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A year and some after Switzerland’s plucky protofascist poster art collective cum Trumpist political party, the SVP (Swiss …

I’m writing today from Berlin, after an excellent Passive and Active Measurement conference and a very long but fruitful week in …

I don’t think I’ve ever written a completely optimisic post about politics, but today seems as good a day as any to try. …

My opinion on Billag(1) is complicated. It seems like it could fairly simply be replaced by payments from the general fund, overseen by …

Tomorrow, I’ll take part in a panel discussion at ETH Zürich, entitled “Internet and Trust”. From the flyer for the …


Post Sockets

Moving beyond the BSD sockets API in transport evolution.

The Path Layer

Making the Internet architecture’s implicit path layer explicit.


A tool for active measurement of Internet path transparency.

Measurement and Architecture for a Middleboxed Internet (MAMI)

A 30-month, H2020-funded research project to explore the three-way tussle among the increasing deployment of encryption in the Internet, the evolution of transport protocols, and the provision of network functions by middleboxes.

Smooth Valley Brewing

Making better Swiss beer, twenty liters at a time.

d’Schwiiz inerem Schiffli

A guide to seeing Switzerland with a sea kayak

Selected Publications

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

This measurement study provides an update on deployment status and newly assesses the marginal risk of enabling ECN negotiation by default on client end-systems. Additionally, we dig deeper into causes of connectivity and negotiation issues linked to ECN. We find that about five websites per thousand suffer additional connection setup latency when fallback per RFC 3168 is correctly implemented; we provide a patch for Linux to properly perform this fallback.
In PAM 2015, 2015

Recent Publications

More Publications

(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.


(2017). Post Sockets - Towards an Evolvable Network Transport Interface. Proc. IFIP/IEEE Networking Workshop on Future Internet Transport.


(2017). Principles for Measurability in Protocol Design. ACM Computer Communication Review, April 2017 (Best of CCR 2017).


(2017). Services Provided by IETF Transport Protocols and Congestion Control Mechanisms. RFC 8095.