To simulate an IEEE 802.1Q VLAN (Virtual LAN) Tagging projects utilizing NS2 that needs knowing how VLAN tagging works in real-world networking. VLANs permit for logical separation of networks on the similar physical infrastructure, allowing better network management, security, and scalability. The IEEE 802.1Q standard launches VLAN tagging that inserts an additional header to Ethernet frames to show VLAN membership.
The network simulator NS2 does not have native support for VLAN tagging, however we can be replicated the behaviour of VLANs by modelling VLANs as logical groupings of nodes, and changing the handling of packets according to their VLAN ID. It includes denoting VLAN-aware switches and replicating the flow of traffic via those switches even though make sure that packets only attain the suitable VLAN members.
Here’s a stepwise guide to simulate IEEE 802.1Q VLAN Tagging projects using NS2.
Steps to Simulate IEEE 802.1Q VLAN Tagging Using NS2
- Install NS2:
Make certain NS2 is installed and running on the system. We can download it from the NS2 official website. VLANs are not directly supported in NS2, thus we will want to replicate VLAN-like behaviour via node and link configurations.
- Define Network Topology with VLANs:
In a normal VLAN environment, several hosts are split into distinct VLANs. These hosts are connected to VLAN-aware switches that handle traffic rely on VLAN IDs. In NS2, we can denote it by logically grouping nodes into VLANs.
Example of defining a simple VLAN-based topology:
set ns [new Simulator]
# Create Ethernet nodes (hosts and VLAN-aware switch)
set host1 [$ns node]
set host2 [$ns node]
set host3 [$ns node]
set host4 [$ns node]
set switch1 [$ns node]
# Define duplex links between hosts and switch
$ns duplex-link $host1 $switch1 100Mb 1ms DropTail
$ns duplex-link $host2 $switch1 100Mb 1ms DropTail
$ns duplex-link $host3 $switch1 100Mb 1ms DropTail
$ns duplex-link $host4 $switch1 100Mb 1ms DropTail
In this topology:
- host1 and host2 will be part of VLAN 10.
- host3 and host4 will be part of VLAN 20.
- switch1 will mimic VLAN-aware behaviour.
- Simulate VLAN Tagging Behaviour:
In VLAN networks, traffic is isolated according to VLAN tags. Even though NS2 doesn’t natively support VLAN tagging, we can be replicated it by changing packet flows and ensuring traffic is separated based on the VLAN ID.
We can execute VLAN-like behaviour by verifying packet flows and limiting communication among the nodes, which do not belong to the similar VLAN.
Example of simulating VLAN isolation:
# Define VLAN IDs for each host
set vlan(1) 10 ;# VLAN 10 for host1
set vlan(2) 10 ;# VLAN 10 for host2
set vlan(3) 20 ;# VLAN 20 for host3
set vlan(4) 20 ;# VLAN 20 for host4
# Create a custom function to simulate VLAN tagging and filtering
proc vlanFilter { src dst } {
global vlan
if { $vlan($src) != $vlan($dst) } {
puts “VLAN Mismatch: Dropping packet between host $src and host $dst”
return 0 ;# Drop the packet
} else {
puts “VLAN Match: Forwarding packet between host $src and host $dst”
return 1 ;# Allow the packet
}
}
# Simulate traffic between hosts and apply VLAN filtering
set udp1 [new Agent/UDP]
set udp2 [new Agent/UDP]
$ns attach-agent $host1 $udp1
$ns attach-agent $host3 $udp2
$ns connect $udp1 $udp2
# Filter traffic based on VLAN
if { [vlanFilter 1 3] == 1 } {
puts “Allowing traffic between host1 and host3”
# Start traffic generation here
} else {
puts “Blocking traffic between host1 and host3”
}
In this example:
- The vlanFilter technique verifies whether the source and destination belong to the similar VLAN. If they don’t then the packet is dropped.
- It can mimic VLAN isolation behaviour in which traffic is restricted to devices within the similar VLAN.
- Simulate Communication Within VLANs:
We can generate traffic among the hosts, which are part of the same VLAN. It is where traffic flows without restrictions only if both hosts belong to the similar VLAN.
Example of generating traffic within a VLAN:
# Simulate UDP traffic between host1 and host2 (both in VLAN 10)
set udp1 [new Agent/UDP]
set null1 [new Agent/Null]
$ns attach-agent $host1 $udp1
$ns attach-agent $host2 $null1
$ns connect $udp1 $null1
set cbr1 [new Application/Traffic/CBR]
$cbr1 set packetSize_ 512
$cbr1 set interval_ 0.05 ;# Send one packet every 50ms
$cbr1 attach-agent $udp1
# Start the traffic flow
$ns at 1.0 “$cbr1 start”
Because host1 and host2 are part of the similar VLAN, the traffic will be permitted and flow without restrictions.
- Simulate VLAN Traffic Across Switches (Trunking):
In a more advanced VLAN scenario, traffic may pass among numerous switches. VLAN trunking (802.1Q) permits traffic from several VLANs to pass over a unique link among the switches. We can replicate this behaviour by make sure that VLAN tags are conserved and respected across switches.
Example of simulating a VLAN trunk between two switches:
set switch2 [$ns node]
# Define a trunk link between switch1 and switch2
$ns duplex-link $switch1 $switch2 1Gb 2ms DropTail
# Simulate traffic between hosts across switches
set udp3 [new Agent/UDP]
set null3 [new Agent/Null]
$ns attach-agent $host1 $udp3
$ns attach-agent $host4 $null3
$ns connect $udp3 $null3
# Apply VLAN filter to simulate trunk traffic
if { [vlanFilter 1 4] == 1 } {
puts “Allowing traffic across trunk between host1 and host4”
# Start traffic flow here
} else {
puts “Blocking traffic between host1 and host4”
}
In this instance, traffic among host1 and host4 will be blocked since they belong to distinct VLANs. The vlanFilter make sure that traffic crossing the trunk link is subject to VLAN membership checks.
- Run the Simulation:
When we have set up the VLAN topology and traffic then we can run the simulation using NS2.
Example of running the simulation:
ns vlan_simulation.tcl
We can envision the simulation using NAM (Network Animator) to monitor how VLAN traffic flows and is filtered:
nam vlan_simulation.nam
- Analyse Results:
After running the simulation we can investigate the network performance parameters like:
- Packet Delivery: Make certain that packets are only delivered to hosts in the same VLAN.
- Latency: Estimate the delay for traffic in VLANs and across switches.
- Packet Loss: Verify if any packets are dropped because of VLAN mismatch.
We can be used AWK or Python scripts to examine the trace file (*.tr) and collect performance data.
Example of analyzing traffic using AWK:
awk ‘{if ($1==”r” && $4==”AGT” && $7==”UDP”) print $0}’ vlan_simulation.tr
- Advanced Features (Optional):
- Simulate VLAN Priority (QoS): We can replicate QoS depends on VLAN tags by allocating priority to traffic from distinct VLANs and executing priority queuing on switches.
- Simulate Dynamic VLAN Assignment: We can replicate dynamic VLAN assignment according to port-based or MAC-based rules, in which nodes are allocated to VLANs dynamically during the simulation.
- Simulate Inter-VLAN Routing: Execute inter-VLAN routing in which traffic among distinct VLANs is permitted via a router (Layer 3 switch).
We systematically presented the common procedure with instances for IEEE 802.1Q VLAN Tagging projects, simulated and analysed using NS2 platform. If you require further informations and comprehensive details on this topic, we will be made available.
We provide you with useful advice and a clear explanation by providing all relevant IEEE 802.1Q VLAN Tagging Projects information, enabling you to achieve the best simulation results.
