ECMP Based on Traffic Monitoring

This respository is the project during SDN/NFV course at NCTU in 2018 Spring.

Introduction

With the limitation of load balancing with hash function or other algorithm according to packet header fields, in this porject I present a dynamically scheduling mechanism based on traffic monitoring.

Each switch or router periodically monitors the traffic status of ports and determines next-hop of packets by choosing the least loaded link when flows come in.

In the case of multiple elephant flows between two end devices and with same protocol stacks, such as one user requests for large files from a FTP server, our method can distribute flows to multipaths in a more efficient way.

In the implementation, I use Mininet and run the application on Ryu controller.

Prerequisites

You can install Mininet and Ryu from their GitHub pages.

Usage

In the project, I experiment with a 2x2 leaf-spine topology on Mininet. Each leaf node have two hosts connected to it.

Build up the network environment. You should run with sudo permission.

$ sudo ./2x2LeafSpine.py

At the Mininet shell, open a terminal for the controller.

mininet> xterm c0

After executing the command, a xterm for c0 controller will pop up.

Run the Ryu application at c0 shell.

c0$ ryu run traffic-monitoring-ecmp.py

Now logs of port tranmitted volumn on leaf switch 201 will be shown and refreshed periodically.

To test our application, here provides two UDP file transmission script sender and receiver. For the demonstration, first run receiver on host 303 or 304 to listen on a specified port, and then execute sender on host 301 or 302.

Open a shell for host 303.

mininet> xterm 303

Run receiver script on host 303.

303$ ./receiver <port_to_listen> <saved_filename>

Also open a shell for host 301.

mininet> xterm 301

Run sender script on host 301.

301$ ./sender <receiver_ip> <receiver_port> <transmitted_filename>

Now the file should start to be transmitted and you can see the log for transmitted packets and bytes at controller c0 terminal.

Try to transmit two large files to create elephant flows, and see if they are distributed to different ports. Aslo perform the same procedure with the application traditional-ecmp.py to see the difference.

Details

For more details, please refer to paper.docx or slides.pptx.