ACM SIGCOMM 2020, New York City, USA
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ACM SIGCOMM 2020 Program

Each technical session will have two instances, once in a time zone friendly to the western hemisphere and another in a time zone friendly to the eastern hemisphere.

For each paper presented at each technical session, there will a pre-recorded talk of 10-minute duration and a 5-minute live Q&A conducted by the session chair. Registered attendees may view the talk and live Q&A through a Zoom session link that will be mailed out through the registration system.

Each session has an associated Slack channel for discussion of papers and/or talks. Click on the link "Go to slack channel" under each session title to go to the corresponding channel. If you're asked to sign in, use the workspace name "sigcomm.slack.com" to sign up or sign in.

The full conference proceedings are available at https://dl.acm.org/doi/proceedings/10.1145/3387514. Links to individual papers and 20-minute talk videos (distinct from the 10-minute videos which will be aired during the conference Zoom session) are freely and openly available in the detailed program information below.

  • Tuesday, August 11, 2020 EDT

  • 9:45 - 11:15 am EDT  &  8:45 - 10:15 pm EDT      Opening & Keynote 1

    Go to Slack channel
  • 9:45 - 10:15 am EDT
               &
    8:45 - 9:15 pm EDT

    Opening: Welcome by GCs and PC chairs. Paper and lifetime awards

    Speakers: Vishal Misra (Columbia University, USA), Henning Schulzrinne (Columbia University, USA), Sujata Banerjee (VMware Research), Ratul Mahajan (University of Washington, Intentionet)

  • 10:15 - 11:15 am EDT
               &
    9:15 - 10:15 pm EDT

    Coming of Age in the Fifth Epoch of Distributed Computing: The Power of Sustained Exponential Growth

    Speakers: Amin Vahdat (Google)

    • The annual SIGCOMM Award will be presented to Amin Vahdat for groundbreaking contributions to data center and wide area networks.

       

  • 11:15 - 11:59 am EDT  &  10:15 - 11:00 pm EDT      Technical Session 1: Programming Switches

    Session chairs: Xin Jin (western hemisphere) & Vincent Liu (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Programmable Switches
  • 11:15 - 11:30 am EDT
               &
    10:15 - 10:30 pm EDT

    Switch Code Generation using Program Synthesis

    Xiangyu Gao, Taegyun Kim, Michael D. Wong (New York University); Divya Raghunathan (Princeton University); Aatish Kishan Varma (New York University); Pravein Govindan Kannan (National University of Singapore); Anirudh Sivaraman (New York University); Srinivas Narayana (Rutgers University); Aarti Gupta (Princeton University)

    • Abstract: Writing packet-processing programs for programmable switch pipelines is challenging because of their all-or-nothing nature: a program either runs at line rate if it can fit within pipeline resources, or does not run at all. It is the compiler's responsibility to fit programs into pipeline resources. However, switch compilers, which use rewrite rules to generate switch machine code, often reject programs because the rules fail to transform programs into a form that can be mapped to a pipeline's limited resources---even if a mapping actually exists.

      This paper presents a compiler, Chipmunk, which formulates code generation as a program synthesis problem. Chipmunk uses a program synthesis engine, SKETCH, to transform high-level programs down to switch machine code. However, naively formulating code generation as program synthesis can lead to long compile times. Hence, we develop a new domain-specific synthesis technique, slicing, which reduces compile times by 1-387x and 51x on average.

      Using a switch hardware simulator, we show that Chipmunk compiles many programs that a previous rule-based compiler, Domino, rejects. Chipmunk also produces machine code with fewer pipeline stages than Domino. A Chipmunk backend for the Tofino programmable switch shows that program synthesis can produce machine code for high-speed switches.

       

  • 11:30 - 11:45 am EDT
               &
    10:30 - 10:45 pm EDT

    Composing Dataplane Programs with μP4

    Hardik Soni (Cornell University); Myriana Rifai (Nokia Bell Labs); Praveen Kumar, Ryan Doenges, Nate Foster (Cornell University)

    • Abstract: Dataplane languages like P4 enable flexible and efficient packet-processing using domain-specific primitives such as programmable parsers and match-action tables. Unfortunately, P4 programs tend to be monolithic and tightly coupled to the hardware architecture, which makes it hard to write programs in a portable and modular way---e.g., by composing reusable libraries of standard protocols.

      To address this challenge, we present the design and implementation of a novel framework (μP4) comprising a lightweight logical architecture that abstracts away from the structure of the underlying hardware pipelines and naturally supports powerful forms of program composition. Using examples, we show how enables modular programming. We present a prototype of the compiler that generates code for multiple lower-level architectures, including Barefoot's Tofino Native Architecture. We evaluate the overheads induced by our compiler on realistic examples.

       

  • 11:45 - 11:59 am EDT
               &
    10:45 - 11:00 pm EDT

    Lyra: A Cross-Platform Language and Compiler for Data Plane Programming on Heterogeneous ASICs

    Jiaqi Gao (Alibaba Group and Harvard University); Ennan Zhai, Hongqiang Harry Liu, Rui Miao (Alibaba Group); Yu Zhou (Alibaba Group and Tsinghua University); Bingchuan Tian (Alibaba Group and Nanjing University); Chen Sun, Dennis Cai, Ming Zhang (Alibaba Group); Minlan Yu (Harvard University)

    • Abstract: Programmable data plane has been moving towards deployments in data centers as mainstream vendors of switching ASICs enable programmability in their newly launched products, such as Broadcom's Trident-4, Intel/Barefoot's Tofino, and Cisco's Silicon One. However, current data plane programs are written in low-level, chip-specific languages (e.g., P4 and NPL) and thus tightly coupled to the chip-specific architecture. As a result, it is arduous and error-prone to develop, maintain, and composite data plane programs in production networks. This paper presents Lyra, the first cross-platform, high-level language & compiler system that aids the programmers in programming data planes efficiently. Lyra offers a one-big-pipeline abstraction that allows programmers to use simple statements to express their intent, without laboriously taking care of the details in hardware; Lyra also proposes a set of synthesis and optimization techniques to automatically compile this "big-pipeline" program into multiple pieces of runnable chip-specific code that can be launched directly on the individual programmable switches of the target network. We built and evaluated Lyra. Lyra not only generates runnable real-world programs (in both P4 and NPL), but also uses up to 87.5% fewer hardware resources and up to 78% fewer lines of code than human-written programs.

       

  • 12:00 - 1:00 pm EDT  &  11:00 - 11:59 pm EDT      Technical Session 2: Telemetry: Tell Me More About My Packets

    Session chairs: Arpit Gupta (western hemisphere) & Hongqiang Liu (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Telemetry     Programmable switches
  • 12:00 - 12:15 pm EDT
               &
    11:00 - 11:15 pm EDT

    OmniMon: Re-architecting Network Telemetry with Resource Efficiency and Full Accuracy

    Qun Huang, Haifeng Sun (Peking University; Institute of Computing Technology, Chinese Academy of Sciences); Patrick P. C. Lee (The Chinese University of Hong Kong); Wei Bai (Microsoft Research); Feng Zhu, Yungang Bao (Institute of Computing Technology, Chinese Academy of Sciences)

    • Abstract: Network telemetry is essential for administrators to monitor massive data traffic in a network-wide manner. Existing telemetry solutions often face the dilemma between resource efficiency (i.e., low CPU, memory, and bandwidth overhead) and full accuracy (i.e., error-free and holistic measurement). We break this dilemma via a network-wide architectural design OmniMon, which simultaneously achieves resource efficiency and full accuracy in flow-level telemetry for large-scale data centers. OmniMon carefully coordinates the collaboration among different types of entities in the whole network to execute telemetry operations, such that the resource constraints of each entity are satisfied without compromising full accuracy. It further addresses consistency in network-wide epoch synchronization and accountability in error-free packet loss inference. We prototype OmniMon in DPDK and P4. Testbed experiments on commodity servers and Tofino switches demonstrate the effectiveness of OmniMon over state-of-the-art telemetry designs.

       

  • 12:15 - 12:30 pm EDT
               &
    11:15 - 11:30 pm EDT

    PINT: Probabilistic In-band Network Telemetry

    Ran Ben Basat (Harvard University); Sivaramakrishnan Satyamangalam Ramanathan (University of Southern California); Yuliang Li (Harvard University); Gianni Antichi (Queen Mary University of London); Minlan Yu, Michael Mitzenmacher (Harvard University)

    • Abstract: Commodity network devices support adding in-band telemetry measurements into data packets, enabling a wide range of applications, including network troubleshooting, congestion control, and path tracing. However, including such information on packets adds significant overhead that impacts both flow completion times and application-level performance.

      We introduce PINT, an in-band network telemetry framework that bounds the amount of information added to each packet. PINT encodes the requested data on multiple packets, allowing per-packet overhead limits that can be as low as one bit. We analyze PINT and prove performance bounds, including cases when multiple queries are running simultaneously. PINT is implemented in P4 and can be deployed on network devices.Using real topologies and traffic characteristics, we show that PINT concurrently enables applications such as congestion control, path tracing, and computing tail latencies, using only sixteen bits per packet, with performance comparable to the state of the art.

       

  • 12:30 - 12:45 pm EDT
               &
    11:30 - 11:45 pm EDT

    BeauCoup: Answering Many Network Traffic Queries, One Memory Update at a Time

    Xiaoqi Chen, Shir Landau-Feibish, Mark Braverman, Jennifer Rexford (Princeton University)

    • Abstract: Network administrators constantly monitor network traffic for congestion and attacks. They need to perform a large number of measurements on the traffic simultaneously, to detect different types of anomalies such as heavy hitters or super-spreaders. Existing techniques often focus on a single statistic (e.g., traffic volume) or traffic attribute (e.g., destination IP). However, performing numerous heterogeneous measurements within the constrained memory architecture of modern network devices poses significant challenges, due to the limited number of memory accesses allowed per packet. We propose BeauCoup, a system based on the coupon collector problem, that supports multiple distinct counting queries simultaneously while making only a small constant number of memory accesses per packet. We implement BeauCoup on PISA commodity programmable switches, satisfying the strict memory size and access constraints while using a moderate portion of other data-plane hardware resources. Evaluations show BeauCoup achieves the same accuracy as other sketch-based or sampling-based solutions using 4x fewer memory access.

       

  • 12:45 - 1:00 pm EDT
               &
    11:45 - 11:59 pm EDT

    A Computational Approach to Packet Classification

    Alon Rashelbach, Ori Rottenstreich, Mark Silberstein (Technion)

    • Abstract: Multi-field packet classification is a crucial component in modern software-defined data center networks. To achieve high throughput and low latency, state-of-the-art algorithms strive to fit the rule lookup data structures into on-die caches; however, they do not scale well with the number of rules.

