Reducing Latency in Internet Access Links with Mechanisms in Endpoints and within the Network

Excessive and unpredictable end-to-end latency is a major problem for today’s Internet performance, affecting a range of applications from real-time multimedia to web traffic. This is mainly attributed to the interaction between the TCP congestion control mechanism and the unmanaged large buffers deployed across the Internet. This dissertation investigates transport and link layer solutions to solve the Internet’s latency problem on the access links. These solutions operate on the sender side, within the network or use signaling between the sender and the network based on Explicit Congestion Notification (ECN). By changing the sender’s reaction to ECN, a method proposed in this dissertation reduces latency without harming link utilization. Real-life experiments and simulations show that this goal is achieved while maintaining backward compatibility and being gradually deployable on the Internet. This mechanism’s fairness to legacy traffic is further improved by a novel use of ECN within the network

A NEAT Way to do Network Programming

This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the author(s)Peer reviewedPreprin

De-ossifying the Internet Transport Layer : A Survey and Future Perspectives

ACKNOWLEDGMENT The authors would like to thank the anonymous reviewers for their useful suggestions and comments.Peer reviewedPublisher PD

Operating ranges, tunability and performance of CoDel and PIE

COMCOM-D-15-00474R1 This work was part-funded by the European Community under its Seventh Framework Programme through the Reducing Internet Transport Latency (RITE) project (ICT-317700). The views expressed are solely those of the authors.Peer reviewedPostprin

Characterization Guidelines for Active Queue Management (AQM)

Unmanaged large buffers in today’s networks have given rise to a slew of performance issues. These performance issues can be addressed by some form of Active Queue Management (AQM) mechanism, optionally in combination with a packet-scheduling scheme such as fair queuing. This document describes various criteria for performing characterizations of AQM schemes that can be used in lab testing during development, prior to deployment

NEAT : A Platform- And Protocol-Independent Internet Transport API

ACKNOWLEDGMENT The authors would like to thank the anonymous reviewers for their useful remarks. This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the authors.Peer reviewedPostprin

Size-Based and Direction-Based TCP Fairness Issues in IEEE 802.11 WLANs

Cross-layer interaction of Distributed Coordination Function (DCF) of 802.11 MAC protocol and TCP transport protocol leads to two types of unfairness. In a mixed traffic scenario, short-lived TCP flows suffer from poor performance compared to the aggressive long-lived flows. Since the main source of Internet traffic is small file web transfers, this issue forms a major challenge in current WLANs which is called size-based unfairness. In addition, when sharing an access point bottleneck queue, upstream flows impede the performance of downstream flows resulting in direction-based unfairness. Proposed solutions in the literature mostly rely on size-based scheduling policies. However, each proposed method is able to solve any of these two mentioned aspects, none of them can provide both size-based and direction-based fairness in a unique solution. In this paper, we propose a novel queue management policy called Threshold-Based Least Attained Service-Selective Acknowledgment Filtering (TLAS-SAF). We show analytically and by simulation that TLAS-SAF is capable of providing both direction-based and size-based fairness and can be taken into account as a unique solution to be applied at access point buffers. © 2010 Naeem Khademi and Mohamed Othman. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

The New AQM Kids on the Block: Much Ado About Nothing?

Active Queue Management (AQM) design has again come into the spotlight of network operators, vendors and OS developers. This reflects the growing concern and sensitivity about the end-to-end latency perceived by today’s Internet users. Indeed, delays on the order of seconds have become common due to the deployment of excessively-sized FIFO/DropTail buffers at the edge of many networks. CoDel and PIE are two AQM mechanisms that have recently been presented and discussed at the IRTF and the IETF. However, to the best of our knowledge, they have not yet been thoroughly evaluated or compared against each other except by simulation. We set thus to perform an experimental evaluation using real-world implementations, in both wired and wireless testbeds. We have in addition compared them with a decade-old variant of RED called Adaptive RED, which shares with CoDel and PIE the goal of “knob-free” operation. Surprisingly, in many instances results were much more favorable towards Adaptive RED. We do not call into question the need for new AQMs, however, there are lessons yet to be learned from old designs

Coupled Congestion Control for RTP Media

Congestion occurs at a bottleneck along an Internet path; multiple flows between the same sender and receiver pairs can benefit from using only a single congestion control instance when they share the same bottleneck. These benefits include the ability to control the rate allocation between flows and reduced overall delay (multiple congestion control instances cause more queuing delay than one since each has no knowledge of the congestion episodes experienced by the others). We present a mechanism for coupling congestion control for real-time media and show its benefits by coupling multiple congestion controlled flows that share the same bottleneck

Using delay-gradient TCP for multimedia-friendly 'background' transport in home networks

Home networks are seeing increased deployment of Wireless LAN (WiFi) links between conventional, gigabit/second wired Ethernet segments. This means an increasing number of internal bottlenecks, even as home networks are also expected to support latency-sensitive applications, regular TCP flows and an emerging class of low-priority, time-insensitive 'background' TCP flows. This paper explores the novel use of CDG v0.1 (a delay-gradient TCP) for such background TCP connections in home networks. We show a CDG flow induces latencies of only tens of milliseconds regardless of the bottleneck's internal buffer size (useful when coexisting with latency-sensitive traffic) while achieving a significant fraction of spare link capacity. We also show CDG does not gratuitously steal capacity from commonly deployed 'foreground' TCPs such as CUBIC and NewReno