CCR Papers from April 2014

  • Dina Papagiannaki

    Welcome to the April 2014 issue for Computer Communications Review. I am really happy to see CCR increasing its presence in our community and serving as a venue where we express our opinions on the way our community is evolving, discussing its future, and publish papers that advance the state of the art in data communications. In the past 3 months, I have received a number of comments from members in the community, on previous published articles and expressing their willingness to contribute to its continued success. Thank you very much!

    This issue of CCR features 13 papers, out of which 6 are editorial notes. The technical papers cover wireless and wired networking solutions, as well as SDN. Our editorials cover workshop reports, but also opinion papers. Lastly, I am very happy to also include an editorial on MCKit, the smartphone app that was launched for SIGCOMM 2013, and the organizers’ thoughts on how well it worked, how it was built, and results on how it was used. I hope it proves to be useful as we are getting close to this year’s SIGCOMM in Chicago.

    One of the discussions we have started in the community has to do with our actual impact on commercial products. March was the month of the Mobile World Congress (MWC), in Barcelona, the premier industry venue in mobile communications and products. It was really exciting to see one of our community’s outcomes presented during the venue and receiving tremendous coverage by the media. I am referring to Kumu Networks, a startup company founded by Sachin Katti, Steven Hong, Jeffrey Mehlman, and Mayank Jain, whose seeds were sown in Stanford University, and that aims to commercialize full duplex radio technology. The technology behind Kumu Network was published in SIGCOMM 2012, SIGCOMM 2013, as well as NSDI, Mobicom and Hotnets in the past 4 years. Kumu Networks is a clear testament to the quality of work done in our community, and its relevance in the market. A tremendous achievement by all standards.

    This issue also marks the end of term for Sharad Agarwal, from Microsoft Research in Redmond. I really wanted to thank Sharad for his contributions throughout his tenure at CCR. We will miss your perspective, as well as some of the greatest public reviews CCR has even seen!

    We also say goodbye to Matteo Varvello, from Bell Labs. Matteo has been the heart behind the online version of CCR. I would really like to thank him for all his help throughout the past year, and welcome Prof. Mike Wittie, from Montana State University, who joins full of energy as the new CCR publications chair.

    With all that, I hope you enjoy this issue and I am always at your disposal in case of questions or comments.

  • X. Yao, W. Wang, S. Yang, Y. Cen, X. Yao, T. Pan

    This paper proposed an IPB-frame Adaptive Mapping Mechanism (AMM) to improve the video transmission quality over IEEE 802.11e Wireless Local Area Networks (WLANs). Based on the frame structure of hierarchical coding technology, the probability of each frame allocated to the most appropriate Access Category (AC) was dynamically updated according to its importance and traffic load of each AC. Simulation results showed the superior performance of the proposed AMM by comparing with three other existing mechanisms in terms of three objective metrics.

    Joseph Camp
  • F. Ge, L. Tan

    A communication network usually has data packets and acknowledge (ACK) packets being transmitted in opposite directions. ACK packet flows may affect the performance of data packet flows, which is unfortunately not considered in the usual network utility maximization (NUM) model. This paper presents a NUM model in networks with two-way flows (NUMtw) by adding a routing matrix to cover ACK packet flows. The source rates are obtained by solving the dual model and the relation to the routing matrix of ACK packet flows is disclosed. Furthermore, the source rates in networks with one-way flows by the usual NUM model are compared to those in networks with two-way flows by the NUMtw model.

    Nikolaos Laoutaris
  • A. Lodhi, N. Larson, A. Dhamdhere, C. Dovrolis, K. Claffy

    In this study we mine one of the few sources of public data available about the interdomain peering ecosytem: PeeringDB [1], an online database where participating networks contribute information about their peering policies, traffic volumes and presence at various geographic locations. Although established to support the practical needs of operators, this data also provides a valuable source of information to researchers. Using BGP data to cross-validate three years of PeeringDB snapshots, we find that PeeringDB membership is reasonably representative of the Internet’s transit, content, and access providers in terms of business types and geography of participants, and PeeringDB data is generally up-to-date. We find strong correlations among different measures of network size - BGP-advertised address space, PeeringDB-reported traffic volume and presence at peering facilities, and between these size measures and advertised peering policies.