      We present a novel approach, NuevoMatch, which improves the memory scaling of existing methods. A new data structure, Range Query Recursive Model Index (RQ-RMI), is the key component that enables NuevoMatch to replace most of the accesses to main memory with model inference computations. We describe an efficient training algorithm that guarantees the correctness of the RQ-RMI-based classification. The use of RQ-RMI allows the rules to be compressed into model weights that fit into the hardware cache. Further, it takes advantage of the growing support for fast neural network processing in modern CPUs, such as wide vector instructions, achieving a rate of tens of nanoseconds per lookup.

      Our evaluation using 500K multi-field rules from the standard ClassBench benchmark shows a geometric mean compression factor of 4.9x, 8x, and 82x, and average performance improvement of 2.4x, 2.6x, and 1.6x in throughput compared to CutSplit, NeuroCuts, and TupleMerge, all state-of-the-art algorithms.

       

  • 1:05 - 1:40 pm EDT  &  12:05 - 12:40 am EDT      Panel     (happening in parallel with the Sponsors/Job Event, see below)

    Session chair(s): Nick Feamster
    Go to Slack channel
  • 1:05 - 1:40 pm EDT
               &
    12:05 - 12:40 am EDT

    A Conversation On Privacy

    Speakers: Dave Choffnes (Northeastern University), Dave Levin (University of Maryland), Franzi Roesner (University of Washington), Stefan Savage (UC San Diego)

  • 1:05 - 1:40 pm EDT SIGCOMM Sponsors/Job Event (Go to Slack channel)

  • 1:45 - 2:45 pm EDT  &  12:45 - 1:45 am EDT      Technical Session 3: Routing: Take Me via Scenic Routes

    Session chairs: Dave Levin (western hemisphere) & Tim Griffin (eastern hemisphere)
    Go to Slack channel
  • 1:45 - 2:00 pm EDT
               &
    12:45 - 1:00 am EDT

    Concurrent Entanglement Routing for Quantum Networks: Model and Designs

    Shouqian Shi, Chen Qian (University of California, Santa Cruz)

    • Abstract: Quantum entanglement enables important computing applications such as quantum key distribution. Based on quantum entanglement, quantum networks are built to provide long-distance secret sharing between two remote communication parties. Establishing a multi-hop quantum entanglement exhibits a high failure rate, and existing quantum networks rely on trusted repeater nodes to transmit quantum bits. However, when the scale of a quantum network increases, it requires end-to-end multi-hop quantum entanglements in order to deliver secret bits without letting the repeaters know the secret bits. This work focuses on the entanglement routing problem, whose objective is to build long-distance entanglements via untrusted repeaters for concurrent source-destination pairs through multiple hops. Different from existing work that analyzes the traditional routing techniques on special network topologies, we present a comprehensive entanglement routing model that reflects the differences between quantum networks and classical networks as well as a new entanglement routing algorithm that utilizes the unique properties of quantum networks. Evaluation results show that the proposed algorithm Q-CAST increases the number of successful long-distance entanglements by a big margin compared to other methods. The model and simulator developed by this work may encourage more network researchers to study the entanglement routing problem.

       

  • 2:00 - 2:15 pm EDT
               &
    1:00 - 1:15 am EDT

    A Public Option for the Core

    Yotam Harchol (EPFL); Dirk Bergemann (Yale); Nick Feamster (University of Chicago); Eric Friedman (ICSI and UC Berkeley); Arvind Krishnamurthy (University of Washington); Aurojit Panda (NYU); Sylvia Ratnasamy (UC Berkeley); Michael Schapira (Hebrew University of Jerusalem); Scott Shenker (UC Berkeley)

    • Abstract: This paper is focused not on the Internet architecture - as defined by layering, the narrow waist of IP, and other core design principles - but on the Internet infrastructure, as embodied in the technologies and organizations that provide Internet service. In this paper we discuss both the challenges and the opportunities that make this an auspicious time to revisit how we might best structure the Internet's infrastructure. Currently, the tasks of transit-between-domains and last-mile-delivery are jointly handled by a set of ISPs who interconnect through BGP. In this paper we propose cleanly separating these two tasks. For transit, we propose the creation of a "public option" for the Internet's core backbone. This public option core, which complements rather than replaces the backbones used by large-scale ISPs, would (i) run an open market for backbone bandwidth so it could leverage links offered by third-parties, and (ii) structure its terms-of-service to enforce network neutrality so as to encourage competition and reduce the advantage of large incumbents.

       

  • 2:15 - 2:30 pm EDT
               &
    1:15 - 1.30 am EDT

    PCF: Provably Resilient Flexible Routing

    Chuan Jiang, Sanjay Rao, Mohit Tawarmalani (Purdue University)

    • Abstract: Recently, traffic engineering mechanisms have been developed that guarantee that a network (cloud provider WAN, or ISP) does not experience congestion under failures. In this paper, we show that existing congestion-free mechanisms, notably FFC, achieve performance far short of the network's intrinsic capability. We propose PCF, a set of novel congestion-free mechanisms to bridge this gap. PCF achieves these goals by better modeling network structure, and by carefully enhancing the flexibility of network response while ensuring that the performance under failures can be tractably modeled. All of PCF's schemes involve relatively light-weight operations on failures, and many of them can be realized using a local proportional routing scheme similar to FFC. We show PCF's effectiveness through formal theoretical results, and empirical experiments over 21 Internet topologies. PCF's schemes provably out-perform FFC, and in practice, can sustain higher throughput than FFC by a factor of 1.11X to 1.5X on average across the topologies, while providing a benefit of 2.6X in some cases.

       

  • 2:30 - 2:45 pm EDT
               &
    1:30 - 1:45 am EDT

    Routing on Multiple Optimality Criteria

    João Luís Sobrinho, Miguel Alves Ferreira (Instituto de Telecomunicações, Instituto Superior Técnico, Universidade de Lisboa)

    • Abstract: Standard vectoring protocols, such as EIGRP, BGP, DSDV, or Babel, only route on optimal paths when the total order on path attributes that substantiates optimality is consistent with the extension operation that calculates path attributes from link attributes, leaving out many optimality criteria of practical interest. We present a solution to this problem and, more generally, to the problem of routing on multiple optimality criteria. A key idea is the derivation of a partial order on path attributes that is consistent with the extension operation and respects every optimality criterion of a designated collection of such criteria. We design new vectoring protocols that compute on partial orders, with every node capable of electing multiple attributes per destination rather than a single attribute as in standard vectoring protocols. Our evaluation over publicly available network topologies and attributes shows that the proposed protocols converge fast and enable optimal path routing concurrently for many optimality criteria with only a few elected attributes at each node per destination. We further show how predicating computations on partial orders allows incorporation of service chain constraints on optimal path routing.

       

  • 2:45 - 3:45 pm EDT  &  1:45 - 2:45 am EDT      Technical Session 4: Verification: Are you doing what I think you're doing?

    Session chairs: Minlan Yu (western hemisphere) & Nate Foster (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Verification
  • 2:45 - 3:00 pm EDT
               &
    1:45 - 2:00 am EDT

    bf4: towards bug-free P4 programs

    Dragos Dumitrescu, Radu Stoenescu, Lorina Negreanu, Costin Raiciu (University Politehnica of Bucharest)

    • Abstract: Recent verification work has made advances in finding bugs in P4 programs before deployment, but it requires that the programmer specifies table rules that are possible at runtime[32, 24, 27]. This imposes a specification burden on the programmer, while at the same time failing to guarantee that bugs will not be inserted at runtime by faulty controllers.

      We present bf4, a novel verification approach for P4 programs that uses a mix of static verification, code changes and runtime checks to ensure that the deployed P4 program is bug free. To achieve this, bf4 uses static analysis to find all possible bugs in the P4 program; for each possible bug, bf4 attempts to find predicates that, when applied to table rules inserted by the controller, make that bug unreachable. If such predicates do not exist, bf4 can change the P4 code and re-run the procedure above.

      We applied bf4 to a wide range of P4 programs; for all these, bf4 is able to generate controller assertions and propose fixes that guarantee no controller-induced bug is reachable. At runtime, bf4 checks that the controller does not insert faulty rules; when it does, it throws an exception which helps troubleshoot the bug.

       

  • 3:00 - 3:15 pm EDT
               &
    2:00 - 2:15 am EDT

    GRoot: Proactive Verification of DNS Configurations

    Siva Kesava Reddy Kakarla (UCLA); Ryan Beckett, Behnaz Arzani (Microsoft Research); Todd Millstein (UCLA / Intentionet); George Varghese (UCLA)

    • Abstract: The Domain Name System (DNS) plays a vital role in today's Internet but relies on complex distributed management of records. DNS misconfiguration related outages have rendered popular services like GitHub, HBO, LinkedIn, and Azure inaccessible for extended periods. This paper introduces GRoot, the first verifier that performs static analysis of DNS configuration files, enabling proactive and exhaustive checking for common DNS bugs; by contrast, existing solutions are reactive and incomplete. GRoot uses a new, fast verification algorithm based on generating and enumerating DNS query equivalence classes. GRoot symbolically executes the set of queries in each equivalence class to efficiently find (or prove the absence of) any bugs such as rewrite loops. To prove the correctness of our approach, we develop a formal semantic model of DNS resolution. Applied to the configuration files from a campus network with over a hundred thousand records, GRoot revealed 109 bugs within seconds. When applied to internal zone files consisting of over 3.5 million records from a large infrastructure service provider, GRoot revealed around 160k issues of blackholing, initiating a cleanup. Finally, on a synthetic dataset with over 65 million real records, we find GRoot can scale to networks with tens of millions of records.

       

  • 3:15 - 3:30 pm EDT
               &
    2:15 - 2:30 am EDT

    Probabilistic Verification of Network Configurations

    Samuel Steffen, Timon Gehr, Petar Tsankov, Laurent Vanbever, Martin Vechev (ETH Zürich)

    • Abstract: Not all important network properties need to be enforced all the time. Often, what matters instead is the fraction of time / probability these properties hold. Computing the probability of a property in a network relying on complex inter-dependent routing protocols is challenging and requires determining all failure scenarios for which the property is violated. Doing so at scale and accurately goes beyond the capabilities of current network analyzers.

