Multipath TCP: Analysis, Design and Implementation

TL;DR

This paper presents a comprehensive analysis, design, and implementation of Multi-path TCP, introducing a fluid model, design criteria, and a new algorithm that balances TCP-friendliness, responsiveness, and stability, with real-world Linux kernel implementation.

Contribution

It develops a fluid model for MP-TCP, proposes a new balanced algorithm, and demonstrates its effectiveness through Linux kernel implementation and comparison with existing algorithms.

Findings

The new algorithm balances TCP-friendliness, responsiveness, and window stability.

The fluid model guarantees existence, uniqueness, and stability of system equilibrium.

Implementation in Linux kernel shows practical viability and performance improvements.

Abstract

Multi-path TCP (MP-TCP) has the potential to greatly improve application performance by using multiple paths transparently. We propose a fluid model for a large class of MP-TCP algorithms and identify design criteria that guarantee the existence, uniqueness, and stability of system equilibrium. We clarify how algorithm parameters impact TCP-friendliness, responsiveness, and window oscillation and demonstrate an inevitable tradeoff among these properties. We discuss the implications of these properties on the behavior of existing algorithms and motivate a new design that generalizes existing algorithms and strikes a good balance among TCP-friendliness, responsiveness, and window oscillation. We have implemented our algorithm in the Linux kernel. We use our prototype to compare the new algorithm with existing MP-TCP algorithms.