How to Implement QoS aware Clustering in NS2
To implement QoS-aware clustering in NS2 has numerous steps to follow that includes permutation nodes in a network into clusters and make sure that cluster head nodes (CHs) and other nodes interact efficiently however meeting Quality of Service (QoS) requirements. Clustering is usually used in Wireless Sensor Networks (WSNs) and Mobile Ad Hoc Networks (MANETs) to minimize energy consumption, maximize network scalability, and enhance the routing process.
In a QoS-aware clustering scenario, cluster heads are chosen based on criteria such as node energy, bandwidth, or communication delay, and the interaction within clusters and among clusters is handled to make sure QoS metrics such as delay, throughput, and packet loss are enhanced.
The below is the guide on how to implement QoS-aware clustering in NS2:
Steps-by-Step Implementation:
- Understand the Clustering Process
In a typical clustering process:
- Cluster formation: Nodes in a network are grouped into clusters.
- Cluster head selection: A node is chosen as the cluster head based on specific criteria like energy, bandwidth.
- Intra-cluster communication: Nodes interacts with the cluster head.
- Inter-cluster communication: Cluster heads interact with each other or with a base station.
- Basic Setup: Create Nodes and Links
Initiate by configuring a wireless network with multiple nodes that will be grouped into clusters.
# Create a simulator instance
set ns [new Simulator]
# Open trace file
set tracefile [open “qos_clustering_trace.tr” w]
$ns trace-all $tracefile
# Define a topography (for wireless nodes)
set topo [new Topography]
$topo load_flatgrid 1000 1000 ;# Define a 1000×1000 grid area
# Create wireless channel and define other components
set chan_1_ [new Channel/WirelessChannel]
set prop [new Propagation/TwoRayGround]
set netif [new Phy/WirelessPhy]
set mac [new Mac/802_11]
set ll [new LL]
set ifq [new Queue/DropTail/PriQueue]
set ant [new Antenna/OmniAntenna]
# Configure wireless nodes
$ns node-config -adhocRouting AODV \
-llType $ll \
-macType $mac \
-ifqType $ifq \
-ifqLen 50 \
-antType $ant \
-propType $prop \
-phyType $netif \
-channel $chan_1_
# Create mobile nodes (sensor nodes)
for {set i 0} {$i < 20} {incr i} {
set node($i) [$ns node]
$node($i) random-motion 0 ;# Disable random motion for stationary nodes
}
- Cluster Head Selection Based on QoS Parameters
In a QoS-aware clustering scenario, the cluster head (CH) is designated according on metrics like available bandwidth, residual energy, or communication delay. Here, we replicate this by choose nodes based on their available resources.
We can replicate QoS-based selection criteria using a simple decision-making algorithm, like prioritize the node with the highest bandwidth or energy as the cluster head.
# Procedure to select cluster head based on QoS criteria (e.g., energy)
proc select_cluster_heads {nodes} {
set ch_nodes {}
foreach node $nodes {
set energy [get_energy $node]
if {$energy > 0.7} {
lappend ch_nodes $node
}
}
return $ch_nodes
}
# Placeholder function to simulate energy calculation
proc get_energy {node} {
# Simulate the energy calculation (for simplicity, return a random value)
return [expr rand()]
}
# Select cluster heads
set cluster_heads [select_cluster_heads [array names node]]
puts “Cluster heads selected: $cluster_heads”
In this sample, select_cluster_heads selects nodes with energy greater than 0.7 as cluster heads. We can adjust the logic to contain other QoS parameters such as bandwidth or communication delay.
- Intra-Cluster and Inter-Cluster Communication
Once the cluster heads are chosen, we can describe an intra-cluster communication (between cluster members and their CHs) and inter-cluster communication (between CHs and other CHs or the base station).
Intra-Cluster Communication:
# Intra-cluster communication (nodes communicate with their cluster head)
proc intra_cluster_comm {node ch} {
global ns
# Define communication between node and cluster head
set udp [new Agent/UDP]
$ns attach-agent $node $udp
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set packetSize_ 512
$cbr set rate_ 64Kb ;# Define QoS for intra-cluster communication
set null [new Agent/Null]
$ns attach-agent $ch $null
# Connect node to its cluster head
$ns connect $udp $null
}
# Define communication for all cluster members
foreach node $nodes {
# Select a cluster head randomly (in a real scenario, it would be based on distance, etc.)
set random_ch [lindex $cluster_heads [expr {int(rand() * [llength $cluster_heads])}]]
intra_cluster_comm $node $random_ch
}
Inter-Cluster Communication:
Once data is collected at the cluster head, it can be transferred to other cluster heads or a base station.
# Inter-cluster communication (CHs communicate with each other or a base station)
proc inter_cluster_comm {ch1 ch2} {
global ns
set udp [new Agent/UDP]
$ns attach-agent $ch1 $udp
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set packetSize_ 1024
$cbr set rate_ 128Kb ;# Higher QoS for inter-cluster communication
set null [new Agent/Null]
$ns attach-agent $ch2 $null
# Connect cluster heads
$ns connect $udp $null
}
# Connect all cluster heads to each other (for simplicity, a full mesh)
foreach ch1 $cluster_heads {
foreach ch2 $cluster_heads {
if {$ch1 != $ch2} {
inter_cluster_comm $ch1 $ch2
}
}
}
- Implement QoS-Aware Routing and Queuing
To select traffic within the clusters based on QoS that can configure priority queues to make sure that traffic with higher QoS requirements such as real-time data is sent before lower-priority traffic.
# Assign priorities to traffic for QoS-aware routing
proc assign_qos_priority {udp traffic_type} {
if {$traffic_type == “real-time”} {
$udp set prio_ 1 ;# High priority for real-time traffic
} else {
$udp set prio_ 2 ;# Lower priority for non-real-time traffic
}
}
# Example usage
set udp [new Agent/UDP]
assign_qos_priority $udp “real-time”
- Run the Simulation
After configuring the nodes, cluster heads, intra-cluster, and inter-cluster communication, we can execute the simulation.
# Define the simulation duration
$ns at 100.0 “finish”
proc finish {} {
global ns tracefile
$ns flush-trace
close $tracefile
exit 0
}
# Run the simulation
$ns run
- Analyse the Results
Once the simulation done, we can evaluate the trace files to assess the performance of the clustering and QoS mechanisms. Metrics to consider include:
- Throughput: Make sure that high-priority traffic gets higher throughput.
- End-to-end delay: validates if real-time traffic experiences minimal delay.
- Packet delivery ratio: Evaluate the percentage of successfully delivered packets, specifically for high-priority traffic.
In this process, we had detailed covered the information about QoS-aware clustering implementation procedures and evaluation process of QoS-aware clustering outcomes across the ns2 tool. Further details regarding the QoS-aware clustering will be provided in upcoming manuals. Receive the best QoS aware Clustering in NS2 installation assistance from our professionals, who ensure timely delivery and optimal results. If you’re looking for further advice, ns2project.com is the ideal resource.