      In this paper, we introduce NetDice, the first scalable and accurate probabilistic network configuration analyzer supporting BGP, OSPF, ECMP, and static routes. Our key contribution is an inference algorithm to efficiently explore the space of failure scenarios. More specifically, given a network configuration and a property φ, our algorithm automatically identifies a set of links whose failure is provably guaranteed not to change whether φ holds. By pruning these failure scenarios, NetDice manages to accurately approximate P(φ). NetDice supports practical properties and expressive failure models including correlated link failures.

      We implement NetDice and evaluate it on realistic configurations. NetDice is practical: it can precisely verify probabilistic properties in few minutes, even in large networks.

       

  • 3:30 - 3:45 pm EDT
               &
    2:30 - 2:45 am EDT

    Accuracy, Scalability, Coverage – A Practical Configuration Verifier on a Global WAN

    Fangdan Ye (Tsinghua University); Da Yu (Brown University); Ennan Zhai, Hongqiang Harry Liu (Alibaba Group); Bingchuan Tian (Nanjing University); Qiaobo Ye, Chunsheng Wang, Xin Wu, Tianchen Guo, Cheng Jin, Duncheng She, Qing Ma, Biao Cheng, Hui Xu, Ming Zhang (Alibaba Group); Zhiliang Wang (Tsinghua University); Rodrigo Fonseca (Brown University)

    • Abstract: This paper presents Hoyan-- the first reported large scale deployment of configuration verification in a global-scale wide area network (WAN). Hoyan has been running in production for more than two years and is currently used for all critical configuration auditing and updates on the WAN. We highlight our innovative designs and real-life experience to make Hoyan accurate and scalable in practice. For accuracy under the inconsistencies of devices' vendor-specific behaviors (VSBs), Hoyan continuously discovers the flaws in device behavior models, thus aiding the operators in fixing the models. For scalability to verify our global WAN, Hoyan introduces a "global-simulation & local formal-modeling" strategy to model uncertainties in small scales and perform aggressive pruning of possibilities during the protocol simulations. Hoyan achieves near-100% verification accuracy after it detected and fixed O(10) VSBs on our WAN. Hoyan has prevented many potential service failures resulting from misconfiguration and reduced the failure rate of updates of our WAN by more than half in 2019.

       

  • 3:45 - 4:30 pm EDT  &  2:45 - 3:30 am EDT      Technical Session 5: Let's watch some videos

    Session chairs: Ganesh Ananthanarayanan (western hemisphere) & Dongsu Han (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Video+ML
  • 3:45 - 4:00 pm EDT
               &
    2:45 - 3:00 am EDT

    Neural-Enhanced Live Streaming: Improving Live Video Ingest via Online Learning

    Jaehong Kim, Youngmok Jung, Hyunho Yeo, Juncheol Ye, Dongsu Han (KAIST)

    • Abstract: Live video accounts for a significant volume of today's Internet video. Despite a large number of efforts to enhance user quality of experience (QoE) both at the ingest and distribution side of live video, the fundamental limitations are that streamer's upstream bandwidth and computational capacity limit the quality of experience of thousands of viewers.

      To overcome this limitation, we design LiveNAS, a new live video ingest framework that enhances the origin stream's quality by leveraging computation at ingest servers. Our ingest server applies neural super-resolution on the original stream, while imposing minimal overhead on ingest clients. LiveNAS employs online learning to maximize the quality gain and dynamically adjusts the resource use to the real-time quality improvement. LiveNAS delivers high-quality live streams up to 4K resolution, outperforming WebRTC by 1.96 dB on average in Peak-Signal-to-Noise-Ratio on real video streams and network traces, which leads to 12%-69% QoE improvement for live stream viewers.

       

  • 4:00 - 4:15 pm EDT
               &
    3:00 - 3:15 am EDT

    Server-Driven Video Streaming for Deep Learning Inference

    Kuntai Du, Ahsan Pervaiz, Xin Yuan (University of Chicago); Aakanksha Chowdhery (Google); Qizheng Zhang, Henry Hoffmann, Junchen Jiang (University of Chicago)

    • Abstract: Video streaming is crucial for AI applications that gather videos from sources to servers for inference by deep neural nets (DNNs). Unlike traditional video streaming that optimizes visual quality, this new type of video streaming permits aggressive compression/pruning of pixels not relevant to achieving high DNN inference accuracy. However, much of this potential is left unrealized, because current video streaming protocols are driven by the video source (camera) where the compute is rather limited. We advocate that the video streaming protocol should be driven by real-time feedback from the server-side DNN. Our insight is two-fold: (1) server-side DNN has more context about the pixels that maximize its inference accuracy; and (2) the DNN's output contains rich information useful to guide video streaming. We present DDS (DNN-Driven Streaming), a concrete design of this approach. DDS continuously sends a low-quality video stream to the server; the server runs the DNN to determine where to re-send with higher quality to increase the inference accuracy. We find that compared to several recent baselines on multiple video genres and vision tasks, DDS maintains higher accuracy while reducing bandwidth usage by upto 59% or improves accuracy by upto 9% with no additional bandwidth usage.

       

  • 4:15 - 4:30 pm EDT
               &
    3:15 - 3:30 am EDT

    Reducto: On-Camera Filtering for Resource-Efficient Real-Time Video Analytics

    Yuanqi Li, Arthi Padmanabhan, Pengzhan Zhao, Yufei Wang, Guoqing Harry Xu, Ravi Netravali (UCLA)

    • Abstract: To cope with the high resource (network and compute) demands of real-time video analytics pipelines, recent systems have relied on frame filtering. However, filtering has typically been done with neural networks running on edge/backend servers that are expensive to operate. This paper investigates on-camera filtering, which moves filtering to the beginning of the pipeline. Unfortunately, we find that commodity cameras have limited compute resources that only permit filtering via frame differencing based on low-level video features. Used incorrectly, such techniques can lead to unacceptable drops in query accuracy. To overcome this, we built Reducto, a system that dynamically adapts filtering decisions according to the time-varying correlation between feature type, filtering threshold, query accuracy, and video content. Experiments with a variety of videos and queries show that Reducto achieves significant (51-97% of frames) filtering benefits, while consistently meeting the desired accuracy.

       

  • 4:30 - 5:30 pm EDT      Posters and Demos Session I

    Go to Slack channel
  • 4:30 - 5:30 pm EDT Posters and Demos

  • 5:30 - 6:30 pm EDT   &   3:30 - 4:30 am EDT Pictionary (Go to Slack channel)

  • Wednesday, August 12, 2020 EDT

  • 9:45 - 10:45 am EDT  &  8:45 - 9:45 pm EDT      Keynote 2

    Go to Slack channel
  • 9:45 - 10:45 am EDT
               &
    8:45 - 9:45 pm EDT

    Learning the Art and Science in Internet Protocol Designs

    Speakers: Lixia Zhang (UCLA)

    • The annual SIGCOMM Award will be presented to Lixia Zhang for her many insights into data network architectures and the interactions between network components.

       

  • 10:45 - 11:59 am EDT  &  9:45 - 11:00 pm EDT      Technical Session 6: Congestion Control: Now now, not so fast

    Session chairs: Rachit Agarwal (western hemisphere) & Radhika Mittal (eastern hemisphere)
    Go to Slack channel
  • 10:45 - 11:00 am EDT
               &
    9:45 - 10:00 pm EDT

    PBE-CC: Congestion Control via Endpoint-Centric, Physical-Layer Bandwidth Measurements

    Yaxiong Xie, Fan Yi, Kyle Jamieson (Princeton University)

    • Abstract: Cellular networks are becoming ever more sophisticated and overcrowded, imposing the most delay, jitter, and throughput damage to end-to-end network flows in today's internet. We therefore argue for fine-grained mobile endpoint-based wireless measurements to inform a precise congestion control algorithm through a well-defined API to the mobile's cellular physical layer. Our proposed congestion control algorithm is based on Physical-Layer Bandwidth measurements taken at the Endpoint (PBE-CC), and captures the latest 5G New Radio innovations that increase wireless capacity, yet create abrupt rises and falls in available wireless capacity that the PBE-CC sender can react to precisely and rapidly. We implement a proof-of-concept prototype of the PBE measurement module on software-defined radios and the PBE sender and receiver in C. An extensive performance evaluation compares PBE-CC head to head against the cellular-aware and wireless-oblivious congestion control protocols proposed in the research community and in deployment, in mobile and static mobile scenarios, and over busy and idle networks. Results show 6.3% higher average throughput than BBR, while simultaneously reducing 95th percentile delay by 1.8x.

       

  • 11:00 - 11:15 am EDT
               &
    10:00 - 10:15 pm EDT

    PCC Proteus: Scavenger Transport And Beyond

    Tong Meng (UIUC); Neta Rozen Schiff (Hebrew University of Jerusalem); Brighten Godfrey (UIUC and VMware); Michael Schapira (Hebrew University of Jerusalem)

    • Abstract: Many Internet applications need high bandwidth but are not time sensitive. This motivates a congestion control "scavenger" that voluntarily yields to higher-priority applications, thus improving overall user experience. However, the existing scavenger protocol, LEDBAT, often fails to yield, has performance shortcomings, and requires a codebase separate from other transport protocols.

      We present PCC Proteus, a new congestion controller that can behave as an effective scavenger or primary protocol. Proteus incorporates several novel ideas to ensure that it yields to primary flows while still obtaining high performance, including using latency deviation as a signal of competition, and techniques for noise tolerance in dynamic environments. By extending the existing PCC utility framework, Proteus also allows applications to specify a flexible utility function that, in addition to scavenger and primary modes, allows choice of hybrid modes between the two, better capturing application needs. Extensive emulation and real-world evaluation show that Proteus is capable of both being a much more effective scavenger than LEDBAT, and of acting as a high performance primary protocol. Application-level experiments show Proteus significantly improves page load time and DASH video delivery, and its hybrid mode significantly reduces rebuffering in a bandwidth-constrained environment.

       

  • 11:15 - 11:30 am EDT
               &
    10:15 - 10:30 pm EDT

    Annulus: A Dual Congestion Control Loop for Datacenter and WAN Traffic Aggregates

    Ahmed Saeed (MIT); Varun Gupta (AT&T Labs Research); Prateesh Goyal (MIT); Milad Sharif (Barefoot Networks); Rong Pan (Cisco Systems); Mostafa Ammar, Ellen Zegura (Georgia Institute of Technology); Keon Jang (MPI-SWS); Mohammad Alizadeh (MIT); Abdul Kabbani, Amin Vahdat (Google)

    • Abstract: Cloud services are deployed in datacenters connected though high-bandwidth Wide Area Networks (WANs). We find that WAN traffic negatively impacts the performance of datacenter traffic, increasing tail latency by 2.5x, despite its small bandwidth demand. This behavior is caused by the long round-trip time (RTT) for WAN traffic, combined with limited buffering in datacenter switches. The long WAN RTT forces datacenter traffic to take the full burden of reacting to congestion. Furthermore, datacenter traffic changes on a faster time-scale than the WAN RTT, making it difficult for WAN congestion control to estimate available bandwidth accurately.

