Remote Receiver Control in MPTCP Networks in Uncertain Operating Conditions

Owing to the security policies imposed, TCP conveys data for diverse application types, yet not necessarily suitable for the stream-related transport services. While in many contexts high throughput is preferred, other, e.g., multimedia or control system related ones, demand short latencies, rarely obtainable in the TCP scenarios. While such requirement can be fulfilled using appropriate network administration, it is a costly solution. Hence, another approach gains importance - the simultaneous use of separate transmission channels under a common control framework. For that purpose, suitable versions of well-known protocols are being developed. One of them is multipath TCP - MPTCP. The use of parallel channels to transfer the data promises numerous advantages from the application point of view. It also opens new research perspectives concerning data flow optimization. In this paper, a new flow controller, designed for the communication of multihome systems that exchange data using MPTCP protocol is presented. The controller operates on the top of other protocol components and responds properly to the fluctuations observed beneath, e.g., uncertain throughput and delays on the paths and non-optimal stream split ratio. The control algorithm establishes a feasible (non-negative and bounded) input signal and prevents both exhausting and overflowing the receiver buffer despite fluctuating networking conditions. It is executed at the sender side and it does not require any changes at the receiver.