An experimental evaluation of MPTCP-tunnel-based hybrid access

Abstract

In numerous countries, the nation-wide roll-out of high-speed Internet access is progressing slowly, in particular in rural areas, where the investment of laying fiber is high compared to potential revenue. Regulatory pressure however has forced ISPs to act and to provide reliable broadband services to all. The solution that has been deployed or is currently being trialed in various countries is to bond existing DSL with existing high-speed wireless data access provided by LTE to deliver an adequate aggregate bandwidth. There are currently at least two technologies being used, based on either layer-3 tunnels (implemented using GRE) or multi-path TCP (MPTCP) proxies that translate regular TCP into a multi-path TCP connection for the access segment of an end-to-end path. In both cases, the respective protocols cannot be used simply as is as either protocol extensions are needed or some sort of elaborate logic needs to be implemented to deal with issues such as packet reordering. Alternatively, it would be possible to simply use MPTCP unmodified as an underlying transport protocol for existing tunneling technologies such as SSH or OpenVPN. Such an approach could be used today without any modifications to software or protocols. While layer-7 tunneling over an MPTCP transport comes with its own merits it has potential drawbacks, such as bad interactions of congestion control feedback loops. In this paper, we experimentally demonstrate the properties of such an approach and contrast the properties of all three approaches as technologies to provide high-speed, reliable broadband to end consumers.