      We present Annulus, a congestion control scheme that relies on two control loops to address these challenges. One control loop leverages existing congestion control algorithms for bottlenecks where there is only one type of traffic (i.e., WAN or datacenter). The other loop handles bottlenecks shared between WAN and datacenter traffic near the traffic source, using direct feedback from the bottleneck. We implement Annulus on a testbed and in simulation. Compared to baselines using BBR for WAN congestion control and DCTCP or DCQCN for datacenter congestion control, Annulus increases bottleneck utilization by 10% and lowers datacenter flow completion time by 1.3-3.5x.

       

  • 11:30 - 11:45 am EDT
               &
    10:30 - 10:45 pm EDT

    Swift: Delay is Simple and Effective for Congestion Control in the Datacenter

    Gautam Kumar, Nandita Dukkipati (Google); Keon Jang (MPI-SWS); Hassan M. G. Wassel, Xian Wu, Behnam Montazeri, Yaogong Wang, Kevin Springborn, Christopher Alfeld, Michael Ryan, David Wetherall, Amin Vahdat (Google)

    • Abstract: We report on experiences with Swift congestion control in Google datacenters. Swift targets an end-to-end delay by using AIMD control, with pacing under extreme congestion. With accurate RTT measurement and care in reasoning about delay targets, we find this design is a foundation for excellent performance when network distances are well-known. Importantly, its simplicity helps us to meet operational challenges. Delay is easy to decompose into fabric and host components to separate concerns, and effortless to deploy and maintain as a congestion signal while the datacenter evolves. In large-scale testbed experiments, Swift delivers a tail latency of <50μs for short RPCs, with near-zero packet drops, while sustaining ~100Gbps throughput per server. This is a tail of <3x the minimal latency at a load close to 100%. In production use in many different clusters, Swift achieves consistently low tail completion times for short RPCs, while providing high throughput for long RPCs. It has loss rates that are at least 10x lower than a DCTCP protocol, and handles O(10k) incasts that sharply degrade with DCTCP.

       

  • 11:45 - 11:59 am EDT
               &
    10:45 - 11:00 pm EDT

    Classic Meets Modern: a Pragmatic Learning-Based Congestion Control for the Internet

    Soheil Abbasloo, Chen-Yu Yen, H. Jonathan Chao (NYU)

    • Abstract: These days, taking the revolutionary approach of using clean-slate learning-based designs to completely replace the classic congestion control schemes for the Internet is gaining popularity. However, we argue that current clean-slate learning-based techniques bring practical issues and concerns such as overhead, convergence issues, and low performance over unseen network conditions to the table. To address these issues, we take a pragmatic and evolutionary approach combining classic congestion control strategies and advanced modern deep reinforcement learning (DRL) techniques and introduce a novel hybrid congestion control for the Internet named Orca1. Through extensive experiments done over global testbeds on the Internet and various locally emulated network conditions, we demonstrate that Orca is adaptive and achieves consistent high performance in different network conditions, while it can significantly alleviate the issues and problems of its clean-slate learning-based counterparts.

       

  • 12:00 - 1:00 pm EDT  &  11:00 - 11:59 pm EDT      Technical Session 7: What is Switch Programmability Good For?

    Session chairs: Nate Foster (western hemisphere) & Kate Lin (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Programmable switches     Network Function Virtualization     Telemetry
  • 12:00 - 12:15 pm EDT
               &
    11:00 - 11:15 pm EDT

    NetLock: Fast, Centralized Lock Management Using Programmable Switches

    Zhuolong Yu (Johns Hopkins University); Yiwen Zhang (University of Michigan); Vladimir Braverman (Johns Hopkins University); Mosharaf Chowdhury (University of Michigan); Xin Jin (Johns Hopkins University)

    • Abstract: Lock managers are widely used by distributed systems. Traditional centralized lock managers can easily support policies between multiple users using global knowledge, but they suffer from low performance. In contrast, emerging decentralized approaches are faster but cannot provide flexible policy support. Furthermore, performance in both cases is limited by the server capability.

      We present NetLock, a new centralized lock manager that co-designs servers and network switches to achieve high performance without sacrificing flexibility in policy support. The key idea of NetLock is to exploit the capability of emerging programmable switches to directly process lock requests in the switch data plane. Due to the limited switch memory, we design a memory management mechanism to seamlessly integrate the switch and server memory. To realize the locking functionality in the switch, we design a custom data plane module that efficiently pools multiple register arrays together to maximize memory utilization We have implemented a NetLock prototype with a Barefoot Tofino switch and a cluster of commodity servers. Evaluation results show that NetLock improves the throughput by 14.0-18.4x, and reduces the average and 99% latency by 4.7-20.3x and 10.4-18.7x over DSLR, a state-of-the-art RDMA-based solution, while providing flexible policy support.

       

  • 12:15 - 12:30 pm EDT
               &
    11:15 - 11:30 pm EDT

    TEA: Enabling State-Intensive Network Functions on Programmable Switches

    Daehyeok Kim (Carnegie Mellon University and Microsoft Research); Zaoxing Liu (Carnegie Mellon University and Boston University); Yibo Zhu (ByteDance Inc.); Changhoon Kim, Jeongkeun Lee (Intel, Barefoot Switch Division); Vyas Sekar, Srinivasan Seshan (Carnegie Mellon University)

    • Abstract: Programmable switches have been touted as an attractive alternative for deploying network functions (NFs) such as network address translators (NATs), load balancers, and firewalls. However, their limited memory capacity has been a major stumbling block that has stymied their adoption for supporting state-intensive NFs such as cloud-scale NATs and load balancers that maintain millions of flow-table entries. In this paper, we explore a new approach that leverages DRAM on servers available in typical NFV clusters. Our new system architecture, called TEA (Table Extension Architecture), provides a virtual table abstraction that allows NFs on programmable switches to look up large virtual tables built on external DRAM. Our approach enables switch ASICs to access external DRAM purely in the data plane without involving CPUs on servers. We address key design and implementation challenges in realizing this idea. We demonstrate its feasibility and practicality with our implementation on a Tofino-based programmable switch. Our evaluation shows that NFs built with TEA can look up table entries on external DRAM with low and predictable latency (1.8-2.2 μs) and the lookup throughput can be linearly scaled with additional servers (138 million lookups per seconds with 8 servers).

       

  • 12:30 - 12:45 pm EDT
               &
    11:30 - 11:45 pm EDT

    Flow Event Telemetry on Programmable Data Plane

    Yu Zhou (Alibaba Group and Tsinghua University); Chen Sun, Hongqiang Harry Liu, Rui Miao, Shi Bai, Bo Li, Zhilong Zheng, Lingjun Zhu, Zhen Shen, Yongqing Xi, Pengcheng Zhang, Dennis Cai, Ming Zhang (Alibaba Group); Mingwei Xu (Tsinghua University)

    • Abstract: Network performance anomalies (NPAs), e.g. long-tailed latency, bandwidth decline, etc., are increasingly crucial to cloud providers as applications are getting more sensitive to performance. The fundamental difficulty to quickly mitigate NPAs lies in the limitations of state-of-the-art network monitoring solutions --- coarse-grained counters, active probing, or packet telemetry either cannot provide enough insights on flows or incur too much overhead. This paper presents NetSeer, a flow event telemetry (FET) monitor which aims to discover and record all performance-critical data plane events, e.g. packet drops, congestion, path change, and packet pause. NetSeer is efficiently realized on the programmable data plane. It has a high coverage on flow events including inter-switch packet drop/corruption which is critical but also challenging to retrieve the original flow information, with novel intra- and inter-switch event detection algorithms running on data plane; NetSeer also achieves high scalability and accuracy with innovative designs of event aggregation, information compression, and message batching that mainly run on data plane, using switch CPU as complement. NetSeer has been implemented on commodity programmable switches and NICs. With real case studies and extensive experiments, we show NetSeer can reduce NPA mitigation time by 61%-99% with only 0.01% overhead of monitoring traffic.

       

  • 12:45 - 1:00 pm EDT
               &
    11:45 - 11:59 pm EDT

    Mantis: Reactive Programmable Switches

    Liangcheng Yu (University of Pennsylvania); John Sonchack (Princeton University); Vincent Liu (University of Pennsylvania)

    • Abstract: For modern data center switches, the ability to---with minimum latency and maximum flexibility--- react to current network conditions is important for managing increasingly dynamic networks. The traditional approach to implementing this type of behavior is through a control plane that is orders of magnitude slower than the speed at which typical data center congestion events occur. More recent alternatives like programmable switches can remember statistics about passing traffic and adjust behavior accordingly, but unfortunately, their capabilities severely limit what can be done.

      In this paper, we present Mantis, a framework for implementing fine-grained reactive behavior on today's programmable switches with the help of a specialized reactive control plane architecture. Mantis is, thus, a combination of language for specifying dynamic components of packet processing and an optimized, general, and safe control loop for implementing them. Mantis provides a simple-to-reason-about set of abstractions for users, and the Mantis control plane can react to changes in the network in 10s of μs.

