provide more information regarding this process.
To explore the simulation of Multiprotocol Label Switching (MPLS) projects utilizing the NS2 framework, phdprime.com offers a dedicated team focused on executing these projects with the NS2 tool. We are also committed to sharing exemplary project ideas and topics within this domain. We invite you to send us your comprehensive details via email, and we will offer you optimal guidance. Our specialists will guarantee that the simulation and overall project performance meet the highest standards. Our work encompasses Label Distribution Protocol (LDP), Label-Switched Paths (LSPs), and traffic engineering.
