Internet Architecture Board


IAB Workshop on Stack Evolution in a Middlebox Internet (SEMI) 2015

Home»Activities»Workshops»IAB Workshop on Stack Evolution in a Middlebox Internet (SEMI) 2015

26-27 January 2015 – ETH Zürich, Switzerland

The Internet’s transport layer has ossified, squeezed between narrow interfaces (from BSD sockets to pseudo-transport over HTTPS) and increasing in-network modification of traffic by middleboxes that make assumptions about the protocols running through them. This ossification makes it difficult to innovate in the transport layer, through the deployment of new protocols or the extension of existing ones. At the same time, emerging applications require functionality that existing protocols can provide only inefficiently, if at all.

To begin to address this problem, the Internet Architecture Board (IAB), within the scope of its IP Stack Evolution Program, is organizing a workshop to discuss approaches to de-ossifying transport, especially with respect to interactions with middleboxes and new methods for implementing transport protocols. Recognizing that the end-to-end principle has long been compromised, we start with the fundamental question of matching paths through the Internet with certain characteristics to application and transport requirements. Which paths through the Internet are actually available to applications? Which transports can be used over these paths? How can applications cooperate with network elements to improve path establishment and discovery? Can common transport functionality and standardization help application developers to implement and deploy such approaches in today’s Internet? Could cooperative approaches give us a way to rebalance the Internet back toward its end-to-end roots?


For this workshop we would like to consider topics that speak to these questions, including the following:

  • Development and deployment of transport-like features in application-layer protocols
  • Methods for discovery of path characteristics and protocol availability along a path
  • Methods for middlebox detection and characterization of middlebox behavior and functionality
  • Methods for NAT and middlebox traversal in the establishment of end-to-end paths
  • Mechanisms for cooperative path-endpoint signaling, and lessons learned from existing approaches
  • Economic considerations and incentives for cooperation in middlebox deployment

We will explicitly focus on approaches that are incrementally deployable within the present Internet.

The outcome of the workshop will be architectural and engineering guidance on future work in the area, published as an IAB workshop report, based on discussion of proposed approaches; future work will be pursued within the IAB Stack Evolution Program. We will also explore possible areas for standardization, e.g. new protocols that separate signaling to and from on-path devices and common transport semantics from the rest of the transport protocol; and for general guidance, e.g. how transports as well as middleboxes can be designed and deployed to achieve these goals.

Position Papers of Attendees

Workshop Slides

Workshop Transcription

Additional Reading

Submission Instructions

Attendance at the workshop is by invitation. Prospective participants are invited to submit short (i.e., about two pages) position papers outlining their views on one or more topics related to the scope of the workshop.  Position papers will be published on the IAB website at

Submissions accepted at:
Title Registration Deadline: 31 October 2014
Final Submission Deadline: 7 November 2014
Notification Deadline: 24 November 2014
Workshop Dates: 26-27 January 2015

Travel Grants

The Internet Society will sponsor a very limited number of travel grants (including economy class airfare, hotel costs and incidental expenses) for invited attendees who have no other source of travel funding.


Date Time Description
Mon 26 09:00 – 09:15 Welcome; workshop format and goals
09:15 – 10:00 Introductions: one minute per person, based on questionnaire
10:00 – 10:45 The bigger picture: what is the problem? how did we get here?
10:45 – 11:15 Coffee Break, HG Foyer E Süd
11:15 – 12:45 The bigger picture: discussion
12:45 – 14:15 Lunch, FoodLab, CAB
14:15 – 15:30 The role and rule of middleboxes: intro and discussion
15:30 – 16:00 Coffee break, HG Foyer E Süd
16:00 – 17:45 Unbreaking transport: lightning talks and discussion
17:45 – 18:00 Close of day 1: discussion wrapup, Day 2 agenda setting
19:30 Social Dinner, Le Dezaley, Römergasse 7
Tue 27 09:00 – 09:15 Agenda Bash
09:15 – 10:45 Discussion Slot One (topic TBD)
10:45 – 11:00 Coffee Break, HG Foyer E Süd
11:00 – 13:00 Discussion Slot Two (topic TBD)
13:00 – 14:30 Lunch, Dozentenfoyer, HG
14:30 – 15:30 Next steps, concluding remarks, and action items
15:30 – 16:00 Coffee Break, HG Foyer E Süd
16:00 – 18:00 Breakout (time to start work on action items)


The workshop will take place at the ETH Zurich central campus main building, Rämistrasse 101, 8006 Zürich, Switzerland.

Public transport in Zurich is the recommend way to get around. The main building is located directly at the ETH-Universitätsspital tram stop on lines 6, 9, and 10, and at the top of the Polybahn funicular railway (middle right of

If cost is of any concerns, taxis are generally to be avoided in Zurich; a taxi from the airport into the city will cost about CHF 60.- to CHF 80.- one way, depending on traffic. Further parking in the city center is severely limited and quite expensive, as well, so it’s not recommended to rent a car, either.


There are no block reservations for the workshop; the following hotels (~CHF 150-250 a night) are close enough to the venue to walk:

Hotel Marta **
Zähringerstrasse 36
+41 44 269 95 95

Hotel Plattenhof ***
Plattenstrasse 26
+41 44 251 19 10

Hotel Sunnehus ***
Sonneggstrasse 17
+41 44 250 27 27

Hotel Du Théâtre ***
Seilergraben 69
+41 44 267 26 70

Central Plaza Hotel ****
Central 1
+41 44 256 56 56

Technical Program Committee

  • Gorry Fairhurst, University of Aberdeen, UK
  • Matthew Ford, Internet Society, UK
  • Joe Hildebrand, Cisco, USA
  • Mirja Kühlewind, ETH Zurich, Switzerland
  • Eliot Lear, Cisco, Switzerland
  • Martin Stiemerling, University of Applied Science Darmstadt, Germany
  • Brian Trammell, ETH Zurich, Switzerland

Sponsored by the Internet Architecture Board, the Internet Society, and ETH Zürich. Mirja Kühlewind and Brian Trammell, General Chairs.