Enabling internet-wide deployment of Explicit Congestion Notification

Brian Trammell, Mirja Kuehlewind, Damiano Boppart, Iain Learmonth, Gorry Fairhurst, Richard Scheffnegger

Research output: Contribution to conferenceUnpublished paperpeer-review

17 Citations (Scopus)


Explicit Congestion Notification (ECN) is an TCP/IP extension to signal network congestion without packet loss, which has barely seen deployment though it was standardized and implemented more than a decade ago. On-going activities in research and standardization aim to make the usage of ECN more beneficial. This measurement study provides an update on deployment status and newly the 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. Moreover, we detect and explore a number of cases in which ECN brokenness is clearly path-dependent, i.e. on middleboxes beyond the access or content provider network. Further analysis of these cases can guide their elimination, further reducing the risk of enabling ECN by default.
Original languageEnglish
Publication statusPublished - 19 Mar 2015
EventPassive and Active Measurement Conference - New York, United Kingdom
Duration: 19 Mar 201520 Mar 2015


ConferencePassive and Active Measurement Conference
Country/TerritoryUnited Kingdom
CityNew York

Bibliographical note

PAM 2015


  • ECN
  • transport


Dive into the research topics of 'Enabling internet-wide deployment of Explicit Congestion Notification'. Together they form a unique fingerprint.

Cite this