When bottleneck buffers are large, loss-based congestion control keeps them full, causing bufferbloat When bottleneck buffers are small, loss-based congestion control misinterprets loss as a signa

https://dl.acm.org/doi/pdf/10.1145/3009824

BBR: congestion-based congestion control

We present our experience with QUIC, an encrypted, multiplexed, and low-latency transport protocol designed from the ground up to improve transport performance for HTTPS traffic and to enable rapid deployment and continued evolution of transport mechanisms. QUIC has been globally deployed at Google on thousands of servers and is used to serve traffic to a range of clients including a widely-used web browser (Chrome) and a popular mobile video streaming app (YouTube). We estimate that 7% of Internet traffic is now QUIC. We describe our motivations for developing a new transport, the principles that guided our design, the Internet-scale process that we used to perform iterative experiments on QUIC, performance improvements seen by our various services, and our experience deploying QUIC globally. We also share lessons about transport design and the Internet ecosystem that we learned from our deployment.

https://dl.acm.org/doi/pdf/10.1145/3098822.3098842

The QUIC Transport Protocol: Design and Internet-Scale Deployment

Near Field Communication (NFC) as a promising short range wireless communication technology facilitates mobile phone usage of billions of people throughout the world that offers diverse services ranging from payment and loyalty applications to access keys for offices and houses. Eventually NFC technology integrates all such services into one single mobile phone. NFC technology has emerged lately, and consequently not much academic source is available yet. On the contrary, due to its promising business case options, there will be an increasing amount of work to be studied in the very close future. This paper presents the concept of NFC technology in a holistic approach with different perspectives, including communication essentials with standards, ecosystem and business issues, applications, and security issues. Open research areas and further recommended studies in terms of academic and business point of view are also explored and discussed at the end of each major subject's subsection. This comprehensive survey will be a valuable guide for researchers and academicians as well as for business world interested in NFC technology.

A Survey on Near Field Communication (NFC) Technology

When bottleneck buffers are large, loss-based congestion control keeps them full, causing bufferbloat. When bottleneck buffers are small, loss-based congestion control misinterprets loss as a signal of congestion, leading to low throughput. Fixing these problems requires an alternative to loss-based congestion control. Finding this alternative requires an understanding of where and how network congestion originates.

https://dl.acm.org/doi/pdf/10.1145/3012426.3022184

BBR: Congestion-Based Congestion Control: Measuring bottleneck bandwidth and round-trip propagation time

Most content providers are interested in providing good video delivery QoE for all users, not just on average. State-of-the-art ABR algorithms like BOLA and MPC rely on parameters that are sensitive to network conditions, so may perform poorly for some users and/or videos. In this paper, we propose a technique called Oboe to auto-tune these parameters to different network conditions. Oboe pre-computes, for a given ABR algorithm, the best possible parameters for different network conditions, then dynamically adapts the parameters at run-time for the current network conditions. Using testbed experiments, we show that Oboe significantly improves BOLA, MPC, and a commercially deployed ABR. Oboe also betters a recently proposed reinforcement learning based ABR, Pensieve, by 24% on average on a composite QoE metric, in part because it is able to better specialize ABR behavior across different network states.

https://dl.acm.org/doi/pdf/10.1145/3230543.3230558

Oboe: auto-tuning video ABR algorithms to network conditions

To serve users quickly, Web service providers build infrastructure closer to clients and use multi-stage transport connections. Although these changes reduce client-perceived round-trip times, TCP's current mechanisms fundamentally limit latency improvements. We performed a measurement study of a large Web service provider and found that, while connections with no loss complete close to the ideal latency of one round-trip time, TCP's timeout-driven recovery causes transfers with loss to take five times longer on average.In this paper, we present the design of novel loss recovery mechanisms for TCP that judiciously use redundant transmissions to minimize timeout-driven recovery. Proactive, Reactive, and Corrective are three qualitatively-different, easily-deployable mechanisms that (1) proactively recover from losses, (2) recover from them as quickly as possible, and (3) reconstruct packets to mask loss. Crucially, the mechanisms are compatible both with middleboxes and with TCP's existing congestion control and loss recovery. Our large-scale experiments on Google's production network that serves billions of flows demonstrate a 23% decrease in the mean and 47% in 99th percentile latency over today's TCP.

