QoS-driven Autonomic Abilities through a Multi-homed Transport Protocol

With the development of Internet technologies, distributed and multimedia applications are more and more used. Because these applications have Quality of Service (QoS) expectations (bounded delay, guaranteed bandwidth, etc.), a set of QoS oriented protocols aimed at aiding end-to-end communications are proposed. Each one of these protocols offers one or several mechanisms. Selecting the best protocol with the best mechanism(s) according to the application requirements and network contexts is a challenge if we want to provide enough QoS to the final users. Also because contexts can evolve, for example when network characteristics change, the previous selected protocol can become obsolete. In this context, an adaptation is mandatory. In this paper, we show how the OSI transport layer can become autonomic in order to perform dynamically reconfiguration actions when it is needed. Our approach consists in including at the transport layer the MAPE loop of the autonomic computing proposal to monitor and analyze the communication in order to predict or to detect a QoS degradation induced by changes of network context, and to plan and execute dynamically new reconfiguration actions in order to keep the communication at the expected QoS level. To implement and evaluate our approach, we extend the new Multipath-TCP (MPTCP) protocol, which offers an extensible application oriented layer. This layer gives opportunity to deploy QoS-aware mechanisms. The test results show that the consumption time of autonomic selection and composition of these mechanisms at run time does not prevent enhancing the QoS, and encourage us to continue working in this approach.