Implementation and analysis of load balancing techniques in wireless multi hop networks

Nowadays we have seen enormous increase in the use of Wireless networking in our day-to-day life. Wireless technologies are used to provide Internet due to the improvements in the available hardware and advancements in the inventions of routing algorithms. On the contrary, the cost, reliability, quality of service possess some constrains in this sector. Apart from this there has also been a proliferation of applications, which require special traffic treatment, with the need to be free of wired networks. Linux, with their open source, flexible and yet powerful architecture has been the pivotal point for cost reduction in Wireless devices. This inspired and motivated me to develop a novel approach for the implementation of per-packet, per- connection and per-traffic load splitting in Wireless next-hop networks using open source technologies mostly licensed under GNU General Public License. In this thesis, I created an experimental test bed of OpenWrt nodes, starting from building the OpenWrt firmware to the performance evaluation of the different load splitting scenarios. The setup and also the communication between the nodes is taking place in a virtual environment operating on User Mode Linux. After implementation of the load splitting techniques, behavioral tests were conducted on the experimental topology and with the help of performance evaluation, it was evident the influence of transmit queue size on the throughput and also the type of load balancing. At the end of this research the load splitting approach on the virtual test bed was tested for its fairness on presence of one or more traffic flows. Using Jain`s fairness index for two cases of traffic flows that resulted in the range of 0.99-1, fairness of this implementation was proved.

L'uso di tecnologie per connettività wireless è diventato ormai pervasivo. Tale successo è principalmente dovuto alla dispoinibilità via via crescente di hardware con costi accessibili ed a software "accessibile" per lo sviluppo di soluzioni ed applicazioni di diverso tipo. Tuttavia, sussistono ancora molti problemi legati all'affidabilità delle tecnologie, ed alle prestazioni raggiungibili (throughput) se comparate con tecnologie cablate. Nel caso di reti wireless multi-hop, uno dei principali problemi riguarda la gestione dell'instradamento. Questo lavoro di tesi tratta della problematica dell'instradamento su percorsi multipli (multi-path) per reti wireless. In particolare, si sono analizzate diverse politiche per l'implementazione dell'instradamento a percorsi multipli orientate al pacchetto ed alla connessione. Tali politiche sono state implementate all'interno del sistema operativo OpenWRT e successivamente testate in emulazione su scenari di rete semplificati in cui sono stati misurati il throughput, l'impatto della dimensione della coda dei router ed il grado di fairness.