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Steve Padgett

Steve Padgett

Authored Publications
Google Publications
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    B4 and After: Managing Hierarchy, Partitioning, and Asymmetry for Availability and Scale in Google's Software-Defined WAN
    Min Zhu
    Rich Alimi
    Kondapa Naidu Bollineni
    Chandan Bhagat
    Sourabh Jain
    Jay Kaimal
    Jeffrey Liang
    Kirill Mendelev
    Faro Thomas Rabe
    Saikat Ray
    Malveeka Tewari
    Monika Zahn
    Joon Ong
    SIGCOMM'18 (2018)
    Preview abstract Private WANs are increasingly important to the operation of enterprises, telecoms, and cloud providers. For example, B4, Google’s private software-defined WAN, is larger and growing faster than our connectivity to the public Internet. In this paper, we present the five-year evolution of B4. We describe the techniques we employed to incrementally move from offering best-effort content-copy services to carrier-grade availability, while concurrently scaling B4 to accommodate 100x more traffic. Our key challenge is balancing the tension introduced by hierarchy required for scalability, the partitioning required for availability, and the capacity asymmetry inherent to the construction and operation of any large-scale network. We discuss our approach to managing this tension: i) we design a custom hierarchical network topology for both horizontal and vertical software scaling, ii) we manage inherent capacity asymmetry in hierarchical topologies using a novel traffic engineering algorithm without packet encapsulation, and iii) we re-architect switch forwarding rules via two-stage matching/hashing to deal with asymmetric network failures at scale. View details
    Taking the Edge off with Espresso: Scale, Reliability and Programmability for Global Internet Peering
    Matthew Holliman
    Gary Baldus
    Marcus Hines
    TaeEun Kim
    Ashok Narayanan
    Victor Lin
    Colin Rice
    Brian Rogan
    Bert Tanaka
    Manish Verma
    Puneet Sood
    Mukarram Tariq
    Dzevad Trumic
    Vytautas Valancius
    Calvin Ying
    Mahesh Kallahalla
    Sigcomm (2017)
    Preview abstract We present the design of Espresso, Google’s SDN-based Internet peering edge routing infrastructure. This architecture grew out of a need to exponentially scale the Internet edge cost-effectively and to enable application-aware routing at Internet-peering scale. Espresso utilizes commodity switches and host-based routing/packet processing to implement a novel fine-grained traffic engineering capability. Overall, Espresso provides Google a scalable peering edge that is programmable, reliable, and integrated with global traffic systems. Espresso also greatly accelerated deployment of new networking features at our peering edge. Espresso has been in production for two years and serves over 22% of Google’s total traffic to the Internet. View details
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