Changhoon (Chang) Kim

CTO, Applications

Barefoot Networks

<last-name> dot <full-first-name> on gmail

<handy-first-name> on barefootnetworks

김창훈 金昶勳

I am CTO of Applications at Barefoot Networks and am also working actively for I have been leading various engineering and research projects regarding fully-programmable high-speed networking devices and their applications. Before getting involved with and Barefoot Networks, I had worked at Windows Azure, Microsoft’s cloud-service division and had led engineering and research projects on the architecture, performance, and management of datacenter networks.


I am interested in programmable networking, network monitoring and diagnostics, domain-specific machine architectures, application acceleration, self-configuring/running networks, and debugging and diagnosis of large-scale distributed systems. Many of my engineering and research contributions — including In-band Network Telemetry, Tiny Packet Programs, VL2, Seawall, EyeQ, Ananta, and SEATTLE — are adopted in large production systems and services.


With my collaborators I received a few awards, including best paper awards from top-notch conferences, such as SIGCOMM, NSDI, and FAST. I was the recipient of Microsoft Rockstar Award 2013, an annual recognition for the strongest networking contributions Microsoft-wide. I received PhD in Computer Science at Princeton University, and MS/BS in Computer Engineering at Seoul National University.

CV (available upon request) | Google Scholar 

  • SIGCOMM has recognized the VL2 work with 2019 ACM Test of Time Award. A brief summary of the work according to the award committee is as follows.

"This paper articulated the core design principles that have become the foundation for modern datacenter networks: scalable Clos topologies, randomized load-balanced routing, and virtual networks constructed by decoupling endpoint addresses and locations. By convincingly arguing for these principles, and providing one of the first glimpses into real-world datacenter network traffic characteristics, this paper has had enduring impact on both the practice of datacenter network design and the large body of research on the topic that has followed over the last decade."

Select Talks

Forwarding Plane: An Old New Frontier of Networking Research 

Keynotes at ACM SOSR and ACM/IEEE ANCS, Mar and Jul 2018 respectively [slides]

Programming the Network Data Plane to Accelerate Applications 

QCon, Mar 2018 [video]

In-band Network Telemetry

OVS Orbit -- Ben Pfaff's podcast, Nov 2017 [mp3]


Future of Network Monitoring

Tech Field Day, Jan 2017 [video]


Why Data Plane Will be Programmable For Good

Keynote at APNet, Aug 2017 [slides]

Subtle but Important Benefits of Programmable Data Planes

Keynote at NetPL workshop at SIGCOMM, Aug 2016 [video] [slides]

Select Publications

DistCache: Provable Load Balancing for Large-Scale Storage Systems with Distributed Caching

Zaoxing Liu, Zhihao Bai, Zhenming Liu, Xiaozhou Li, Changhoon Kim, Vladimir Braverman, Xin Jin, and Ion Stoica

USENIX Conference on File and Storage Technologies (FAST), Feb 2019

Best Paper Award

Scaling Distributed Machine Learning with In-Network Aggregation

Amedeo SapioMarco CaniniChen-Yu HoJacob NelsonPanos KalnisChanghoon Kim,
Arvind KrishnamurthyMasoud MoshrefDan R. K. Ports, and Peter Richtárik

Preprint on arXiv, Feb 2019

Fast String Searching on PISA

Theo Jepsen, Daniel Alvarez, Nate Foster, Changhoon Kim, Jeongkeun Lee, Masoud Moshref, and Robert Soulé

ACM SIGCOMM Symposium on Software Defined Networking Research (SOSR), Mar 2019

Generic External Memory For Switch Data Planes

Daehyeok Kim, Yibo Zhu, Changhoon Kim, Jeongkeun Lee, and Srinivasan Seshan

ACM Workshop on Hot Topics in Networks (HotNets), Nov 2018 [video]

NetChain: Scale-Free Sub-RTT Coordination

Xin Jin, Xiaozhou Li, Haoyu Zhang, Nate Foster, Jeongkeun Lee, Robert Soulé, Changhoon Kim, and Ion Stoica

USENIX Symposium on Networked System Design and Implementation (NSDI), Apr 2018  [slides & video]

