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I’m writing today from Berlin, after an excellent Passive and Active Measurement conference and a very long but fruitful week in London for IETF 101, which, for me, came to be dominated by the The Spin Bit. The spin bit is an explicit signal for passive measurability of round-trip time, currently possible in TCP but not in QUIC due to lack of acknowlegment and timestamp information in the clear. It’s an example of a facility designed to fulfill the principles for measurement as a first class function of the network stack we laid out in an article published last year.

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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. Today was an Abstimmungssonntag (“referendum Sunday”) here, and the most important question before Switzerland at the national level was a revocation of the federal government’s authority to levy a compulsory television and radio fee: NoBillag. I’ve already written about this referendum, and how it represented not a mere return of four hundred francs per year to every household, not a mere privatization of a few television and radio stations (one of which I’m listening to right now), but a frontal assault on public media and an attempt to drive the country’s media landscape into low-information territory; in other words noch ein Schritt zum kriechenden Beitritt der Schweiz in die vereinigten Staaten(1).

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My opinion on Billag(1) is complicated. It seems like it could fairly simply be replaced by payments from the general fund, overseen by a non-political body to evaluate applications for funding from SRF and regional providers. What we have in NoBillag, instead, is an attempt to Americanize the Swiss media landscape. Thankfully, I’m not the first to point this out, and I hope I won’t be the last. tl;dr, hey Switzerland, you want Bundesrat Trump?

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Tomorrow, I’ll take part in a panel discussion at ETH Zürich, entitled “Internet and Trust”. From the flyer for the discussion: “The Internet relies on so many layers of trust that one is sometimes surprised that [it] actually works”. This is true, but I suppose that’s a property of any system of sufficient complexity, when viewed by someone who understands it well enough to know how much bubble gum and duct tape is used to hold it together.

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live from the hammock

Internet architecture and Internet-centered research being a global enterprise, I spend between four and seven weeks a year on the road, depending on which year, your definition of road and your definition of week, and a fair amount of time in teleconferences in various timezones in the time in between. One of the fixtures in my calendar is the thrice-annual meeting of the Internet Engineering Task Force (IETF), taking place right now in Chicago. I’ve only missed three such meetings in the past dozen years, and each time I do I attempt to take part via Internet as best I can. Here are my reflections about well it’s working this time around, how it’s improved, and how it could improve further. For in a world where those who steadfastly believe in borders and walls seem to be gaining the upper hand, it seems prudent to prepare to do the work of Internet architecture, engineering, and standardization without the benefit of free movement of the people doing it.

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On the shores of Lake Sarnen in central Switzerland, there’s a museli factory. (Of course there is.) It makes many different kinds of muesli for various markets. One of these is an organic chocolate-amaranth concoction that’s basically the only thing my daughter will eat for dinner this week. I happened to glance at the ingredients, and it occurred to me that there are basically three kinds of people in the world.

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Wasting time at Christmas by burning the site to the ground and starting over seems to be a tradition around here…

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Wow, that year went quickly, on which more later.

I’d wanted to try my hand at brewing for a while, but was put off it by the (accurate) fear than ninety percent of the work was washing bottles and cleaning pots. Then, last winter, as a newly-minted father of a baby with an age measured in weeks, life consisted mainly of sterilizing bottles and not sleeping. I made an offhand comment to the effect that if I was going to spend so much time boiling glass I might as well make beer. Ariane gave me a starter kit, and a year later I’m about seventy liters in and think I have a reasonable clue what I’m doing.

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I’m off to New York in a couple of weeks to present a paper at PAM (which I mentioned here, though sadly the flashy automated demo I was hoping to build was a bit optimistic). The question: “is it safe to turn on ECN on client machines by default, completing the end to end deployment of a simple fifteen year old protocol to give us a better way to signal network congestion than simply dropping packets on the floor?” The answer is: “define safe.” Our key findings:

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In German, there’s a word for an organization which takes its mission very seriously but is adorably incompetent at it: “Kaninchenzüchterverein” (lit. “rabbit-breeding club”). There’s another word for an organization which is bad at what it does because nobody cares: “Saftladen” (lit. “juice shop”).

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Projects

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

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)

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

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