SIGCOMM Networking Systems Award

The SIGCOMM Networking Systems Award is awarded to an institution or individual(s) to recognize the development of a networking system that has had a significant impact on the world of computer networking.
2021: B4: a globally-deployed software defined WAN
B4 is a private WAN connecting Google's data centers across the planet. At a time when there was significant debate in the community whether software defined networking could compete with high-end routers with on-box software running fully decentralized protocols, B4 established the practical viability of SDN at WAN scale. It supports massive bandwidth among a modest number of data-center sites. B4 supports shortest-path, low-loss connectivity for traditional applications, while also efficiently supporting specialized, high-traffic applications that can tolerate highly-utilized links and tunnels that exploit spare bandwidth on non-shortest-path routes. B4's global traffic engineering service drives links to near 100% utilization, while splitting application flows among multiple paths to balance capacity against application priority/demands, using edge-based rate-limiting and demand measurements. Experience with OpenFlow in B4 also influenced the design and implementation of P4, a programming language for specifying the semantics of match action tables that generalizes and improves upon OpenFlow. B4 helped prove the practical utility of SDN in general and OpenFlow in particular, and showed that one could successfully deploy a global WAN using shallow-buffered merchant-silicon switches.

The individuals being recognized are:

Sushant Jain, Alok Kumar, Subhasree Mandal, Joon Ong, Leon Poutievski, Arjun Singh, Venkat Subbaiah Kotla, Jim Wanderer, Junlan Zhou, Min Zhu, Jonathan Zolla, Urs Hölzle, Stephen Stuart, Amin Vahdat, Chi-yao Hong, Mohammad A. Alfares, Rich Alimi, Kondapa Naidu Bollineni, Chandan Bhagat, Sourabh Jain, Jay Kaimal, Jeffrey Liang, Kirill Mendelev, Steve Padgett, Faro Thomas Rabe, Saikat Ray, Malveeka Tewari, Matt Tierney, Monika Zahn, Arda Balkanay, Andrew Ferguson, Puneet Sood, Mukarram Tariq.

The committee comprised of Olivier Bonaventure (UCLouvain, Belgium - chair), Randy Bush (IIJ Research Lab & Arrcus, Inc., Japan), Renata Teixeira (Netflix, USA), and Mythili Vutukuru (Indian Institute of Technology, Bombay, India.


2020: the ns family of network simulators (ns-1, ns-2, and ns-3)
“ns” is a well-known acronym in networking research, referring to a series of network simulators (ns-1, ns-2, and ns-3) developed over the past twenty five years. ns-1 was developed at Lawrence Berkeley National Laboratory (LBNL) between 1995-97 based on an earlier simulator (REAL, written by S. Keshav). ns-2 was an early open source project, developed in the 1997-2004 timeframe and led by collaborators from USC Information Sciences Institute, LBNL, UC Berkeley, and Xerox PARC. A companion network animator (nam) was also developed during this time [Est00]. Between 2005-08, collaborators from the University of Washington, Inria Sophia Antipolis, Georgia Tech, and INESC TEC significantly rewrote the simulator to create ns-3, which continues today as an active open source project.

All of the ns simulators can be characterized as packet-level, discrete-event network simulators, with which users can build models of computer networks with varying levels of fidelity, in order to conduct performance evaluation studies. The core of all three versions is written in C++, and simulation scripts are written directly in a native programming language: for ns-1, in the Tool Command Language (Tcl), for ns-2, in object-oriented Tcl (OTcl), and for ns-3, in either C++ or Python. ns is a full-stack simulator, with a high degree of abstraction at the physical and application layers, and varying levels of modeling detail between the MAC and transport layers. ns-1 was released with a BSD software license, ns-2 with a collection of licenses later consolidated into a GNU GPLv2-compatible framework, and ns-3 with the GNU GPLv2 license. ns-3 [Hen08, Ril10] can be viewed as a synthesis of three predecessor tools: yans [Lac06], GTNetS [Ril03], and ns-2 [Bre00]. ns-3 contains extensions to allow distributed execution on parallel processors, real-time scheduling with emulation capabilities for packet exchange with real systems, and a framework to allow C and C++ implementation (application and kernel) code to be compiled for reuse within ns-3 [Taz13]. Although ns-3 can be used as a general-purpose discrete-event simulator, and as a simulator for non-Internet-based networks, by far the most active use centers around Internet-based simulation studies, particularly those using its detailed models of 4G LTE (led by CTTC) and Wi-Fi systems. The project is now focused on developing models to allow ns-3 to support research and standardization activities involving several aspects of 5G NR, next-generation Wi-Fi, and the IETF Transport Area.