       

  • 1:05 - 1:40 pm EDT  &  12:05 - 12:40 am EDT      Panel     (happening in parallel with the SIGCOMM Community Meeting, see below)

    Session chair(s): Ellen Zegura
    Go to Slack channel
  • 1:05 - 1:40 pm EDT
               &
    12:05 - 12:40 am EDT

    A Conversation on Networking for the Social Good

    Speakers: Martin Casado (MuralNet), Kurtis Heimerl (University of Washington), Leandro Navarro (Politecnica de Catalunya), Ellen Zegura (Georgia Tech)

  • 1:05 - 1:40 pm EDT   &   12:05 - 12:40 am EDT SIGCOMM Community Meeting

  • 1:45 - 2:45 pm EDT  &  12:45 - 1:45 am EDT      Technical Session 8: Build new data center services but don't forget to debug current ones

    Session chairs: Manya Ghobadi (western hemisphere) & Paolo Costa (eastern hemisphere)
    Go to Slack channel
  • 1:45 - 2:00 pm EDT
               &
    12:45 - 1:00 am EDT

    Aeolus: A Building Block for Proactive Transport in Datacenters

    Shuihai Hu (HKUST and Clustar); Wei Bai (HKUST and Microsoft Research); Gaoxiong Zeng, Zilong Wang, Baochen Qiao, Kai Chen (HKUST); Kun Tan (Huawei); Yi Wang (Peng Cheng Lab)

    • Abstract: As datacenter network bandwidth keeps growing, proactive transport becomes attractive, where bandwidth is proactively allocated as "credits" to senders who then can send "scheduled packets" at a right rate to ensure high link utilization, low latency, and zero packet loss. While promising, a fundamental challenge is that proactive transport requires at least one-RTT for credits to be computed and delivered. In this paper, we show such one-RTT "pre-credit" phase could carry a substantial amount of flows at high link-speeds, but none of existing proactive solutions treats it appropriately. We present Aeolus, a solution focusing on "pre-credit" packet transmission as a building block for proactive transports. Aeolus contains unconventional design principles such as scheduled-packet-first (SPF) that de-prioritizes the first-RTT packets, instead of prioritizing them as prior work. It further exploits the preserved, deterministic nature of proactive transport as a means to recover lost first-RTT packets efficiently. We have integrated Aeolus into ExpressPass[14], NDP[18] and Homa[29], and shown, through both implementation and simulations, that the Aeolus-enhanced solutions deliver signiicant performance or deployability advantages. For example, it improves the average FCT of ExpressPass by 56%, cuts the tail FCT of Homa by 20x, while achieving similar performance as NDP without switch modifications.

       

  • 2:00 - 2:15 pm EDT
               &
    1:00 - 1:15 am EDT

    MasQ: RDMA for Virtual Private Cloud

    Zhiqiang He (University of Science and Technology of China; Huawei Technologies Co., Ltd); Dongyang Wang, Binzhang Fu, Kun Tan (Huawei Technologies Co., Ltd); Bei Hua (University of Science and Technology of China); Zhi-Li Zhang (University of Minnesota); Kai Zheng (Huawei Technologies Co., Ltd)

    • Abstract: RDMA communication in virtual private cloud (VPC) networks is still a challenging job due to the difficulty in fulfilling all virtualization requirements without sacrificing RDMA communication performance. To address this problem, this paper proposes a software-defined solution, namely, MasQ, which is short for "queue masquerade". The core insight of MasQ is that all RDMA communications should associate with at least one queue pair (QP). Thus, the requirements of virtualization, such as network isolation and the application of security rules, can be easily fulfilled if QP's behavior is properly defined. In particular, MasQ exploits the virtio-based paravirtualization technique to realize the control path. Moreover, to avoid performance overhead, MasQ leaves all data path operations, such as sending and receiving, to the hardware. We have implemented MasQ in the OpenFabrics Enterprise Distribution (OFED) framework and proved its scalability and performance efficiency by evaluating it against typical applications. The results demonstrate that MasQ achieves almost the same performance as bare-metal RDMA for data communication.

       

  • 2:15 - 2:30 pm EDT
               &
    1:15 - 1:30 am EDT

    VTrace: Automatic Diagnostic System for Persistent Packet Loss in Cloud-Scale Overlay Network

    Chongrong Fang, Haoyu Liu (Zhejiang University); Mao Miao, Jie Ye, Lei Wang, Wansheng Zhang, Daxiang Kang, Biao Lyv (Alibaba Group); Peng Cheng, Jiming Chen (Zhejiang University)

    • Abstract: Persistent packet loss in the cloud-scale overlay network severely compromises tenant experiences. Cloud providers are keen to automatically and quickly determine the root cause of such problems. However, existing work is either designed for the physical network or insufficient to present the concrete reason of packet loss. In this paper, we propose to record and analyze the on-site forwarding condition of packets during packet-level tracing. The cloud-scale overlay network presents great challenges to achieve this goal with its high network complexity, multi-tenant nature, and diversity of root causes. To address these challenges, we present VTrace, an automatic diagnostic system for persistent packet loss over the cloud-scale overlay network. Utilizing the "fast path-slow path" structure of virtual forwarding devices (VFDs), e.g., vSwitches, VTrace installs several "coloring, matching and logging" rules in VFDs to selectively track the packets of interest and inspect them in depth. The detailed forwarding situation at each hop is logged and then assembled to perform analysis with an efficient path reconstruction scheme. Experiments are conducted to demonstrate VTrace's low overhead and quick responsiveness. We share experiences of how VTrace efficiently resolves persistent packet loss issues after deploying it in Alibaba Cloud for over 20 months.

       

  • 2:30 - 2:45 pm EDT
               &
    1:30 - 1:45 am EDT

    Scouts: Improving the Diagnosis Process Through Domain-customized Incident Routing

    Jiaqi Gao (Harvard University); Nofel Yaseen (University of Pennsylvania); Robert MacDavid (Princeton University); Felipe Vieira Frujeri (Microsoft Research); Vincent Liu (University of Pennsylvania); Ricardo Bianchini (Microsoft Research); Ramaswamy Aditya, Xiaohang Wang, Henry Lee, David Maltz (Microsoft); Minlan Yu (Harvard University); Behnaz Arzani (Microsoft Research)

    • Abstract: Incident routing is critical for maintaining service level objectives in the cloud: the time-to-diagnosis can increase by 10x due to mis-routings. Properly routing incidents is challenging because of the complexity of today's data center (DC) applications and their dependencies. For instance, an application running on a VM might rely on a functioning host-server, remote-storage service, and virtual and physical network components. It is hard for any one team, rule-based system, or even machine learning solution to fully learn the complexity and solve the incident routing problem. We propose a different approach using per-team Scouts. Each teams' Scout acts as its gate-keeper --- it routes relevant incidents to the team and routes-away unrelated ones. We solve the problem through a collection of these Scouts. Our PhyNet Scout alone --- currently deployed in production --- reduces the time-to-mitigation of 65% of mis-routed incidents in our dataset.

       

  • 2:45 - 3:45 pm EDT  &  1:45 - 2:45 am EDT      Technical Session 9: Backscatter: Look Ma, No Batteries

    Session chairs: Deepak Vasisht (western hemisphere) & Lili Qiu (eastern hemisphere)
    Go to Slack channel
  • 2:45 - 3:00 pm EDT
               &
    1:45 - 2:00 am EDT

    Turboboosting Visible Light Backscatter Communication

    Yue Wu, Purui Wang, Kenuo Xu, Lilei Feng, Chenren Xu (Peking University)

    • Abstract: Visible light backscatter communication (VLBC) presents an emerging low power IoT connectivity solution with spatial reuse and interference immunity advantages over RF-based (backscatter) technologies. State-of-the-art VLBC systems employ COTS LCD shutter as optical modulator, whose slow response fundamentally throttles its data rate to sub-Kbps, and limits its deployment at scale for use cases where higher rate and/or low latency is a necessity.

      We design and implement RetroTurbo, a VLBC system dedicated for turboboosting data rate. At the heart of RetroTurbo design is a pair of novel modulation schemes, namely delayed superimposition modulation (DSM) and polarization-based QAM (PQAM), to push the rate limit by strategically coordinating the state of a liquid crystal modulator (LCM) pixel array in time and polarization domains. Specifically, DSM ensures we fully exploit the available SNR for high order modulation in the LCM-imposed nonlinear channel; PQAM is based on polarized light communication that creates a QAM design in polarization domain with flexible angular misalignment between two ends. A real-time near-optimal demodulation algorithm is designed to ensure system's robustness to heterogeneous signal distortion. Based on our prototyped system, RetroTurbo demonstrates 32x and 128x rate gain via experiments and emulation respectively in practical real-world indoor setting.

       

  • 3:00 - 3:15 pm EDT
               &
    2:00 - 2:15 am EDT

    Leveraging Ambient LTE Traffic for Ubiquitous Passive Communication

    Zicheng Chi, Xin Liu, Wei Wang, Yao Yao, Ting Zhu (University of Maryland, Baltimore County)

    • Abstract: To support ubiquitous computing for various applications (such as smart health, smart homes, and smart cities), the communication system requires to be ubiquitously available, ultra-low-power, high throughput, and low-latency. A passive communication system such as backscatter is desirable. However, existing backscatter systems cannot achieve all of the above requirements. In this paper, we present the first LTE backscatter (LScatter) system that leverages the continuous LTE ambient traffic for ubiquitous, high throughput and low latency backscatter communication. Our design is motivated by our observation that LTE ambient traffic is continuous (v.s. bursty and intermittent WiFi/LoRa traffic), which makes LTE ambient traffic a perfect signal source of a backscatter system. Our design addresses practical issues such as time synchronization, phase modulation, as well as phase offset elimination. We extensively evaluated our design using a testbed of backscatter hardware and USRPs in multiple real-world scenarios. Results show that our LScatter's performance is consistently orders of magnitude better than WiFi backscatter in all the above scenarios. For example, LScatter's throughput is 13.63Mbps, which is 368 times higher than the latest ambient WiFi backscatter system [54]. We also demonstrate the effectiveness of our system using two real-world applications.

       

  • 3:15 - 3:30 pm EDT
               &
    2:15 - 2:30 am EDT

    WiTAG: Seamless WiFi Backscatter Communication

    Ali Abedi, Farzan Dehbashi, Mohammad Hossein Mazaheri (University of Waterloo); Omid Abari (UCLA); Tim Brecht (University of Waterloo)

    • Abstract: WiFi backscatter communication has the potential to enable battery-free sensors which can transmit data using a WiFi network. In order for WiFi backscatter systems to be practical they should be compatible with existing WiFi networks without any hardware or software modifications. Moreover, they should work with networks that use encryption. In this paper, we present WiTAG which achieves these requirements, making the implementation and deployment of WiFi backscatter communication more practical. In contrast with existing systems which utilize the physical layer for backscatter communication, we take a different approach by leveraging features of the MAC layer to communicate. WiTAG is designed to send data by selectively interfering with subframes (MPDUs) in an aggregated frame (A-MPDU). This enables standard compliant communication using modern, open or encrypted 802.11n and 802.11ac networks without requiring hardware or software modifications to any devices. We implement WiTAG using off-the-shelf components and evaluate its performance in line-of-sight and non-line-of-sight scenarios. We show that WiTAG achieves a throughput of up to 4 Kbps without impacting other devices in the network.

       

  • 3:30 - 3:45 pm EDT
               &
    2:30 - 2:45 am EDT

    Ultra-Wideband Underwater Backscatter via Piezoelectric Metamaterials

    Reza Ghaffarivardavagh, Sayed Saad Afzal, Osvy Rodriguez, Fadel Adib (MIT)

    • Abstract: We present the design, implementation, and evaluation of U2B, a technology that enables ultra-wideband backscatter in underwater environments. At the core of U2B's design is a novel metamaterialinspired transducer for underwater backscatter, and algorithms that enable self-interference cancellation and FDMA-based medium access control.