    Renata Teixeira
  • M. Raju, A. Wundsam, M. Yu

    In spite of the standardization of the OpenFlow API, it is very difficult to write an SDN controller application that is portable (i.e., guarantees correct packet processing over a wide range of switches) and achieves good performance (i.e., fully leverages switch capabilities). This is because the switch landscape is fundamentally diverse in performance, feature set and supported APIs. We propose to address this challenge via a lightweight portability layer that acts as a rendezvous point between the requirements of controller application and the vendor knowledge of switch implementations. Above, applications specify rules in virtual flow tables annotated with semantic intents and expectations. Below, vendor specific drivers map them to optimized switch-specific rule sets. NOSIX represents a first step towards achieving both portability and good performance across a diverse set of switches.

    Hitesh Ballani
  • R. Singh, T. Brecht, S. Keshav

    The number of publicly accessible virtual execution environments (VEEs) has been growing steadily in the past few years. To be accessible by clients, such VEEs need either a public IPv4 or a public IPv6 address. However, the pool of available public IPv4 addresses is nearly depleted and the low rate of adoption of IPv6 precludes its use. Therefore, what is needed is a way to share precious IPv4 public addresses among a large pool of VEEs. Our insight is that if an IP address is assigned at the time of a client DNS request for the VEE’s name, it is possible to share a single public IP address amongst a set of VEEs whose workloads are not network intensive, such as those hosting personal servers or performing data analytics. We investigate several approaches to multiplexing a pool of global IP addresses among a large number of VEEs, and design a system that overcomes the limitations of current approaches. We perform a qualitative and quantitative comparison of these solutions. We find that upon receiving a DNS request from a client, our solution has a latency as low as 1 ms to allocate a public IP address to a VEE, while keeping the size of the required IP address pool close to the minimum possible.

    Phillipa Gill
  • G. Bianchi, M. Bonola, A. Capone, C. Cascone

    Software Defined Networking envisions smart centralized controllers governing the forwarding behavior of dumb low-cost switches. But are “dumb” switches an actual strategic choice, or (at least to some extent) are they a consequence of the lack of viable alternatives to OpenFlow as programmatic data plane forwarding interface? Indeed, some level of (programmable) control logic in the switches might be beneficial to offload logically centralized controllers (de facto complex distributed systems) from decisions just based on local states (versus network-wide knowledge), which could be handled at wire speed inside the device itself. Also, it would reduce the amount of flow processing tasks currently delegated to specialized middleboxes. The underlying challenge is: can we devise a stateful data plane programming abstraction (versus the stateless OpenFlow match/action table) which still entails high performance and remains consistent with the vendors’ preference for closed platforms? We posit that a promising answer revolves around the usage of extended finite state machines, as an extension (super-set) of the OpenFlow match/action abstraction. We concretely turn our proposed abstraction into an actual table-based API, and, perhaps surprisingly, we show how it can be supported by (mostly) reusing core primitives already implemented in OpenFlow devices.

    Hitesh Ballani
  • M. Honda, F. Huici, C. Raiciu, J. Araujo, L. Rizzo

    Recent studies show that more than 86% of Internet paths allow well-designed TCP extensions, meaning that it is still possible to deploy transport layer improvements despite the existence of middleboxes in the network. Hence, the blame for the slow evolution of protocols (with extensions taking many years to become widely used) should be placed on end systems. In this paper, we revisit the case for moving protocols stacks up into user space in order to ease the deployment of new protocols, extensions, or performance optimizations. We present MultiStack, operating system support for user- level protocol stacks. MultiStack runs within commodity operating systems, can concurrently host a large number of isolated stacks, has a fall-back path to the legacy host stack, and is able to process packets at rates of 10Gb/s. We validate our design by showing that our mux/demux layer can validate and switch packets at line rate (up to 14.88 Mpps) on a 10 Gbit port using 1-2 cores, and that a proof-of-concept HTTP server running over a basic userspace TCP outperforms by 18–90% both the same server and nginx running over the kernel’s stack.

    Sharad Agarwal
  • L. Zhan, D. Chiu

    Smart phones have become very popular. Most people attending a conference have a smartphone with them; so it is natural to think about how to build a mobile application to support a conference. In the process of organizing ACM Sigcomm 2013, we initiated a student project to build such a conference app. As a conference organizator, we had good motivation and inspiration to design functions we would like to support. In this paper, we share our experiences, in both functional design and implementation, as well as our experience in trying it out during Sigcomm 2013.

  • B. Carpenter

    This note describes how the Internet has got itself into deep trouble by over-reliance on IP addresses and discusses some possible ways forward.

