Multipath in the middle(box)

Multipath TCP (MPTCP) is a major modification to TCP that enables a single transport connection to use multiple paths. Smartphones can benefit from MPTCP by using both WiFi and 3G/4G interfaces for their data-traffic, potentially improving the performance and allowing mobility through vertical handover. However, MPTCP requires a modification of the end hosts, thus suffers from the chicken-and-egg deployment problem. A global deployment of MPTCP is therefore expected to take years. To increase the incentives for clients and servers to upgrade their system, we propose MiMBox an efficient protocol converter that can translate MPTCP into TCP and vice versa to provide multipath benefits to early adopters of MPTCP. MiMBox is application agnostic and can be used transparently or explicitly. Moreover, a close attention was paid to the implementation's design to achieve good forwarding performance. MiMBox is implemented entirely in the Linux kernel so that it is able to more easily circumvent the bottlenecks of a user-space implementation. Measurements show that we always outperform user-space solutions and that the performance is close to plain IP packet forwarding.