Identifying Modified Explicit Congestion Notification (ECN) Semantics for Ultra-Low Queuing Delay
draft-briscoe-tsvwg-ecn-l4s-id-02

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Transport Services (tsv)                                  K. De Schepper
Internet-Draft                                           Nokia Bell Labs
Intended status: Experimental                            B. Briscoe, Ed.
Expires: May 4, 2017                                 Simula Research Lab
                                                                I. Tsang
                                                         Nokia Bell Labs
                                                        October 31, 2016

 Identifying Modified Explicit Congestion Notification (ECN) Semantics
                      for Ultra-Low Queuing Delay
                   draft-briscoe-tsvwg-ecn-l4s-id-02

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,
   for packets carrying the L4S identifier, the network applies marking
   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
   throughput 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

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De Schepper, et al.        Expires May 4, 2017                  [Page 1]
Internet-Draft     ECN Semantics for Low Queuing Delay      October 2016

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on May 4, 2017.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Problem . . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
     1.3.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   2.  L4S Packet Identifier . . . . . . . . . . . . . . . . . . . .   6
     2.1.  L4S Packet Identification Requirements  . . . . . . . . .   6
     2.2.  L4S Packet Identification . . . . . . . . . . . . . . . .   7
     2.3.  Pre-Requisite Transport Layer Behaviour . . . . . . . . .   8
     2.4.  L4S Packet Identification by Network Nodes with
           Transport-Layer Awareness . . . . . . . . . . . . . . . .   9
     2.5.  The Meaning of CE Relative to Drop  . . . . . . . . . . .  10
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
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