      We fabricated U2B nodes and tested them in a river across different weather conditions, including snow and rain. Our empirical evaluation demonstrates that U2B can achieve throughputs up to 20 kbps, an operational range up to 62 m, and can scale to networks with more than 10 nodes. In comparison to the state-of-the-art system for underwater backscatter, our design achieves 5x more throughput and 6x more communication range. Moreover, our evaluation represents the first experimental validation of underwater backscatter in the wild.

       

  • 3:45 - 4:30 pm EDT  &  2:45 - 3:30 am EDT      Technical Session 10: Best of CCR

    Session chairs: Steve Uhlig (western hemisphere) & Sergey Gorinsky (eastern hemisphere)
    Go to Slack channel
  • 3:45 - 4:00 pm EDT
               &
    2:45 - 3:00 am EDT

    An Open Platform to Teach How the Internet Practically Works

    Thomas Holterbach (ETH Zurich),Tobias Bühler (ETH Zurich), Tino Rellstab (ETH Zurich), Laurent Vanbever (ETH Zurich)

    • Abstract: Each year at ETH Zurich, around 100 students collectively build and operate their very own Internet infrastructure composed of hundreds of routers and dozens of Autonomous Systems (ASes). Their goal? Enabling Internet-wide connectivity. AB@We find this class-wide project to be invaluable in teaching our students how the Internet infrastructure practically works. Among others, our students have a much deeper understanding of Internet operations alongside their pitfalls. Besides students tend to love the project: clearly the fact that all of them need to cooperate for the entire Internet to work is empowering. In this paper, we describe the overall design of our teaching platform, how we use it, and interesting lessons we have learnt over the years. We also make our platform openly available.

       

  • 4:00 - 4:15 pm EDT
               &
    3:00 - 3:15 am EDT

    Deprecating The TCP Macroscopic Model

    Matt Mathis (Google, Inc) and Jamshid Mahdavi (WhatsApp, Inc)

    • Abstract: The TCP Macroscopic Model will be completely obsolete soon. It was a closed form performance model for Van Jacobson's landmark congestion control algorithms presented at Sigcomm'88. Jacobson88 requires relatively large buffers to function as intended, while Moore's law is making them uneconomical.

      BBR-TCP is a break from the past, unconstrained by many of the assumptions and principles defined in Jacobson88. It already out performs Reno and CUBIC TCP over large portions of the Internet, generally without creating queues of the sort needed by earlier congestion control algorithms. It offers the potential to scale better while using less queue buffer space than existing algorithms.

      Because BBR-TCP is built on an entirely new set of principles, it has the potential to deprecate many things, including the Macroscopic Model. New research will be required to lay a solid foundation for an Internet built on BBR.

       

  • 4:15 - 4:30 pm EDT
               &
    3:15 - 3:30 am EDT

    Securing Linux with a Faster and Scalable Iptables

    Sebastiano Miano (Politecnico di Torino), Matteo Bertrone (Politecnico di Torino), Fulvio Risso (Politecnico di Torino), Mauricio Vásquez Bernal (Politecnico di Torino), Yunsong Lu (Futurewei Technologies, Inc.), Jianwen Pi (Futurewei Technologies, Inc.)

    • Abstract: The sheer increase in network speed and the massive deployment of containerized applications in a Linux server has led to the consciousness that iptables, the current de-facto firewall in Linux, may not be able to cope with the current requirements particularly in terms of scalability in the number of rules. This paper presents an eBPF-based firewall, bpf-iptables, which emulates the iptables filtering semantic while guaranteeing higher throughput. We compare our implementation against the current version of iptables and other Linux firewalls, showing how it achieves a notable boost in terms of performance particularly when a high number of rules is involved. This result is achieved without requiring custom kernels or additional software frameworks (e.g., DPDK) that could not be allowed in some scenarios such as public data-centers.

       

  • 4:30 - 5:30 pm EDT      Posters and Demos Session II

    Go to Slack channel
  • 4:30 - 5:30 pm EDT Posters and Demos

  • Thursday, August 13, 2020 EDT

  • 10:00 - 10:30 am EDT  &  9:00 - 9:30 pm EDT      Invited/Industry Talk #1

    Session chair(s): Jennifer Rexford and Nick McKeown
    Go to Slack channel
  • 10:00 - 10:30 am EDT
               &
    9:00 - 9:30 pm EDT

    What's Beyond 5G?

    Speakers: Andrea Goldsmith (Stanford University)

  • 10:30 - 11:00 am EDT  &  9:30 - 10:00 pm EDT      Invited/Industry Talk #2

    Session chair(s): Jennifer Rexford and Nick McKeown
    Go to Slack channel
  • 10:30 - 11:00 am EDT
               &
    9:30 - 10:00 pm EDT

    Zoom: A Conversation

    Speakers: Eric Yuan (CEO, Zoom)

  • 11:00 - 11:59 am EDT  &  10:00 - 11:00 pm EDT      Technical Session 11: NFV: Making Networks Function Virtually

    Session chairs: Aurojit Panda (western hemisphere) & Danyang Zhuo (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Network Function Virtualization     Programmable switches
  • 11:00 - 11:15 am EDT
               &
    10:00 - 10:15 pm EDT

    Fault Tolerant Service Function Chaining

    Milad Ghaznavi, Elaheh Jalalpour, Bernard Wong, Raouf Boutaba, Ali José Mashtizadeh (University of Waterloo)

    • Abstract: Network traffic typically traverses a sequence of middleboxes forming a service function chain, or simply a chain. Tolerating failures when they occur along chains is imperative to the availability and reliability of enterprise applications. Making a chain fault-tolerant is challenging since, in the event of failures, the state of faulty middleboxes must be correctly and quickly recovered while providing high throughput and low latency.

      In this paper, we introduce FTC, a system design and protocol for fault-tolerant service function chaining. FTC provides strong consistency with up to f middlebox failures for chains of length f + 1 or longer without requiring dedicated replica nodes. In FTC, state updates caused by packet processing at a middlebox are collected, piggybacked onto the packet, and sent along the chain to be replicated. Our evaluation shows that compared with the state of art [51], FTC improves throughput by 2-3.5X for a chain of two to five middleboxes.

       

  • 11:15 - 11:30 am EDT
               &
    10:15 - 10:30 pm EDT

    Gallium: Automated Software Middlebox Offloading to Programmable Switches

    Kaiyuan Zhang (University of Washington); Danyang Zhuo (Duke University); Arvind Krishnamurthy (University of Washington)

    • Abstract: Researchers have shown that offloading software middleboxes (e.g., NAT, firewall, load balancer) to programmable switches can yield orders-of-magnitude performance gains. However, it requires manually selecting the middle-box components to offload and rewriting the offloaded code in P4, a domain-specific language for programmable switches. We design and implement Gallium, a compiler that transforms an input software middlebox into two parts---a P4 program that runs on a programmable switch and an x86 non-offloaded program that runs on a regular middlebox server. Gallium ensures that (1) the combined effect of the P4 program and the non-offloaded program is functionally equivalent to the input middlebox program, (2) the P4 program respects the resource constraints in the programmable switch, and (3) the run-to-completion semantics are met under concurrent execution. Our evaluations show that Gallium saves 21-79% of processing cycles and reduces latency by about 31% across various software middleboxes.

       

  • 11:30 - 11:45 am EDT
               &
    10:30 - 10:45 pm EDT

    Contention-Aware Performance Prediction for Virtualized Network Functions

    Antonis Manousis, Rahul Anand Sharma, Vyas Sekar, Justine Sherry (Carnegie Mellon University)

    • Abstract: At the core of Network Functions Virtualization lie Network Functions (NFs) that run co-resident on the same server, contend over its hardware resources and, thus, might suffer from reduced performance relative to running alone on the same hardware. Therefore, to efficiently manage resources and meet performance SLAs, NFV orchestrators need mechanisms to predict contention-induced performance degradation. In this work, we find that prior performance prediction frameworks suffer from poor accuracy on modern architectures and NFs because they treat memory as a monolithic whole. In addition, we show that, in practice, there exist multiple components of the memory subsystem that can separately induce contention. By precisely characterizing (1) the pressure each NF applies on the server's shared hardware resources (contentiousness) and (2) how susceptible each NF is to performance drop due to competing contentiousness (sensitivity), we develop SLOMO, a multivariable performance prediction framework for Network Functions. We show that relative to prior work SLOMO reduces prediction error by 2-5x and enables 6-14% more efficient cluster utilization. SLOMO's codebase can be found at https://github.com/cmu-snap/SLOMO.

       

  • 11:45 - 11:59 am EDT
               &
    10:45 - 11:00 pm EDT

    Microscope: Queue-based Performance Diagnosis for Network Functions

    Junzhi Gong, Yuliang Li (Harvard University); Bilal Anwer (AT&T Labs Research); Aman Shaikh (AT&T Labs - Research); Minlan Yu (Harvard University)

    • Abstract: By moving monolithic network appliances to software running on commodity hardware, network function virtualization allows flexible resource sharing among network functions and achieves scalability with low cost. However, due to resource contention, network functions can suffer from performance problems that are hard to diagnose. In particular, when many flows traverse a complex topology of NF instances, it is hard to pinpoint root causes for a flow experiencing performance issues such as low throughput or high latency. Simply maintaining resource counters at individual NFs is not sufficient since the effect of resource contention can propagate across NFs and over time. In this paper, we introduce Microscope, a performance diagnosis tool, for network functions that leverages queuing information at NFs to identify the root causes (i.e., resources, NFs, traffic patterns of flows etc.). Our evaluation on realistic NF chains and traffic shows that we can correctly capture root causes behind 89.7% of performance impairments, up to 2.5 times more than the state-of-the-art tools with low overhead.

