I've moved to Nefeli Networks

I work on computer networks at large, with projects in reconfigurable (hybrid circuit/packet) datacenter networks, video/content delivery, network architecture, and mobile. My thesis work is on reconciling interactions between multiple network control loops (e.g., between layers (Etalon), between companies (VDX), or for scalability (VDN)). More detailed information about my work can be found in my research statement.

I completed my PhD at CMU, advised by Srini Seshan. Before CMU, I received my B.A. in Computer Science and Japanese at Dartmouth College, advised by Andrew Campbell and Tanzeem Choudhury in CS, and James Dorsey in Japanese. I received my M.Eng. in Computer Science at Cornell University, advised by Daniel Freedman.

Network system operation is typically divided into control and data planes--- while the data plane is responsible for processing individual messages or packets, the control plane computes the configuration of devices and optimizes system-wide performance. Unfortunately, the control plane of each network system or protocol layer typically operates independently, resulting in poor interactions between control planes across systems. I categorize such systems using four general control plane coordination mechanisms that can overcome these problems, based on how much information can be shared between control planes. If no information is shared, control planes simply "react" to data plane changes as a rudimentary form of coordination. If all information can be shared, "transparency" in decision making can remove most poor interactions. In many scenarios, however, only some information can be shared (e.g., between control planes running in different companies). Coordination in these scenarios is more specialized; control planes with separate data plane resources can use "priority ranking" (i.e., providing a list of preferences for resources without needing to show how those preferences were decided; e.g., BGP routing between ISPs), and control planes with shared data plane resources can use "hierarchical partitioning" (i.e., making coarse-grained decisions globally, and fine-grained decisions locally; e.g., internet-wide BGP + OSPF routing).

While systems utilizing control plane coordination exist today, they have been designed in an ad hoc fashion. I propose a set of recipes that show when it's appropriate to use different coordination mechanisms, based on key properties (information sharing and shared resources) in varied scenarios (layering, administrative separation, and internet-scale systems).

I use these recipes to guide system design in a variety of contexts, as a case study in control plane coordination. Transparency can boost performance in layered systems, as I show with Etalon, in the context of reconfigurable datacenters. Priority ranking can better optimize for cost in administratively separate systems, as I show with VDX, in the context of content brokering. Hierarchical partitioning can improve responsiveness in internet-scale systems, as I show with VDN, in the context of live video streaming. Through this case study we find that these coordination mechanisms not only solve a variety of problems, but can be efficiently implemented.

Document: Matthew K. Mukerjee. Eliminating Adverse Control Plane Interactions in Independent Network Systems.

Slides: pdf keynote

As datacenter networking demands have increased, CMOS manufactures have struggled to build switches with simultaneously higher bandwidth and port count. Thus, researchers have proposed augmenting datacenters with very high bandwidth circuit technologies (e.g., 60GHz wireless, optics) to add bandwidth on demand. Modifying circuits, however, has a non-trivial reconfiguration delay, leading to end-to-end challenges. In this work, we identify three key challenges: rapid bandwidth fluctuation, poor demand estimation, and difficult-to-schedule workloads. These challenges all derive from assumptions made by the application and endhost stack about the network. Using cross-layer knowledge, we solve these problems directly with: dynamic in-network queue resizing to mask bandwidth fluctuations, proper demand estimation using endhost stack ADUs, and rewriting application logic for easier-to-schedule demand. We evaluate the efficacy of these solutions by building Etalon, an open-source reconfigurable datacenter emulator for use on public testbeds, finding they can improve circuit utilization by 2x, flow-completion time by 8x, and HDFS write times by 9x.

Publication (NSDI '20): Matthew K. Mukerjee, Christopher Canel, Weiyang Wang, Daehyeok Kim, Srinivasan Seshan, Alex C. Snoeren. Adapting TCP for Reconfigurable Datacenter Networks.

Slides: pdf keynote

Etalon source code: github

Various trends are reshaping Internet video delivery: exponential growth in video traffic, increasing expectations of high video quality of experience (QoE), and the proliferation of varied CDN deployments (e.g., cloud computing-based, content provider-owned datacenters, and ISP-owned CDNs). More fundamentally, content providers are shifting delivery from a single CDN to multiple CDNs, through the use of a content broker. In our work, we show brokers invalidate many traditional delivery assumptions by not communicating their decisions with CDNs (e.g., shifting traffic between CDNs mid-stream invalidates short- and long-term CDN traffic prediction). Using data from both a CDN and a broker, we provide the first analysis of these issues, and design a proper marketplace-like interface (VDX) that provides better client performance and fairly pays CDNs based on their per-cluster delivery costs.

Publication (CoNEXT '17): Matthew K. Mukerjee, Ilker Nadi Bozkurt, Devdeep Ray, Bruce Maggs, Srinivasan Seshan, Hui Zhang. Redesigning CDN-Broker Interactions for Improved Content Delivery.
Best Paper Award

Publication (HotNets '16): Matthew K. Mukerjee, Ilker Nadi Bozkurt, Bruce Maggs, Srinivasan Seshan, Hui Zhang. The Impact of Brokers on the Future of Content Delivery.

Slides (CoNEXT): pdf keynote

Slides (HotNets): pdf keynote

Live video delivery is difficult to control due to failures, flash crowds, and under-provisioning at Internet-scale. Traditional caching-based solutions are not helpful due to the live aspect. Pure centralization in the wide-area is not practical due to the simultaneous need of high availability, low latency, and highly optimized quality. We design a system, VDN, that combines the quality benefits of centralized optimization with the high availability and low latency of distributed control, which we dub hybrid control. Using large-scale simulation and a wide-area testbed, we show that VDN can offer ~2x improvement in quality over today's DNS-based systems and ~100ms join times, while providing CDN operators expressive policy management.

Publication (SIGCOMM '15): Matthew K. Mukerjee, David Naylor, Junchen Jiang, Dongsu Han, Srinivasan Seshan, Hui Zhang. Practical, Real-time Centralized Control for CDN-based Live Video Delivery.

Slides: pdf keynote

How can we incorporate commodity (toy / < $300) electroencephalography (EEG) headsets into meaningful mobile applications? We build NeuroPhone, a brain-powered address book, to provide a cursory glance into this seemingly Sci-Fi future. A phone presents pictures of contacts, and the user is told to anticipate the picture of the person they wish to call. When the picture appears, their brain elicits a P300 response recognized by the EEG headset, initiating the call.

Publication (SIGCOMM 2010 workshop MobiHeld): Campbell, A. T., T. Choudhury, S. Hu, H. Lu, M. K. Mukerjee, M. Rabbi, R. D. S. Raizada. NeuroPhone: Brain-Mobile Phone Interface using a Wireless EEG Headset.

I collaborate with musicians around the world on YouTube. These days most projects are with my jazz-fusion video game music band Tetrimino.