IETF101 in London, March 17-23

Last month, the IETF returned to the Hilton Metropole near Paddington Station in London for its 101st meeting.

Hello, London!

While it is always nice to go to an IETF meeting in Europe (and therefore suffer less from jet-lag), in this specific hotel the challenge is to find your way around and actually make it to your meeting in time. The meeting room are distributed over three “wings” in the first as well as ground floors as well as in the upper third and “lower third level” (i.e., the sub-basement, next to the Underground), with a less than optimal elevator configuration:

However, the meeting itself was very productive, despite the labyrinth! As is now customary, the week started early on Saturday and Sunday already with the Hackathon where MAMI was present with two projects and a total of 6 people working on Scalable, Privacy-preserving In-Network Measurement (i.e., the QUIC Latency Spin Bit) and a testbed for 1-bit optimisations for the mobile access network based on the Loss-Latency tradeoff.

Monday, we mainly focused on transport topics with a presentation of the soon-to-be-finished AccECN TCP extension in tcpm, an interesting discussion about framing in QUIC (i.e. whether or not to use DTLS as QUIC’s wire image), and a general discussion about TCP encapsulation in tsvarea.

On Tuesday both of the research groups that have grown out of the MAMI project met: theMeasurement and Analysis for Protocols (MAP) and the proposed Path Aware Networking (PAN) research groups. MAPRG’s two and a half hour slot contained many interesting presentations, covering both papers from, e.g., IMC as well as “previews” of work presented at PAM 2018 the following week in Berlin.

PANRG met for the third time as a proposed RG, which means that the process of actually forming the group officially is underway now. The meeting had a productive discussion and a lot of positive feedback, indicating that there is interest in continuing work in the group. There seem to be two broad areas of research the group will tackle going forward: exploring how to add “path awareness” to the Internet architecture (in the vein of the PLUS work pursued by the MAMI project), and continuing work on various not-yet-ready-for-standardization techniques to use path information at the transport layer.

The MAMI project, together with the H2020 NEAT project and engineers and researchers from Apple, the University of Glasgow, and TU Berlin, proposed a new architecture for the Transport Services working group, and an abstract interface for that architecture based in large part on MAMI’s Post Sockets and flexible transport layer work. These drafts were adopted by the TAPS working group, and will form the basis of a new standard abstract API for the transport layer.

The new TAPS cabal, working out the details after the adoption of the new architecture drafts. (Thanks Colin Perkins for the photo!)

MAMI was also busy in TLS, presenting a proposal to extend the DTLS header and discussing the nuances of the DTLS connection Id encoding, and in ACME where we asked for WGLC of the STAR document.

The “main event” for the project, so to say, took place on Thursday morning with a discussion of the QUIC Spin Bit, a facility for supporting passive round-trip time measurement despite the encryption of the QUIC header. This discussion took the majority of a two and a half hour session, and was quite lively: for the first time in our experience at an IETF meeting, the microphones at an IETF meeting had to be moved to keep the line from running out the door.

“How many engineers does it take to spin one bit?”

While the working group still could not come to consensus to add the spin bit directly to the protocol at this time, the outcome was a good one for the project (and for the concept of explicit measurability and in our opinion, for the Internet at large): one bit has been reserved for experimentation with the spin bit, with a directive to reserve a further two for experimentation with additional signaling such as the Valid Edge Counter (VEC) presented at the meeting, with a draft to be published under working group change control for coordinating larger-scale experimentation.

All in all, it was a great week in London, and we’re already looking forward to July’s IETF 102 meeting in Montreal!