Multipath TCP analysis over SDN network

The origins of the Internet date back to the 1960s when the U.S government conducted research in order to make robust and fault tolerant computer networks for communications. Then in the 1980s ARPANET was used as a backbone connecting the academic and military networks. In that time the funding of this new backbone network was supported by the National Science Foundation but also some private investors funded the building of new commercial backbones. These events led to the development of the Internet. Finally in the 1990s the increased connections of different enterprises and universities defined the Internet as we know it today. Nowadays we live in times in which the Internet is pervasive and it is part of every aspect of our lives. The working of the Internet is based on the TCP/IP paradigm. These are the two protocols which are responsible for the Internet as we know it today. The Internet Protocol is responsible for the addressing which allows interworking, or in other words every host on the Internet has its own unique IP address according to which the packets are sent across the global network. The other protocol is Transport Control Protocol which is a connection oriented protocol responsible for reliable, ordered and error checked transmission of packets across the Internet. TCP was introduced 20 year ago and it hasn’t evolved since then. In that time the designers didn’t considered the evolution of the networks and that in the future one device will have a need to be connected using more than one port, which is happening today. Nowadays networks have evolved since the first introduction of TCP, moreover there is a real need for a device to have a connection through more than one port, which is not supported in TCP. Thus we can say that there is a mismatch between TCP and the modern networks and users. That is why Multipath TCP was introduced. MPTCP supports multiple paths for the same connection that can answer today’s needs. Furthermore it improves the robustness of the network in terms of failures, and increase the throughput and as well the usage of the network resources. In this thesis work we focus on evaluating the performance of MPTCP protocol over SDN based networks. We evaluated the effect of end-to-end delay and delay difference in path on overall MPTCP throughput for different scheduling algorithms of MPTCP. We also check the performance of MPTCP in presence of background traffic to understand how fair MPTCP protocol is when MPTCP and other protocols are present on the same link. We have performed all the tests using our automated test-bed for MPTCP on SDN based network. This thesis is organized in five chapters, in the first chapter we will see what motivated the evolution of TCP towards MPTCP, explain SDN concepts and understand how to achieve maximum benefits out of MPTCP using SDN. The second chapter is the state of the art chapter. In the third chapter we will explain the network topologies that we have used for the test cases for this thesis, all software components used in order to be possible to execute the tests, and finally how we have saved the results of the performed tests. The next chapter is reserved for the test analysis, where we will present the obtained results from the considered tests. We also present a comparison of MPTCP and TCP. In the final chapter we will conclude what we have learned in this thesis.