In this paper we consider transport layer approaches for achieving high rate, low delay communication over edge paths where the bottleneck is a modern WLAN which can aggregate multiple packets into each WLAN frame. We show that regulating send rate so as to maintain a target aggregation level can be used to avoid queue buildup at the WLAN AP. We derive an approximate downlink throughput model for WLANs using aggregation, verify its accuracy using experimental measurements and using this determine a convex low delay rate region. This allows us to derive a low delay proportional fair rate allocation for which we present a prototype transport layer implementation.
In recent years there has been an upsurge in interest in userspace transports due to their flexibility and support for innovation combined with ease of rollout. This has been greatly facilitated by the high efficiency possible in userspace with the support of modern kernels. Notable examples of new transports developed in this way include Google QUIC @cite_14 , UDT @cite_9 and Coded TCP @cite_18 @cite_4 @cite_2 . ETSI has also recently set up a working group to study next generation protocols for 5G @cite_15 . The use of performance enhancing proxies, including in the context of WLANs, is also not new e.g. RFC3135 @cite_0 provides an entry point into this literature. However, none of these exploit the use of aggregation in WLANs to achieve high rate, low delay communication.
@cite_18 @cite_14 @cite_4 @cite_9 @cite_0 @cite_2 @cite_15
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United States. Dept. of Defense. Assistant Secretary of Defense for Research & Engineering (United States. Air Force Contract FA8721-05-C-0002) QUIC (Quick UDP Internet Connection) is a new multiplexed and secure transport atop UDP, designed from the ground up and optimized for HTTP 2 semantics. While built with HTTP 2 as the primary application protocol, QUIC builds on decades of transport and security experience, and implements mechanisms that make it attractive as a modern general- purpose transport. QUIC provides multiplexing and flow control equivalent to HTTP 2, security equivalent to TLS, and connection semantics, reliability, and congestion control equivalent to TCP. This draft documents the early deployment of the QUIC protocol prior to standardization. In this paper, we consider the design of forward error correction tailored specifically for the low end-to-end latency requirements in 5G networks. We present experimental results that highlight a number of issues with conventional approaches and then introduce a new low delay code construction that achieves a superior throughput-delay tradeoff. We analyze its performance both mathematically and experimentally. The mathematical analysis of throughput and delay requires the development of a number of novel analytic tools based on both queuing and coding theories. We implement the low delay code and evaluate its performance in an experimental test bed. In this paper, we summarize our work on the UDT high performance data transport protocol over the past four years. UDT was designed to effectively utilize the rapidly emerging high-speed wide area optical networks. It is built on top of UDP with reliability control and congestion control, which makes it quite easy to install. The congestion control algorithm is the major internal functionality to enable UDT to effectively utilize high bandwidth. Meanwhile, we also implemented a set of APIs to support easy application implementation, including both reliable data streaming and partial reliable messaging. The original UDT library has also been extended to Composable UDT, which can support various congestion control algorithms. We will describe in detail the design and implementation of UDT, the UDT congestion control algorithm, Composable UDT, and the performance evaluation. This document is a survey of Performance Enhancing Proxies (PEPs) often employed to improve degraded TCP performance caused by characteristics of specific link environments, for example, in satellite, wireless WAN, and wireless LAN environments. Different types of Performance Enhancing Proxies are described as well as the mechanisms used to improve performance. Emphasis is put on proxies operating with TCP. In addition, motivations for their development and use are described along with some of the consequences of using them, especially in the context of the Internet. High-performance real-time applications, expected to be of importance in the upcoming 5G era, such as virtual and augmented reality or tele-presence, have stringent requirements on throughput and per-packet in-order delivery delay . Use of multipath transport is gaining momentum for supporting these applications. However, building an efficient, low latency multipath transfer mechanism remains highly challenging. The primary reason for this is that the delivery delay along each path is typically uncertain and time-varying. When the transmitter ignores the stochastic nature of the path delays, then packets sent along different paths frequently arrive out of order and need to be buffered at the receiver to allow in-order delivery to the application. In this paper, we propose Stochastic Earliest Delivery Path First (S-EDPF), a generalization of EDPF which takes into account uncertainty and time-variation in path delays yet has low-complexity suited to practical implementation. Moreover, we integrate a novel low-delay Forward Error Correction (FEC) scheme into S-EDPF in a principled manner by deriving the optimal schedule for coded packets across multiple paths. Finally, we demonstrate, both analytically and empirically, that S-EDPF is effective at mitigating the delay impact of reordering and loss in multipath transport protocols, offering substantial performance gains over the state of the art.