The ns-3-users Google Groups forum has over 9000 members (with several hundred monthly posts), and the developer mailing list contains over 1500 subscribers. Publication counts (as counted annually) in the ACM and IEEE digital libraries, as well as search results in Google Scholar, describing research work using or extending ns-2 and ns-3, continue to increase each year, and usage also appears to be growing within the networking industry and government laboratories. The project’s home page is at, and software development discussion is conducted on the mailing list.

The main authors of ns-1 were (in alphabetical order): Kevin Fall, Sally Floyd, Steve McCanne, and Kannan Varadhan. ns-2 had a larger number of contributors. Space precludes listing all authors, but the following people were leading source code committers to ns-2 (in alphabetical order): Xuan Chen, Kevin Fall, Sally Floyd, Padma Haldar, Ahmed Helmy, John Heidemann, Tom Henderson, Polly Huang, K.C. Lan, Steve McCanne, Giao Nguyen, Venkat Padmanabhan, Yuri Pryadkin, Kannan Varadhan, Ya Xu, and Haobo Yu. A more complete list of ns-2 contributors can be found at:


The ns-3 simulator has been developed by over 250 contributors over the past fifteen years. The original main development team consisted of (in alphabetical order): Raj Bhattacharjea, Gustavo Carneiro, Craig Dowell, Tom Henderson, Mathieu Lacage, and George Riley.

Recognition is also due to the long list of ns-3 software maintainers, many of whom made significant contributions to ns-3, including (in alphabetical order): John Abraham, Zoraze Ali, Kirill Andreev, Abhijith Anilkumar, Stefano Avallone, Ghada Badawy, Nicola Baldo, Peter D. Barnes, Jr., Biljana Bojovic, Pavel Boyko, Junling Bu, Elena Buchatskaya, Daniel Camara, Matthieu Coudron, Yufei Cheng, Ankit Deepak, Sebastien Deronne, Tom Goff, Federico Guerra, Budiarto Herman, Mohamed Amine Ismail, Sam Jansen, Konstantinos Katsaros, Joe Kopena, Alexander Krotov, Flavio Kubota, Daniel Lertpratchya, Faker Moatamri, Vedran Miletic, Marco Miozzo, Hemanth Narra, Natale Patriciello, Tommaso Pecorella, Josh Pelkey, Alina Quereilhac, Getachew Redieteab, Manuel Requena, Matias Richart, Lalith Suresh, Brian Swenson,  Mohit Tahiliani, Cristiano Tapparello, Adrian S.W. Tam, Hajime Tazaki, Frederic Urbani, Mitch Watrous, Florian Westphal, and Dizhi Zhou. The full list of ns-3 authors is maintained in the AUTHORS file in the top-level source code directory, and full commit attributions can be found in the git commit logs.


