Description: |
Wireless mesh network is an emerging technology that has many applications, e.g. video surveillance for urban security, wireless broadband access etc. An important engineering issue in WMN is to provide good quality of service for the applications. One such problem is to find a good route for the application. ETX is an example of one such routing protocol, however, there are a number of issues with ETX.
Experiments show that even a single flow can badly affect link ETX (Expected Transmission Count) calculations. ETX is a link quality indicator and shows the expected number of transmission attempts over a link in order to achieve successful delivery of the packet. A bad link would require many more attempts than a good link. ETX is measured through probing the links. It is shown in experiments that the change in the ETX value, when probing is done without and in the presence of a data flow, is almost 10,000%. Such a change indicates that routing protocols, based on ETX, might be playing with random numbers without bringing any significant benefits of considering link quality.
This project involves implementation of probing mechanism on NICTA testbed and performing experiments to quantify the affects of data on ETX metric of links in the radio space. We would compare the ETX metric values with actual data loss on the links to show how accurately (or inaccurately) ETX represents link quality.
The student will also be supervised by Dr. Zainab Zaidi (Zainab.Zaidi@nicta.com.au) from NICTA on this project.
Reference:
Das, S. M., Pucha, H., Papagiannaki, K., and Hu, Y. C. 2007. Studying wireless routing link metric dynamics. In Proceedings of the 7th ACM SIGCOMM Conference on internet Measurement (San Diego, California, USA, October 24 - 26, 2007). IMC '07. ACM, New York, NY, 327-332. |