/pdf/reducing-web-latency-the-virtue-of-gentle-aggression-3psqhlscob.pdf

Reducing web latency: the virtue of gentle aggression

People increasingly use mobile devices as their primary means to access the Internet While it is well known that cellular network operators employ middleboxes, the details of their behavior and their impact on Web performance are poorly understood This paper presents an analysis of proxy behavior and how transparent Web proxies interact with HTTP traffic in four major US cell carriers We find that all four carriers use these proxies to interpose on HTTP traffic, but they vary in terms of whether they perform object caching, traffic redirection, image compression, and connection reuse For example, some transparent proxies unilaterally lower the quality of images, which improves object fetch time but may hurt user satisfaction We also find that these proxies do not necessarily enhance performance for mobile Web workloads in terms of object fetch times; namely, we observe noticeable benefits only when flow sizes are large and the path between the server and proxy exhibits large latency and/or loss

Investigating Transparent Web Proxies in Cellular Networks

Large flows like videos consume significant bandwidth. Some ISPs actively manage these high volume flows with techniques like policing, which enforces a flow rate by dropping excess traffic. While the existence of policing is well known, our contribution is an Internet-wide study quantifying its prevalence and impact on video quality metrics. We developed a heuristic to identify policing from server-side traces and built a pipeline to deploy it at scale on traces from a large online content provider, collected from hundreds of servers worldwide. Using a dataset of 270 billion packets served to 28,400 client ASes, we find that, depending on region, up to 7% of lossy transfers are policed. Loss rates are on average six times higher when a trace is policed, and it impacts video playback quality. We show that alternatives to policing, like pacing and shaping, can achieve traffic management goals while avoiding the deleterious effects of policing.

https://dl.acm.org/doi/pdf/10.1145/2934872.2934873

An Internet-Wide Analysis of Traffic Policing

As mobile Internet becomes more popular, carriers and content providers must engineer their topologies, routing configurations, and server deployments to maintain good performance for users of mobile devices. Understanding the impact of Internet topology and routing on mobile users requires broad, longitudinal network measurements conducted from mobile devices. In this work, we are the first to use such a view to quantify and understand the causes of geographically circuitous routes from mobile clients using 1.5 years of measurements from devices on 4 US carriers. We identify the key elements that can affect the Internet routes taken by traffic from mobile users (client location, server locations, carrier topology, carrier/content-provider peering). We then develop a methodology to diagnose the specific cause for inflated routes. Although we observe that the evolution of some carrier networks improves performance in some regions, we also observe many clients - even in major metropolitan areas - that continue to take geographically circuitous routes to content providers, due to limitations in the current topologies.

/pdf/diagnosing-path-inflation-of-mobile-client-traffic-1nrxumrs82.pdf

Diagnosing Path Inflation of Mobile Client Traffic

Initially, packet forwarding in the Internet was destination-based -- that is, a router would forward all packets with the same destination address to the same next hop. In this paper, we use active probing methods to quantify and characterize deviations from destination-based forwarding in today's Internet. From over a quarter million probes, we analyze the forwarding behavior of almost 40,000 intermediate routers. We find that, for 29% of the targeted routers, the router forwards traffic going to a single destination via different next hops, and 1.3% of the routers even select next hops in different ASes. Load balancers are unlikely to explain these AS-level variations, and in fact we uncover causes including routers inside MPLS tunnels that otherwise employ default routes. We also find that these violations can significantly affect the results of measurement tools that rely on destination-based forwarding, and we discuss some ideas for making these tools more robust against these violations.

https://enl.usc.edu/~tobiasflach/publications/Flach_Violations.pdf

Tobias Flach

Papers

Reducing web latency: the virtue of gentle aggression

Investigating Transparent Web Proxies in Cellular Networks

An Internet-Wide Analysis of Traffic Policing

Diagnosing Path Inflation of Mobile Client Traffic

Quantifying violations of destination-based forwarding on the internet