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Concluded WG Explicit Congestion Notification (ecn)

Note: The data for concluded WGs is occasionally incorrect.

WG Name Explicit Congestion Notification
Acronym ecn
Area Transport Area (tsv)
State Concluded
Charter charter-ietf-ecn-01 Approved
Document dependencies
Personnel Chairs Dr. K. K. Ramakrishnan, Sally Floyd

Final Charter for Working Group

Internet routers that are capable of active queue management (e.g., RED
gateways) detect congestion before the queue overflows, and therefore
are no longer limited to packet drops as an indication of congestion.
Explicit Congestion Notification (ECN) is described in Internet draft
draft-kksjf-ecn-00.txt [RF97].  With ECN, a router could notify
ECN-capable end nodes of congestion by setting the ECN bit in the
packet header instead of dropping the packet at the router.

The incorporation of ECN in the Internet would benefit applications and
transports that are sensitive to the loss (and/or the subsequent
retransmission delay) of a single packet.  The range of applications
that should benefit includes short web transfers, interactive telnet
traffic, realtime audio and video traffic, and reliable multicast.  For
many of these applications, depending on packet loss as a normal
congestion notification mechanism is less than optimal.

The main purpose of this BOF is to collect together people already
working on ECN to discuss outstanding IP, TCP, and UDP-related issues
regarding ECN.  The BOF will also serve as an introduction to the
issues for other members of the IETF community.

We believe that one reasonably straightforward function of the meeting
would be as a forum to discuss the additions needed for ECN support in
TCP.  This is already under discussion informally, as there are several
independent implementations of ECN in IP and in TCP for experimental
purposes in testbeds. We hope to also discuss issues of
interoperability and the motivation for the 2nd bit in the ECN proposal
to aid gradual introduction of ECN functionality. The meeting could
also begin a discussion of the issues involved in adding ECN support to
UDP and UDP-based applications.

[RF97] Ramakrishnan, K.K., and Floyd, S., A Proposal to add Explicit
Congestion Notification (ECN) to IPv6 and to TCP . Internet draft
draft-kksjf-ecn-00.txt, work in progress. November 1997.

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