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A couple of months ago, I posted about leaving academia. Two weeks ago, I joined Google as a Site Reliability Engineering (SRE) manager. I’ll be working to keep bits of Google’s technical infrastructure running smoothly, at least once I’ve learned enough about how it works and what all the various switches and levers do to be dangerous. The past two weeks have been a deluge of new things to learn, but I’ve finally got my head far enough above water to reflect on things a bit.


About three years ago I started working part-time (20%) on SCION, a secure, available future Internet architecture. Since I wasn’t around much, I was given a nice easy project that wasn’t on anyone’s critical path: desigining the naming system for SCION (as to that time it was assumed SCION would just use DNS with new RRTYPEs to handle the new address families it introduces). After a few months of part-time thinking about (and rejecting) blockchains and distributed hash tables, I arrived at the design of RAINS, whose recursive acronym ostensibly stands for “RAINS, Another Internet Naming System”, but is really a comment on the weather in Zürich in November.


Looking back over the arc of my career in pseudoacademia, especially over the last three years of digging into transport stack evolution with the MAMI project, there are a few bits of work I’m especially happy to have been a part of. One of these is the inclusion of the spin bit into the QUIC transport protocol. The spin bit was conceived as the minimum useful explicit signal one could add to a transport protocol to improve measurability, the benefit for the overhead is IMO quite worth it.


The IETF uses Jabber for instant messaging during working group meetings, as does the IAB for its own teleconferences and meetings. Since I didn’t really feel like shopping around for a Jabber account, and XMPP integration with Google Talk shut down in the middle of the decade, I decided a few years ago to run my own server, which I pretty much only use for connecting to IETF conference rooms and for chatting with IETF folks as a backchannel during meetings.


I always love going to Schloss Dagstuhl, a retreat for computer scientists in the middle of nowhere in Saarland, Germany. It’s a little difficult to get to, but the train ride (Wallisellen to Saarbrücken via Zürich and Mannheim) is a nice, slow way to step back from whatever context-switching overhead is dominating my days at the moment and start thinking about the theme of the workshop. Last October, I went to what’s probably my last Dagstuhl seminar for a while, spending three days around the billiard table and in the wine cellar figuring out whether there’s anything to be done about Encouraging Reproducibility in Scientific Research of the Internet.


Selected Publications

This document defines the wire image, an abstraction of the information available to an on-path non-participant in a networking protocol. This abstraction is intended to shed light on the implications that increased encryption has for network functions that use the wire image.
RFC 8546, 2019

Drawing on discussions at various venues, we envision a publishing ecosystem for Internet science, supporting publications that are self-contained, interactive, multi-level, open, and collaborative. These publications, which we dub hyperpapers, not only address issues with reproducibility and verifiability of research in Internet science and measurement, but have the potential to increase the impact of our work and change how collaborations work in the field. This note announces initial experiments with Internet measurement hyperpapers with the help of common, tested technologies in data science and software development, and is a call to action to others to come build out this vision with us.
ACM Computer Communication Review, January 2019, 2019

We introduce a lightweight, transport-independent and explicit replacement for TCP timestamps for passive latency measurement in TCP and QUIC. This latency spin signal supports per-flow, single-point and single direction passive measurement of end-to-end RTT using just three bits in the transport protocol header, leveraging the existing dynamics of the vast majority of Internet-deployed transports.
In IMC 2018, 2018

We propose an architectural solution to the blindness of network functions driven by increasing deployment of encryption, by introducing a new “path layer” for transport-independent, in-band signaling between Internet endpoints and network elements on the paths between them, and using this layer to reinforce the boundary between the hop-by-hop network layer and the end-to-end transport layer. We define a path layer header on top of UDP to provide a common wire image for new, encrypted transports. This path layer header provides information to a transport-independent on-path state machine that replaces stateful handling currently based on exposed header flags and fields in TCP; it enables explicit measurability of transport layer performance; and offers extensibility by sender-to-path and path-to-receiver communications for diagnostics and management.
In CNSM 2017, 2017

We seek to generalize the idea of measurement within protocols, e.g., the way in which TCP relies on measurement to drive its end-to-end behavior. Rhetorically, we pose the question “what if the stack had been built with measurability and diagnostic support in mind?”. We start from a set of principles for explicit measurability, and define primitives that, were they supported by the stack, would not only provide a solid foundation for protocol design going forward, but also reduce the cost and increase the accuracy of measuring the network.
ACM Computer Communication Review, April 2017 (Best of CCR 2017), 2017

Recent Publications

More Publications

(2019). The Wire Image of a Network Protocol. RFC 8546.


(2019). Open Collaborative Hyperpapers - A Call to Action. ACM Computer Communication Review, January 2019.

(2018). Three Bits Suffice - Explicit Support for Passive Measurement of Internet Latency in QUIC and TCP. In IMC 2018.

PDF Code

(2018). Tracing Internet Path Transparency. In TMA 2018.


(2017). A Path Layer for the Internet - Enabling Network Operations on Encrypted Protocols. In CNSM 2017.

PDF Slides

(2017). TinyIPFIX for Smart Meters in Constrained Networks. RFC 8272.


(2017). Challenges with Reproducibility. In ACM SIGCOMM Reproducibility 2017.


(2017). Tracking transport-layer evolution with PATHspider. In ANRW 2017.


(2017). copycat - Testing Differential Treatment of New Transport Protocols in the Wild. In ANRW 2017.