To implement data compression in ns3, we need to create an application that compresses data before transmission and decompress it upon reception. This helps to save the bandwidth and to improve the efficiency of the network. Here is a complete guide to implement data compression in ns3.
Steps for implementation
Step 1: Set up the simulation
Make sure that ns3 is installed in the computer. If not, install it from the official ns3 website.
Step 2: Create a New Simulation Script
In the scratch directory of our ns3, we should create a simulation script. In our example, let’s create a file named data_compression.cc.
Step 3: Include Necessary Headers
Include all the necessary ns3 headers in our script.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/wifi-module.h”
#include “ns3/mobility-module.h”
#include “ns3/applications-module.h”
#include <zlib.h>
using namespace ns3;
Step 4: Define Command-Line Arguments for Parameterization
Define parameters that can be set through the command line.
int main(int argc, char *argv[])
{
uint32_t numNodes = 2;
double simTime = 10.0;
CommandLine cmd;
cmd.AddValue(“numNodes”, “Number of nodes”, numNodes);
cmd.AddValue(“simTime”, “Simulation time (seconds)”, simTime);
cmd.Parse(argc, argv);
NodeContainer nodes;
nodes.Create(numNodes);
YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default();
YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default();
wifiPhy.SetChannel(wifiChannel.Create());
WifiHelper wifi;
wifi.SetStandard(WIFI_STANDARD_80211n);
WifiMacHelper wifiMac;
wifiMac.SetType(“ns3::AdhocWifiMac”);
NetDeviceContainer devices = wifi.Install(wifiPhy, wifiMac, nodes);
MobilityHelper mobility;
mobility.SetMobilityModel(“ns3::ConstantPositionMobilityModel”);
mobility.Install(nodes);
InternetStackHelper stack;
stack.Install(nodes);
Ipv4AddressHelper address;
address.SetBase(“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces = address.Assign(devices);
// Install applications
uint16_t port = 9;
OnOffHelper onoff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(interfaces.GetAddress(numNodes-1), port)));
onoff.SetConstantRate(DataRate(“500kbps”));
ApplicationContainer apps = onoff.Install(nodes.Get(0));
apps.Start(Seconds(1.0));
apps.Stop(Seconds(simTime));
PacketSinkHelper sink(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address::GetAny(), port)));
apps = sink.Install(nodes.Get(numNodes-1));
apps.Start(Seconds(0.0));
apps.Stop(Seconds(simTime));
Simulator::Stop(Seconds(simTime));
Simulator::Run();
Simulator::Destroy();
return 0;
}
Step 5: Implement Data Compression and Decompression Functions
To compress and decompress data, implement functions using zlib.
std::string CompressData(const std::string& data)
{
z_stream zs;
memset(&zs, 0, sizeof(zs));
if (deflateInit(&zs, Z_BEST_COMPRESSION) != Z_OK)
{
throw(std::runtime_error(“deflateInit failed while compressing.”));
}
zs.next_in = (Bytef*)data.data();
zs.avail_in = data.size();
int ret;
char outbuffer[32768];
std::string outstring;
do
{
zs.next_out = reinterpret_cast<Bytef*>(outbuffer);
zs.avail_out = sizeof(outbuffer);
ret = deflate(&zs, Z_FINISH);
if (outstring.size() < zs.total_out)
{
outstring.append(outbuffer, zs.total_out – outstring.size());
}
} while (ret == Z_OK);
deflateEnd(&zs);
if (ret != Z_STREAM_END)
{
throw(std::runtime_error(“Exception during zlib compression: ” + std::to_string(ret)));
}
return outstring;
}
std::string DecompressData(const std::string& data)
{
z_stream zs;
memset(&zs, 0, sizeof(zs));
if (inflateInit(&zs) != Z_OK)
{
throw(std::runtime_error(“inflateInit failed while decompressing.”));
}
zs.next_in = (Bytef*)data.data();
zs.avail_in = data.size();
int ret;
char outbuffer[32768];
std::string outstring;
do
{
zs.next_out = reinterpret_cast<Bytef*>(outbuffer);
zs.avail_out = sizeof(outbuffer);
ret = inflate(&zs, 0);
if (outstring.size() < zs.total_out)
{
outstring.append(outbuffer, zs.total_out – outstring.size());
}
} while (ret == Z_OK);
inflateEnd(&zs);
if (ret != Z_STREAM_END)
{
throw(std::runtime_error(“Exception during zlib decompression: ” + std::to_string(ret)));
}
return outstring;
}
Step 6: Implement a Custom Application for Compression and Decompression
Create a custom application which compresses data before transmission and decompresses it upon reception.