  • S. Vissicchio, L. Vanbever, O. Bonaventure

    Software Defined Networking (SDN) promises to ease design, operation and management of communication networks. However, SDN comes with its own set of challenges, including incremental deployability, robustness, and scalability. Those challenges make a full SDN deployment difficult in the short-term and possibly inconvenient in the longer-term. In this paper, we explore hybrid SDN models that combine SDN with a more traditional networking approach based on distributed protocols. We show a number of use cases in which hybrid models can mitigate the respective limitations of traditional and SDN approaches, providing incentives to (partially) transition to SDN. Further, we expose the qualitatively diverse tradeoffs that are naturally achieved in hybrid models, making them convenient for different transition strategies and long-term network designs. For those reasons, we argue that hybrid SDN architectures deserve more attention from the scientific community.

  • E. Kenneally, M. Bailey

    The inaugural Cyber-security Research Ethics Dialogue & Strategy Workshop was held on May 23, 2013, in conjunction with the IEEE Security Privacy Symposium in San Francisco, California. CREDS embraced the theme of ethics-by-design in the context of cyber security research, and aimed to: - Educate participants about underlying ethics principles and applications; - Discuss ethical frameworks and how they are applied across the various stakeholders and respective communities who are involved; - Impart recommendations about how ethical frameworks can be used to inform policymakers in evaluating the ethical underpinning of critical policy decisions; - Explore cyber security research ethics techniques, tools, standards and practices so researchers can apply ethical principles within their research methodologies; and - Discuss specific case vignettes and explore the ethical impli- cations of common research acts and omissions.

  • Mat Ford

    This paper reports on a workshop convened to develop an action plan to reduce Internet latency. Internet latency has become a focus of attention at the leading edge of the industry as the desire to make Internet applications more responsive outgrows the ability of increased bandwidth to address this problem. There are fundamental limits to the extent to which latency can be reduced, but there is considerable capacity for improvement throughout the system, making Internet latency a multifaceted challenge. Perhaps the greatest challenge of all is to re-educate the mainstream of the industry to understand that bandwidth is not the panacea, and other optimizations, such as reducing packet loss, are at odds with latency reduction. For Internet applications, reducing the latency impact of sharing the communications medium with other users and applications is key. Current Internet network devices were often designed with a belief that additional buffering would reduce packet loss. In practice, this additional buffering leads to intermittently excessive latency and even greater packet loss under saturating load. For this reason, getting smarter queue management techniques more widely deployed is a high priority. We can reduce these intermittent increases in delay, sometimes by up to two orders of magnitude, by shifting the focus from packet loss avoidance to delay avoidance using technology that we already have developed, tested, implemented and deployed today. There is also plenty of scope for removing other major sources of delay. For instance, connecting to a website could be completed in one roundtrip (the time it takes for packets to travel from source to destination and back again) rather than three or four, by folding two or three rounds of flow and security set-up into the first data exchange, without compromising security or efficiency. Motivating the industry to deploy these advances needs to be aided by the availability of mass-market latency testing tools that could give consumers the information they need to gravitate towards low latency services, providers and products. There is no single network latency metric but several alternatives have been identified that compactly express aggregate delay (e.g. as relationships or a constellation), and tools that make use of these will give greater insight into the impact of changes and the diversity of Internet connections around the world. In many developing countries (and in rural regions of developed countries), aside from Internet access itself, there are significant structural issues, such as trombone routes through the developed world and a lack of content distribution networks (CDNs), that need to be addressed with more urgency than Active Queue Management (AQM) deployment, but the 'blank slate' of new deployments provides an opportunity to consider latency now. More widespread use of Internet exchange points for hosting local content and fostering local interconnections is key to addressing some of these structural challenges.

  • N. Feamster, J. Rexford, E. Zegura

    Software Defined Networking (SDN) is an exciting technology that enables innovation in how we design and manage networks. Although this technology seems to have appeared suddenly, SDN is part of a long history of efforts to make computer networks more programmable. In this paper, we trace the intellectual history of programmable networks, including active networks, early efforts to separate the control and data plane, and more recent work on OpenFlow and network operating systems. We highlight key concepts, as well as the technology pushes and application pulls that spurred each innovation. Along the way, we debunk common myths and misconceptions about the technologies and clarify the relationship between SDN and related technologies such as network virtualization.

  • A. Dainotti, K. Benson, A. King, kc claffy, M. Kallitsis, E. Glatz, X. Dimitropoulos

    This errata is to help viewers/readers identify/properly understand our contribution to the SIGCOMM CCR Newsletter. Volume 44 Issue 1, (January 2014) on pages 42-49.

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