       

  • 12:00 - 1:00 pm EDT  &  11:00 - 11:59 pm EDT      Technical Session 12: Data Centers Need More New Gadgets

    Session chairs: Radhika Niranjan Mysore (western hemisphere) & Dongsu Han (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Data centers: Advanced networking
  • 12:00 - 12:15 pm EDT
               &
    11:00 - 11:15 pm EDT

    Sirius: A Flat Datacenter Network with Nanosecond Optical Switching

    Hitesh Ballani, Paolo Costa, Raphael Behrendt, Daniel Cletheroe, Istvan Haller, Krzysztof Jozwik, Fotini Karinou, Sophie Lange, Kai Shi, Benn Thomsen, Hugh Williams (Microsoft Research)

    • Abstract: The increasing gap between the growth of datacenter traffic and electrical switch capacity is expected to worsen due to the slowdown of Moore's law, motivating the need for a new switching technology for the post-Moore's law era that can meet the increasingly stringent requirements of hardware-driven cloud workloads. We propose Sirius, an optically-switched network for datacenters providing the abstraction of a single, high-radix switch that can connect thousands of nodes---racks or servers---in a datacenter while achieving nanosecond-granularity reconfiguration. At its core, Sirius uses a combination of tunable lasers and simple, passive gratings that route light based on its wavelength. Sirius' switching technology and topology is tightly codesigned with its routing and scheduling and with novel congestion-control and time-synchronization mechanisms to achieve a scalable yet flat network that can offer high bandwidth and very low end-to-end latency. Through a small-scale prototype using a custom tunable laser chip that can tune in less than 912 ps, we demonstrate 3.84 ns end-to-end reconfiguration atop 50 Gbps channels. Through large-scale simulations, we show that Sirius can approximate the performance of an ideal, electrically-switched non-blocking network with up to 74-77% lower power.

       

  • 12:15 - 12:30 pm EDT
               &
    11:15 - 11:30 pm EDT

    1RMA: Re-envisioning Remote Memory Access for Multi-tenant Datacenters

    Arjun Singhvi (University of Wisconsin - Madison); Aditya Akella (University of Wisconsin - Madison and Google, Inc); Dan Gibson, Thomas F. Wenisch, Monica Wong-Chan, Sean Clark, Milo M. K. Martin, Moray McLaren, Prashant Chandra, Rob Cauble, Hassan M. G. Wassel, Behnam Montazeri (Google, Inc.); Simon L. Sabato (Lilac Cloud); Joel Scherpelz (unaffiliated); Amin Vahdat (Google, Inc.)

    • Abstract: Remote Direct Memory Access (RDMA) plays a key role in supporting performance-hungry datacenter applications. However, existing RDMA technologies are ill-suited to multi-tenant datacenters, where applications run at massive scales, tenants require isolation and security, and the workload mix changes over time. Our experiences seeking to operationalize RDMA at scale indicate that these ills are rooted in standard RDMA's basic design attributes: connectionorientedness and complex policies baked into hardware.

      We describe a new approach to remote memory access -- One-Shot RMA (1RMA) -- suited to the constraints imposed by our multi-tenant datacenter settings. The 1RMA NIC is connection-free and fixed-function; it treats each RMA operation independently, assisting software by offering fine-grained delay measurements and fast failure notifications. 1RMA software provides operation pacing, congestion control, failure recovery, and inter-operation ordering, when needed. The NIC, deployed in our production datacenters, supports encryption at line rate (100Gbps and 100M ops/sec) with minimal performance/availability disruption for encryption key rotation.

       

  • 12:30 - 12:45 pm EDT
               &
    11:30 - 11:45 pm EDT

    SmartNIC Performance Isolation with FairNIC: Programmable Networking for the Cloud

    Stewart Grant, Anil Yelam (UC San Diego); Maxwell Bland (University of Illinois at Urbana-Champaign); Alex C. Snoeren (UC San Diego)

    • Abstract: Multiple vendors have recently released SmartNICs that provide both special-purpose accelerators and programmable processing cores that allow increasingly sophisticated packet processing tasks to be offloaded from general-purpose CPUs. Indeed, leading data-center operators have designed and deployed SmartNICs at scale to support both network virtualization and application-specific tasks. Unfortunately, cloud providers have not yet opened up the full power of these devices to tenants, as current runtimes do not provide adequate isolation between individual applications running on the SmartNICs themselves.

      We introduce FairNIC, a system to provide performance isolation between tenants utilizing the full capabilities of a commodity SoC SmartNIC. We implement FairNIC on Cavium LiquidIO 2360s and show that we are able to isolate not only typical packet processing, but also prevent MIPS-core cache pollution and fairly share access to fixed-function hardware accelerators. We use FairNIC to implement NIC-accelerated OVS and key/value store applications and show that they both can cohabitate on a single NIC using the same port, where the performance of each is unimpacted by other tenants. We argue that our results demonstrate the feasibility of sharing SmartNICs among virtual tenants, and motivate the development of appropriate security isolation mechanisms.

       

  • 12:45 - 1:00 pm EDT
               &
    11:45 - 11:59 pm EDT

    Beyond the mega-data center: networking multi-data center regions

    Vojislav Dukic (ETH Zurich); Ginni Khanna, Christos Gkantsidis, Thomas Karagiannis, Francesca Parmigiani (Microsoft); Ankit Singla (ETH Zurich); Mark Filer, Jeffrey L. Cox, Anna Ptasznik, Nick Harland, Winston Saunders, Christian Belady (Microsoft)

    • Abstract: The difficulty of building large data centers in dense metro areas is pushing big cloud providers towards a different approach to scaling: multiple smaller data centers within tens of kilometers of each other, comprising a "region". We show that networking this small number of nearby sites with each other is a surprisingly challenging and multi-faceted problem. We draw out the operational goals and constraints of such networks, and highlight the design trade-offs involved using data from Microsoft Azure's regions.

      Our analysis of the design space shows that network topologies that achieve lower latency and allow greater flexibility in data center placement are, unfortunately, encumbered by their much greater cost and complexity. We thus present and demonstrate a novel optical-circuit-switched architecture, Iris, that lowers these cost and complexity barriers, making a richer topology design space more accessible to operators of regional networks. With Iris, topologies which, in comparison to a simple hub-and-spoke topology can increase the area in which a new DC can be placed by 2-5x, can be implemented at a cost within 1.1x of the simple hub-and-spoke topology, and 7x cheaper than a natural packet-switched network.

       

  • 1:05 - 1:40 pm EDT  &  12:05 - 12:40 am EDT      Panel

    Session chair(s): Shyam Gollakota     (happening in parallel with the Speed Networking 1:1 Sessions, see below)
    Go to Slack channel
  • 1:05 - 1:40 pm EDT
               &
    12:05 - 12:40 am EDT

    A Conversation on Future Embedded Systems: Living IoT, Nano Satellites and Mobile health

    Speakers: Tanzeem Choudhury (Cornell Tech), Shyam Gollakota (University of Washington), Luca Mottola (Politecnico di Milano)

  • 1:05 - 1:40 pm EDT   &   12:05 - 12:40 am EDT Speed Networking 1:1 Sessions (Go to Slack channel)

  • 1:45 - 3:00 pm EDT  &  12:45 - 2:00 am EDT      Technical Session 13: Wireless: Break Free of Wires of All Lengths

    Session chairs: Aaron Schulman (western hemisphere) & Kun Tan (eastern hemisphere)
    Go to Slack channel
  • 1:45 - 2:00 pm EDT
               &
    12:45 - 1:00 am EDT

    NFC+: Breaking NFC Networking Limits through Resonance Engineering

    Renjie Zhao (Alibaba Group & University of California San Diego); Purui Wang (Alibaba Group & Peking University); Yunfei Ma, Pengyu Zhang, Hongqiang Harry Liu, Xianshang Lin (Alibaba Group); Xinyu Zhang (University of California San Diego); Chenren Xu (Peking University); Ming Zhang (Alibaba Group)

    • Abstract: Current UHF RFID systems suffer from two long-standing problems: 1) miss-reading non-line-of-sight or misoriented tags and 2) cross-reading undesired, distant tags due to multi-path reflections. This paper proposes a novel system, NFC+, to overcome the fundamental challenges. NFC+ is a magnetic field reader, which can inventory standard NFC tagged objects with a reasonably long range and arbitrary orientation. NFC+ achieves this by leveraging physical and algorithmic techniques based on magnetic resonance engineering. We build a prototype of NFC+ and conduct extensive evaluations in a logistic network. Comparing to UHF RFID, we find that NFC+ can reduce the miss-reading rate from 23% to 0.03%, and cross-reading rate from 42% to 0, for randomly oriented objects. NFC+ demonstrates high robustness for RFID unfriendly media (e.g., water bottles and metal cans). It can reliably read commercial NFC tags at a distance of up to 3 meters which, for the first time, enables NFC to be directly applied to practical logistics network applications.

       

  • 2:00 - 2:15 pm EDT
               &
    1:00 - 1:15 am EDT

    TACK: Improving Wireless Transport Performance by Taming Acknowledgments

    Tong Li (Huawei Technologies Co., Ltd.); Kai Zheng (Huawei Technologies Co. Ltd.); Ke Xu (Tsinghua University & BNRist & PCL); Rahul Arvind Jadhav, Tao Xiong (Huawei Technologies Co. Ltd.); Keith Winstein (Stanford University); Kun Tan (Huawei Technologies Co. Ltd.)

    • Abstract: The shared nature of the wireless medium induces contention between data transport and backward signaling, such as acknowledgement. The current way of TCP acknowledgment induces control overhead which is counter-productive for TCP performance especially in wireless local area network (WLAN) scenarios.

      In this paper, we present a new acknowledgement called TACK ("Tame ACK"), as well as its TCP implementation TCP-TACK. TCP-TACK works on top of commodity WLAN, delivering high wireless transport goodput with minimal control overhead in the form of ACKs, without any hardware modification. To minimize ACK frequency, TACK abandons the legacy received-packet-driven ACK. Instead, it balances byte-counting ACK and periodic ACK so as to achieve a controlled ACK frequency. Evaluation results show that TCP-TACK achieves significant advantages over legacy TCP in WLAN scenarios due to less contention between data packets and ACKs. Specifically, TCP-TACK reduces over 90% of ACKs and also obtains an improvement of ~ 28% on good-put. We further find it performs equally well as high-speed TCP variants in wide area network (WAN) scenarios, this is attributed to the advancements of the TACK-based protocol design in loss recovery, round-trip timing, and send rate control.

       

  • 2:15 - 2:30 pm EDT
               &
    1:15 - 1:30 am EDT

    Beyond-5G Reliable Extreme Mobility Management

    Yuanjie Li (Hewlett Packard Labs); Qianru Li, Zhehui Zhang (University of California, Los Angeles); Ghufran Baig, Lili Qiu (University of Texas at Austin); Songwu Lu (University of California, Los Angeles)

    • Abstract: Extreme mobility has become a norm rather than an exception. However, 4G/5G mobility management is not always reliable in extreme mobility, with non-negligible failures and policy conflicts. The root cause is that, existing mobility management is primarily based on wireless signal strength. While reasonable in static and low mobility, it is vulnerable to dramatic wireless dynamics from extreme mobility in triggering, decision, and execution. We devise REM, Reliable Extreme Mobility management for 4G, 5G, and beyond. REM shifts to movement-based mobility management in the delay-Doppler domain. Its signaling overlay relaxes feedback via cross-band estimation, simplifies policies with provable conflict freedom, and stabilizes signaling via scheduling-based OTFS modulation. Our evaluation with operational high-speed rail datasets shows that, REM reduces failures comparable to static and low mobility, with low signaling and latency cost.

