Identifying Modified Explicit Congestion Notification (ECN) Semantics for Ultra-Low Queuing Delay
draft-briscoe-tsvwg-ecn-l4s-id-00

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Document Type Active Internet-Draft (individual)
Authors Koen Schepper  , Bob Briscoe  , Ing Tsang 
Last updated 2015-10-19
Replaced by draft-ietf-tsvwg-ecn-l4s-id
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Transport Services (tsv)                                  K. De Schepper
Internet-Draft                                                 Bell Labs
Intended status: Experimental                            B. Briscoe, Ed.
Expires: April 21, 2016                              Simula Research Lab
                                                                I. Tsang
                                                               Bell Labs
                                                        October 19, 2015

 Identifying Modified Explicit Congestion Notification (ECN) Semantics
                      for Ultra-Low Queuing Delay
                   draft-briscoe-tsvwg-ecn-l4s-id-00

Abstract

   This specification defines the identifier to be used on IP packets
   for a new network service called low latency, low loss and scalable
   throughput (L4S).  It is similar to the original (or 'Classic')
   Explicit Congestion Notification (ECN).  'Classic' ECN marking was
   required to be equivalent to a drop, both when applied in the network
   and when responded to by a transport.  Unlike 'Classic' ECN marking,
   the network applies the L4S identifier more immediately and more
   aggressively than drop, and the transport response to each mark is
   reduced and smoothed relative to that for drop.  The two changes
   counterbalance each other so that the bit-rate of an L4S flow will be
   roughly the same as a 'Classic' flow under the same conditions.
   However, the much more frequent control signals and the finer
   responses to them result in ultra-low queuing delay without
   compromising link utilization, even during high load.  Examples of
   new active queue management (AQM) marking algorithms and examples of
   new transports (whether TCP-like or real-time) are specified
   separately.  The new L4S identifier is the key piece that enables
   them to interwork and distinguishes them from 'Classic' traffic.  It
   gives an incremental migration path so that existing 'Classic' TCP
   traffic will be no worse off, but it can be prevented from degrading
   the ultra-low delay and loss of the new scalable transports.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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De Schepper, et al.      Expires April 21, 2016                 [Page 1]
Internet-Draft     ECN Semantics for Low Queuing Delay      October 2015

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on April 21, 2016.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Problem . . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
     1.3.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  L4S Packet Identifier . . . . . . . . . . . . . . . . . . . .   6
     2.1.  L4S Packet Identification Requirements  . . . . . . . . .   6
     2.2.  L4S Packet Identification . . . . . . . . . . . . . . . .   6
     2.3.  L4S Packet Identification with Transport-Layer Awareness    7
     2.4.  The Meaning of CE Relative to Drop  . . . . . . . . . . .   8
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  Alternative Identifiers  . . . . . . . . . . . . . .  12
     A.1.  ECT(1) and CE codepoints  . . . . . . . . . . . . . . . .  12
     A.2.  ECN Plus a Diffserv Codepoint (DSCP)  . . . . . . . . . .  14
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