class CompressionApp : public Application
{
public:
CompressionApp();
virtual ~CompressionApp();
void Setup(Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate);
private:
virtual void StartApplication() override;
virtual void StopApplication() override;
void ScheduleTx();
void SendPacket();
void ReceivePacket(Ptr<Socket> socket);
Ptr<Socket> m_socket;
Address m_peer;
uint32_t m_packetSize;
uint32_t m_nPackets;
DataRate m_dataRate;
EventId m_sendEvent;
bool m_running;
uint32_t m_packetsSent;
};
CompressionApp::CompressionApp()
: m_socket(0), m_peer(), m_packetSize(0), m_nPackets(0), m_dataRate(0), m_sendEvent(), m_running(false), m_packetsSent(0)
{
}
CompressionApp::~CompressionApp()
{
m_socket = 0;
}
void CompressionApp::Setup(Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate)
{
m_socket = socket;
m_peer = address;
m_packetSize = packetSize;
m_nPackets = nPackets;
m_dataRate = dataRate;
}
void CompressionApp::StartApplication()
{
m_running = true;
m_packetsSent = 0;
m_socket->Bind();
m_socket->Connect(m_peer);
m_socket->SetRecvCallback(MakeCallback(&CompressionApp::ReceivePacket, this));
SendPacket();
}
void CompressionApp::StopApplication()
{
m_running = false;
if (m_sendEvent.IsRunning())
{
Simulator::Cancel(m_sendEvent);
}
if (m_socket)
{
m_socket->Close();
}
}
void CompressionApp::SendPacket()
{
std::string data = “Hello, this is a test message.”;
std::string compressedData = CompressData(data);
Ptr<Packet> packet = Create<Packet>((uint8_t *)compressedData.c_str(), compressedData.size());
m_socket->Send(packet);
if (++m_packetsSent < m_nPackets)
{
ScheduleTx();
}
}
void CompressionApp::ScheduleTx()
{
if (m_running)
{
Time tNext(Seconds(m_packetSize * 8 / static_cast<double>(m_dataRate.GetBitRate())));
m_sendEvent = Simulator::Schedule(tNext, &CompressionApp::SendPacket, this);
}
}
void CompressionApp::ReceivePacket(Ptr<Socket> socket)
{
Ptr<Packet> packet;
while ((packet = socket->Recv()))
{
uint8_t *buffer = new uint8_t[packet->GetSize()];
packet->CopyData(buffer, packet->GetSize());
std::string compressedData((char *)buffer, packet->GetSize());
delete[] buffer;
std::string decompressedData = DecompressData(compressedData);
NS_LOG_UNCOND(“Received and decompressed: ” << decompressedData);
}
}
Step 7: Integrate the Custom Application in Your Simulation
Instantiate the CompressionApp application in the main simulation script and attach it to the nodes in your network.
int main(int argc, char *argv[])
{
uint32_t numNodes = 2;
double simTime = 10.0;
CommandLine cmd;
cmd.AddValue(“numNodes”, “Number of nodes”, numNodes);
cmd.AddValue(“simTime”, “Simulation time (seconds)”, simTime);
cmd.Parse(argc, argv);
NodeContainer nodes;
nodes.Create(numNodes);
YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default();
YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default();
wifiPhy.SetChannel(wifiChannel.Create());
WifiHelper wifi;
wifi.SetStandard(WIFI_STANDARD_80211n);
WifiMacHelper wifiMac;
wifiMac.SetType(“ns3::AdhocWifiMac”);
NetDeviceContainer devices = wifi.Install(wifiPhy, wifiMac, nodes);
MobilityHelper mobility;
mobility.SetMobilityModel(“ns3::ConstantPositionMobilityModel”);
mobility.Install(nodes);
InternetStackHelper stack;
stack.Install(nodes);
Ipv4AddressHelper address;
address.SetBase(“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces = address.Assign(devices);
// Create and setup CompressionApp on the first node
Ptr<Socket> sourceSocket = Socket::CreateSocket(nodes.Get(0), TypeId::LookupByName(“ns3::UdpSocketFactory”));
Address sinkAddress(InetSocketAddress(interfaces.GetAddress(1), port));
Ptr<CompressionApp> sourceApp = CreateObject<CompressionApp>();
sourceApp->Setup(sourceSocket, sinkAddress, 1024, 100, DataRate(“1Mbps”));
nodes.Get(0)->AddApplication(sourceApp);
sourceApp->SetStartTime(Seconds(1.0));
sourceApp->SetStopTime(Seconds(simTime));
// Create and setup CompressionApp on the second node
Ptr<Socket> sinkSocket = Socket::CreateSocket(nodes.Get(1), TypeId::LookupByName(“ns3::UdpSocketFactory”));
Ptr<CompressionApp> sinkApp = CreateObject<CompressionApp>();
sinkApp->Setup(sinkSocket, InetSocketAddress(Ipv4Address::GetAny(), port), 1024, 100, DataRate(“1Mbps”));
nodes.Get(1)->AddApplication(sinkApp);
sinkSocket->Bind(InetSocketAddress(Ipv4Address::GetAny(), port));
sinkSocket->SetRecvCallback(MakeCallback(&CompressionApp::ReceivePacket, sinkApp));
sinkApp->SetStartTime(Seconds(1.0));
sinkApp->SetStopTime(Seconds(simTime));
Simulator::Stop(Seconds(simTime));
Simulator::Run();
Simulator::Destroy();
return 0;
}
Step 8: Compile and Run Your Simulation
Compile your simulation script using waf:
./waf configure
./waf build
./waf –run scratch/data_compression
Step 9: Analyze the Output
To ensure that data is being compressed before transmission and decompressed upon reception, analyze the log output.
On the whole, we had a performance analysis on the implementation of data compression using ns3 by creating an application that compresses data before transmission and decompresses it upon reception.
We guarantee top-notch implementation results for Data Compression in all project areas through ns3simulation. Reach out to ns3simulation.com for optimal results.