  • [Bre00] Lee Breslau et al., Advances in network simulation, IEEE Computer, vol. 33, no. 5, pp. 59-67, May 2000.
  • [Est00] Deborah Estrin et al., Network Visualization with Nam, the VINT Network Animator, IEEE Computer, vol. 33, no.11, pp. 63-68, November 2000.
  • [Hen08] Thomas R. Henderson, Mathieu Lacage, and George F. Riley, Network simulations with the ns-3 simulator, In Proceedings of ACM Sigcomm Conference (demo), 2008.
  • [Lac06] Mathieu Lacage and Thomas R. Henderson. 2006. Yet another network simulator. In Proceeding from the 2006 workshop on ns-2: the IP network simulator (WNS2 ’06). Association for Computing Machinery, New York, NY, USA, 12–es.
  • [Ril03] George F. Riley, The Georgia Tech Network Simulator, In Proceedings of the ACM SIGCOMM Workshop on Models, Methods and Tools for Reproducible Network Research (MoMeTools) , Aug. 2003.
  • [Ril10] George F. Riley and Thomas Henderson, The ns-3 Network Simulator. In Modeling and Tools for Network Simulation, SpringerLink, 2010.
  • [Taz13] Hajime Tazaki et al. Direct code execution: revisiting library OS architecture for reproducible network experiments. In Proceedings of the ninth ACM conference on Emerging networking experiments and technologies (CoNEXT ’13). Association for Computing Machinery, New York, NY, USA, 217–228.


The committee comprised of Anja Feldmann (Max-Planck-Institut für Informatik), Srinivasan Keshav (University of Cambridge, chair), and Nick McKeown (Stanford University).

2019: Multipath TCP implementation in the Linux kernel
Multipath TCP [RFC6824] is a recent TCP extension that enables the utilisation of multiple paths to exchange data over a single TCP connection. The development of Multipath TCP started in 2008 when a group of researchers convinced the IETF to work on developing multipath extensions to TCP. At the beginning, the IETF was skeptical. The implementation was developed in parallel with the standardisation work. Early experiments with this implementation revealed that deployed middleboxes were hindering the extensibility of TCP. A detailed measurement study confirmed those problems [Honda11]. Despite the interferences from middleboxes and thanks to the feedback from the implementation, the mptcp working group managed to ensure the deployability of Multipath [NSDI12]. Since then, various research groups have used this implementation to perform measurements, design extensions to Multipath TCP such as new congestion control schemes, ... Citations to RFC6824 or NSDI12 illustrate the impact of Multipath TCP on the research community.
This implementation has also played a key role in the adoption of Multipath TCP within industry [RFC8041,IETFJ16]. Since 2013, Apple uses Multipath TCP on iOS, initially for the Siri application and since last year for any application. The main benefit that they see with Multipath TCP is the ability to support fast handovers from WiFi to cellular when the user is moving. Although Apple developed their own stack, the availability of the Linux implementation reassured them for the stability of the protocol and the possibility of using it on Linux servers. Korea Telecom has convinced Samsung and LG to use this Multipath TCP implementation in all their high-end smartphones to bond WiFi and cellular for premium users. The main benefit that they see with Multipath TCP is the ability of increasing the bandwidth offered to endusers. Another growing use case are the hybrid access networks. To provide higher bandwidth services, a growing number of network operators are deploying solutions to combine their xDSL and 4G networks. This is possible thanks to the availability of a Multipath TCP implementation in the Linux kernel which is the default operating system for xDSL CPE routers. Broadcom and intel include the Linux Multipath TCP implementation in the Software Development Kit that they provide for CPE vendors. Tessares, Soft@home and OVH have deployed hybrid access network services that rely on this implementation. Those hybrid access networks are typically deployed in rural areas where xDSL performance is poor due to line distance.
This implementation is freely available from The development of new features is discussed on the mptcp-dev mailing list,

The main developers were: Christoph Paasch, Sebastien Barre, Gregory Detal.

However, any recognition should also mention the other researchers who have contributed to the code. Based on the published change logs, these include (in alphabetical order) :

