Flow-Monitor in NS3. A Perfect Tool For Evaluation Purposes. (Throughput, Delay, Jitter, Packet Loss and Other Parameters in NS3)

Flow Monitor:

                A set of evaluation criteria are the focus of every simulation, using which a proposed scheme can be evaluated. In communications, specifically wireless communications, more specifically LTE, major evaluation criteria are:

• -          Delay (end-to-end mean delay)
• -          Throughput
• -          Packet loss ratio
• -          Mean Jitter
• -          Mean transmitted packet size (bytes)
• -          Mean received packet size (bytes)
• -          Means transmitted bitrate (bit/s)
• -          Means received bitrate (bit/s)
• -          Mean hop count
• -          Lost packets

In any NS3 simulations, you can easily calculate parameters mentioned above using FLOW-MONITOR.

How to use flow-monitor in code:

1-      Include flow-monitor header file.

#include "ns3/flow-monitor-module.h"

2-      Add following code snippet before “Simulator∷ Stop();”. This code will assign a monitor to each node.

Ptr<FlowMonitor> flowMonitor;

FlowMonitorHelper flowHelper;

flowMonitor = flowHelper.InstallAll();

Simulator::Stop(Seconds(simTime));

If you are interested in installing monitor to each node separately, then use “Install” method instead of “InstallAll”. But I would prefer to install flow-monitor on all nodes J .

flowMonitor = flowHelper.Install (nodes);

3-      Finally, we print output to an XML file. Add this line after “Simulator∷ Run();”.

flowMonitor->SerializeToXmlFile("NameOfFile.xml", true, true);

That’s it. Using above three steps, you can easily add flow monitor to all node. The NameOfFile.XML file will be generated in your NS3 directory.

How to visualize output:

The XML file can be viewed by any XML viewer. I found NetAnim (A basic guide to netanim is here) to be the best viewer for the flow monitor.

1-      Open NetAnim (Make sure you see three tabs in netanim, Animator, Stats, and Packets)

2-      Click “Stats” tab

3-      From dropdown menu, select Flow-monitor. (The dropdown menu will show IP-MAC in start)

4-      Click “FlowMon file” button on the right.

5-      Browse to your NS3 directory and select “NameOfFile.XML” file.

6-      The file will display every flow with its parameters and values.

For your convenience J .

 

Using all these values, many evaluation parameters can be calculated. Next section will show you how to calculate those parameters from these values.

Parameters:

Some parameters are directly calculated and rest can be calculated using these formulae.

Throughput (bps): rxBytes*8 / [(timeLastRxPacket/1,000,000,000)- (timeFirstRxPacket/1,000,000,000)]

And

Throughput (Mbps): rxBytes*8 / [(timeLastRxPacket/1,000,000,000)- (timeFirstRxPacket/1,000,000,000)] / 1024 / 1024

 

References and material:

1. FlowMonitor — a network monitoring framework for the Network Simulator 3 (NS-3), online: http://telecom.inesctec.pt/~gjc/flowmon-presentation.pdf
2. NS-3 Advanced Tutorial: Visualization and Data Collection, Online: https://www.nsnam.org/tutorials/consortium13/visualization-tutorial.pdf
3. https://www.nsnam.org/docs/models/html/flow-monitor.html
4. Throughput: http://comments.gmane.org/gmane.network.simulator.ns3.user/18301
5. https://groups.google.com/forum/#!topic/ns-3-users/NuScxlCA8H0
6. https://groups.google.com/forum/#!msg/ns-3-users/Z2pgY6tbJgM/viiOwlfeu4kJ
7. https://groups.google.com/forum/#!topic/ns-3-users/8rxd2VfHsFg
8. https://groups.google.com/forum/#!topic/ns-3-users/nXuyOZaazbU