Best Paper Award

NetCache: Balancing Key-Value Stores with Fast In-Network Caching

Xin Jin, Xiaozhou Li, Haoyu Zhang, Robert Soulé, Jeongkeun Lee, Nate Foster, Changhoon Kim, and Ion Stoica

ACM SIGOPS Symposium on Operating Systems Principles (SOSP), Oct 2017 [slides]

Language-Directed Hardware Design for Network Performance Monitoring

Srinivas Narayana, Anirudh Sivaraman, Vikram Nathan, Prateesh Goyal, Venkat Arun, Mohammad Alizadeh, Vimalkumar Jeyakumar, and Changhoon Kim

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2017 [slides] [video]

Best Paper Award

SilkRoad: Making Stateful Layer-4 Load Balancing Fast and Cheap Using Switching ASICs

Rui MiaoHongyi ZengChanghoon KimJeongkeun Lee, and Minlan Yu
ACM Conference of the Special Interest Group on Data Communication
(SIGCOMM), Aug 2017 [slides[video]

Evaluating the Power of Flexible Packet Processing for Network Resource Allocation

Naveen Kr. Sharma, Antoine Kaufmann, Thomas Anderson, Changhoon Kim, Arvind Krishnamurthy,
Jacob Nelson, and Simon Peter

USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2017 [slides & video]

PISCES: A Programmable, Protocol-Independent Software Switch

Muhammad Shahbaz, Sean Choi, Ben Pfaff, Changhoon Kim, Nick Feamster, Nick McKeown,

and Jennifer Rexford

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2016

Packet Transactions: High-Level Programming for Line-Rate Switches

Anirudh Sivaraman, Alvin Cheung, Mihai Budiu, Changhoon Kim, Mohammad Alizadeh, Hari Balakrishnan, George Varghese, Nick McKeown, and Steve Licking

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2016

FlowRadar: A Better NetFlow for Data Centers

Yuliang Li, Rui Miao, Changhoon Kim, and Minlan Yu.

USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2016


HULA: Scalable Load Balancing Using Programmable Data Planes

Naga Katta, Mukesh Hira, Changhoon Kim, Anirudh Sivaraman, and Jennifer Rexford

ACM SIGCOMM Symposium on Software Defined Networking Research (SOSR), Mar 2016

Programming the Network Dataplane in P4 (in Chinese)

Changhoon Kim, Ron Kao, and Nick McKeown

Communications of the China Computer Federation (CCF), Jul 2016

In-band Network Telemetry via Programmable Data Planes

Changhoon Kim, Anirudh Sivaraman, Naga Katta, Antonin Bas, Advait Dixit, and Lawrence J Wobker

Demo Session for ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2015

Millions of Little Minions: Using packets for low latency network programming and visibility

Vimalkumar Jeyakumar, Mohammad Alizadeh, Yilong Geng, Changhoon Kim, and David Mazières

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2014

Ananta: Cloud scale load balancing

Parveen Patel, Deepak Bansal, Lihua Yuan, Ashwin Murthy, Albert Greenberg, David A Maltz, Randy Kern, Hemant Kumar, Marios Zikos, Hongyu Wu, Changhoon Kim, and Naveen Karri

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2013

EyeQ: Practical Network Performance Isolation at the Network Edge

Vimalkumar Jeyakumar, Mohammad Alizadeh, David Mazières, Balaji Prabhakar, Albert Greenberg,

and Changhoon Kim

USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2013 [slides & video]

Sharing the Data Center Network

Alan Shieh, Srikanth Kandula, Albert G Greenberg, Changhoon Kim, and Bikas Saha

USENIX Symposium on Networked Systems Design and Implementation (NSDI), Mar 2011 [slides & video]


VL2: A Scalable and Flexible Data Center Network

Albert Greenberg, James R Hamilton, Navendu Jain, Srikanth Kandula, Changhoon Kim, Parantap Lahiri,

David A Maltz, Parveen Patel, and Sudipta Sengupta

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2009 [video]

ACM Test of Time Award 2019

Floodless in Seattle: A Scalable Ethernet Architecture for Large Enterprises

Changhoon Kim, Matthew Caesar, and Jennifer Rexford

ACM Conference of the Special Interest Group on Data Communication (SIGCOMM), Aug 2008