Christoph Paasch (Apple), Sébastien Barré (Tessares), Gregory Detal (Tessares), Jaakko Korkeaniemi (Aalto University), Octavian Purdila (intel), Matthieu Baerts (Tessares), Kenjiro Nakayama (Redhat), Mihai P. Andrei (intel), Doru Gucea (intel), Cristina Ciocan (intel), Benjamin Hesmans (Tessares), Per Hurtig Karlstads University), François Finfe (Tessares), Fabrizio Demaria (intel), Fabien Duchêne (UCLouvain), Jaehyun Hwang (Bell Labs and Samsung Electronics), Andreas Seelinger (RWTH Aachen), Thibault Gérondal (Tessares), Stefan Sicleru (intel), Mat Martineau (intel), Peter Krystad (intel), Ossama Othman (intel), Florian Westphal (Redhat), Paolo Abeni (Redhat), Davide Caratti (Redhat), Lavkesh Lahngir, Kostas Peletidis, Irina Tirdea (intel), Viet-Hoang Tran (UCLouvain), Daniel Weber (University of Bonn), Catalin Nicutar (PUB Bucharest), Andrei Maruseac (intel), Andreas Ripke (NEC), Alexander Frömmgen (Google), Zhu Jian, Ycarus, Vlad Dogaru (intel), Valentin Ilie (intel), Tim Froidcoeur (Tessares),Takumi Shinkai (Okayama University), Sebastien Duponcheel (OVH), Savvas Zannettou (Cyprus University of Technology), Patrick Havelange (Tessares), Niels Möller, Niels Laukens (VRT), Kristian Evensen, Kacper Kolodziej, Jorge Boncompte, John Ronan (TSSG), Henrique Cabral, Frank Lenormand, Evelina Dumitrescu, Enhuan Dong,Duncan Eastoe, Christian Pinedo (University of the Basque Country), Cheng Cui (Netapp), Brandon Heller (Stanford University), Baptiste Jonglez (Univ. Grenoble Alpes), Anwar Walid (Nokia Bell Labs).

The 2019 networking systems award committee comprised: Ratul Mahajan (University of Washington), Kun Tan (Huawei), Xiaowei Yang (Duke University).
2018: The Akamai Content Delivery Network (CDN)
The Akamai CDN pioneered the concept of a content distribution network, combining numerous technical innovations with an equally innovative business model that simultaneously met the needs of multiple stakeholders (site owners, ISPs, and users).  Akamai’s technical contributions include a system for mapping clients to the best CDN server, active probing to create a latency model of the Internet, and a dynamic control system that provides load balancing and fault tolerance. In particular, the paper "Consistent Hashing and Random Trees: Distributed Caching Protocols for Relieving Hot Spots on the World Wide Web" (STOC ‘97) provided a deep algorithmic basis, introducing random cache trees for load-balancing, and consistent hashing to minimize churn. With its enormous worldwide scale, the Akamai CDN is an exemplary study in translating research results into a successful operational system.
Contributors: Mike Afergan, Andy Berkheimer (YouTube), Bobby Blumofe (Akamai), Bill Bogstad, Chad Brown, Tim Canfield (Akamai), Alex Caro (Akamai), Rizwan Dhanidina (Akamai), John Dilley (Rafay Systems), Hilla Dishon, Ken Iwamoto (Akamai), Chris Joerg (Akamai), Vinay Kanitkar (Akamai), David Karger (MIT), Brian Kim (Alpine Global), Robert Kleinberg (Cornell University), Sef Kloninger (YouTube), Will Koffel (Google), Leonidas Kontothanassis (Google), Bradley Kuszmaul (Oracle), Tom Leighton (Akamai/MIT), Charles Leiserson (MIT), Danny Lewin (Akamai, died 9/11/2001) , Matthew Levine, Philip Lisiecki (Akamai), Bruce Maggs (Duke University/Akamai), Luke Matkins (LifeStreet), Sean McDermott (Akamai), Gary Miller (Carnegie Mellon University), Erik Nygren (Akamai), Andrew Parker (Netflix), Roberto de Prisco (University of Salerno), Harald Prokop (LevelUp), Hariharan Rahul (MIT), Satish Rao (U. C. Berkeley), Kyle Rose (Akamai), David Shaw (Nasuni), Alex Sherman (Google), Ramesh Sitaraman (UMASS Amherst/Akamai), Scott Smith (Pure Storage), Bin Song (Google), Daniel Stodolsky (YouTube), Ravi Sundaram (Northeastern University), Joel Wein (Google), Chen Lee Welinder, Yoav Yerushalmi (Google)
The 2018 networking systems award committee comprised: Edouard Bugnion (EPFL), Ratul Mahajan (Intentionet), Jeff Mogul (Google, chair), and Ellen Zegura (Georgia Tech)