       

  • 2:30 - 2:45 pm EDT
               &
    1:30 - 1:45 am EDT

    Understanding Operational 5G: A First Measurement Study on Its Coverage, Performance and Energy Consumption

    Dongzhu Xu, Anfu Zhou (Beijing University of Posts and Telecommunications); Xinyu Zhang (University of California San Diego); Guixian Wang, Xi Liu, Congkai An, Yiming Shi, Liang Liu, Huadong Ma (Beijing University of Posts and Telecommunications)

    • Abstract: 5G, as a monumental shift in cellular communication technology, holds tremendous potential for spurring innovations across many vertical industries, with its promised multi-Gbps speed, sub-10 ms low latency, and massive connectivity. On the other hand, as 5G has been deployed for only a few months, it is unclear how well and whether 5G can eventually meet its prospects. In this paper, we demystify operational 5G networks through a first-of-its-kind cross-layer measurement study. Our measurement focuses on four major perspectives: (i) Physical layer signal quality, coverage and hand-off performance; (ii) End-to-end throughput and latency; (iii) Quality of experience of 5G's niche applications (e.g., 4K/5.7K panoramic video telephony); (iv) Energy consumption on smartphones. The results reveal that the 5G link itself can approach Gbps throughput, but legacy TCP leads to surprisingly low capacity utilization (< 32%), latency remains too high to support tactile applications and power consumption escalates to 2 - 3x over 4G. Our analysis suggests that the wireline paths, upper-layer protocols, computing and radio hardware architecture need to co-evolve with 5G to form an ecosystem, in order to fully unleash its potential.

       

  • 2:45 - 3:00 pm EDT
               &
    1:45 - 2:00 am EDT

    A Low Latency and Consistent Cellular Control Plane

    Mukhtiar Ahmad, Syed Usman Jafri, Azam Ikram, Wasiq Noor Ahmad Qasmi, Muhammad Ali Nawazish, Zartash Afzal Uzmi, Zafar Ayyub Qazi (LUMS)

    • Abstract: 5G networks aim to provide ultra-low latency and higher reliability to support emerging and near real-time applications such as augmented and virtual reality, remote surgery, self-driving cars, and multi-player online gaming. This imposes new requirements on the design of cellular core networks. A key component of the cellular core is the control plane. Time to complete control plane operations (e.g. mobility handoff, service establishment) directly impacts the delay experienced by end-user applications. In this paper, we design Neutrino, a cellular control plane that provides users an abstraction of reliable access to cellular services while ensuring lower latency. Our testbed evaluations based on real cellular control traffic traces show that Neutrino provides an improvement in control procedure completion times by up to 3.1x without failures, and up to 5.6x under control plane failures, over existing cellular core proposals. We also show how these improvements translate into improving end-user application performance: for AR/VR applications and self-driving cars, Neutrino performs up to 2.5x and up to 2.8x better, respectively, as compared to existing EPC.

       

  • 3:00 - 4:15 pm EDT  &  2:00 - 3:15 am EDT      Technical Session 14: Serving All The People

    Session chairs: Sanjay Rao (western hemisphere) & Sangeetha Abdu Jyothi (eastern hemisphere)
    Go to Slack channel
    Related Topic Preview(s):     Video + ML
  • 3:00 - 3:15 pm EDT
               &
    2:00 - 2:15 am EDT

    Akamai DNS: Providing Authoritative Answers to the World’s Queries

    Kyle Schomp, Onkar Bhardwaj, Eymen Kurdoglu, Mashooq Muhaimen (Akamai Technologies); Ramesh K. Sitaraman (University of Massachusetts at Amherst/Akamai Technologies)

    • Abstract: We present Akamai DNS, one of the largest authoritative DNS infrastructures in the world, that supports the Akamai content delivery network (CDN) as well as authoritative DNS hosting and DNS-based load balancing services for many enterprises. As the starting point for a significant fraction of the world's Internet interactions, Akamai DNS serves millions of queries each second and must be resilient to avoid disrupting myriad online services, scalable to meet the ever increasing volume of DNS queries, performant to prevent user-perceivable performance degradation, and reconfigurable to react quickly to shifts in network conditions and attacks. We outline the design principles and architecture used to achieve Akamai DNS's goals, relating the design choices to the system workload and quantifying the effectiveness of those designs. Further, we convey insights from operating the production system that are of value to the broader research community.

       

  • 3:15 - 3:30 pm EDT
               &
    2:15 - 2:30 am EDT

    Zero Downtime Release: Disruption-free Load Balancing of a Multi-Billion User Website

    Usama Naseer (Brown University); Luca Niccolini, Udip Pant, Alan Frindell, Ranjeeth Dasineni (Facebook); Theophilus A. Benson (Brown University)

    • Abstract: Modern network infrastructure has evolved into a complex organism to satisfy the performance and availability requirements for the billions of users. Frequent releases such as code upgrades, bug fixes and security updates have become a norm. Millions of globally distributed infrastructure components including servers and load-balancers are restarted frequently from multiple times per-day to per-week. However, every release brings possibilities of disruptions as it can result in reduced cluster capacity, disturb intricate interaction of the components operating at large scales and disrupt the end-users by terminating their connections. The challenge is further complicated by the scale and heterogeneity of supported services and protocols.

      In this paper, we leverage different components of the end-to-end networking infrastructure to prevent or mask any disruptions in face of releases. Zero Downtime Release is a collection of mechanisms used at Facebook to shield the end-users from any disruptions, preserve the cluster capacity and robustness of the infrastructure when updates are released globally. Our evaluation shows that these mechanisms prevent any significant cluster capacity degradation when a considerable number of productions servers and proxies are restarted and minimizes the disruption for different services (notably TCP, HTTP and publish/subscribe).

       

  • 3:30 - 3:45 pm EDT
               &
    2:30 - 2:45 am EDT

    Come as You Are: Helping Unmodified Clients Bypass Censorship with Server-side Evasion

    Kevin Bock, George Hughey, Louis-Henri Merino, Tania Arya, Daniel Liscinsky, Regina Pogosian, Dave Levin (University of Maryland)

    • Abstract: Decades of work on censorship evasion have resulted in myriad ways to empower clients with the ability to access censored content, but to our knowledge all of them have required some degree of client-side participation. Having to download and run anti-censorship software can put users at risk, and does not help the many users who do not even realize they are being censored in the first place.

      In this paper, we present the first purely server-side censorship evasion strategies---11 in total. We extend a recent tool, Geneva, to automate the discovery and implementation of server-side strategies, and we apply it to four countries (China, India, Iran, and Kazakhstan) and five protocols (DNS-over-TCP, FTP, HTTP, HTTPS, and SMTP). We also perform follow-on experiments to understand why the strategies Geneva finds work, and to glean new insights into how censors operate. Among these, we find that China runs a completely separate network stack (each with its own unique bugs) for each application-layer protocol that it censors.

      The server-side techniques we find are easier and safer to deploy than client-side strategies. Our code and data are publicly available.

       

  • 3:45 - 4:00 pm EDT
               &
    2:45 - 3:00 am EDT

    Caching with Delayed Hits

    Nirav Atre, Justine Sherry, Weina Wang (Carnegie Mellon University); Daniel Berger (Microsoft Research)

    • Abstract: Caches are at the heart of latency-sensitive systems. In this paper, we identify a growing challenge for the design of latency-minimizing caches called delayed hits. Delayed hits occur at high throughput, when multiple requests to the same object queue up before an outstanding cache miss is resolved. This effect increases latencies beyond the predictions of traditional caching models and simulations; in fact, caching algorithms are designed as if delayed hits simply didn't exist. We show that traditional caching strategies -- even so called 'optimal' algorithms -- can fail to minimize latency in the presence of delayed hits. We design a new, latency-optimal offline caching algorithm called belatedly which reduces average latencies by up to 45% compared to the traditional, hit-rate optimal Belady's algorithm. Using belatedly as our guide, we show that incorporating an object's 'aggregate delay' into online caching heuristics can improve latencies for practical caching systems by up to 40%. We implement a prototype, Minimum-AggregateDelay (mad), within a CDN caching node. Using a CDN production trace and backends deployed in different geographic locations, we show that mad can reduce latencies by 12-18% depending on the backend RTTs.

       

  • 4:00 - 4:15 pm EDT
               &
    3:00 - 3:15 am EDT

    Interpreting Deep Learning-Based Networking Systems

    Zili Meng, Minhu Wang, Jiasong Bai, Mingwei Xu (Tsinghua University); Hongzi Mao (Massachusetts Institute of Technology); Hongxin Hu (Clemson University)

    • Abstract: While many deep learning (DL)-based networking systems have demonstrated superior performance, the underlying Deep Neural Networks (DNNs) remain blackboxes and stay uninterpretable for network operators. The lack of interpretability makes DL-based networking systems prohibitive to deploy in practice. In this paper, we propose Metis, a framework that provides interpretability for two general categories of networking problems spanning local and global control. Accordingly, Metis introduces two different interpretation methods based on decision tree and hypergraph, where it converts DNN policies to interpretable rule-based controllers and highlight critical components based on analysis over hypergraph. We evaluate Metis over two categories of state-of-the-art DL-based networking systems and show that Metis provides human-readable interpretations while preserving nearly no degradation in performance. We further present four concrete use cases of Metis, showcasing how Metis helps network operators to design, debug, deploy, and ad-hoc adjust DL-based networking systems.

       

  • 4:30 - 5:00 pm EDT      Invited/Industry Talk #3

    Session chair(s): Ratul Mahajan
    Go to Slack channel
  • 4:30 - 5:00 pm EDT
               &
    3:30 - 4:00 am EDT

    The network as a programmable platform: fertile new ground for networking research

    Speakers: Nick McKeown (Stanford University)

  • 5:00 - 5:15 pm EDT
               &
    4:00 - 4:15 am EDT

    Closing

    Speakers: Vishal Misra (Columbia University, USA), Henning Schulzrinne (Columbia University, USA), Sujata Banerjee (VMware Research), Ratul Mahajan (University of Washington, Intentionet)

  • 5:15- 6:15 pm EDT   &   4:15 - 5:15 am EDT Virtual Tours: Minecraft + Videos (Go to Slack channel)