Over the years, the Internet has been enriched with new available communication technologies, for both fixed and mobile networks and devices, exhibiting an impressive growth in terms of performance, with steadily increasing available data rates. The Internet research community has kept trying to evolve the transport layer protocols to match the capabilities of modern networks, in order to fully reap the benefits of the new communication technologies. This paper surveys the main novelties related to transport protocols that have been recently proposed, identifying three main research trends: (i) the evolution of congestion control algorithms, to target optimal performance in challenging scenarios, possibly with the application of machine learning techniques; (ii) the proposal of brand new transport protocols, alternative to the Transmission Control Protocol (TCP) and implemented in the user-space; and (iii) the introduction of multipath capabilities at the transport layer.

中文翻译：

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传输层协议最新进展综述

多年来，互联网因固定和移动网络和设备的新可用通信技术而丰富，在性能方面表现出令人印象深刻的增长，可用数据速率稳步提高。互联网研究界一直在努力发展传输层协议以匹配现代网络的能力，以充分利用新通信技术的好处。本文调查了最近提出的与传输协议相关的主要创新，确定了三个主要研究趋势：(i) 拥塞控制算法的演变，以在具有挑战性的场景中实现最佳性能，可能与机器学习技术的应用有关；(ii) 提出全新的传输协议，传输控制协议 (TCP) 的替代方案并在用户空间中实现；(iii) 在传输层引入多路径功能。