Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Architecture
draft-ietf-tsvwg-l4s-arch-06

Document Type Active Internet-Draft (tsvwg WG)
Last updated 2020-03-09
Replaces draft-briscoe-tsvwg-l4s-arch
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Transport Area Working Group                             B. Briscoe, Ed.
Internet-Draft                                               Independent
Intended status: Informational                            K. De Schepper
Expires: September 10, 2020                              Nokia Bell Labs
                                                        M. Bagnulo Braun
                                        Universidad Carlos III de Madrid
                                                                G. White
                                                               CableLabs
                                                           March 9, 2020

   Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service:
                              Architecture
                      draft-ietf-tsvwg-l4s-arch-06

Abstract

   This document describes the L4S architecture, which enables Internet
   applications to achieve Low Latency, Low Loss, and Scalable
   throughput (L4S).  The insight on which L4S is based is that the root
   cause of queuing delay is in the congestion controllers of senders,
   not in the queue itself.  The L4S architecture is intended to enable
   *all* Internet applications to transition away from congestion
   control algorithms that cause queuing delay, to a new class of
   congestion controls that utilize explicit congestion signaling
   provided by the network.  This new class of congestion control can
   provide low latency for capacity-seeking flows, so applications can
   achieve both high bandwidth and low latency.

   The architecture primarily concerns incremental deployment.  It
   defines mechanisms that allow both classes of congestion control to
   coexist in a shared network.  These mechanisms aim to ensure that the
   latency and throughput performance using an L4S-compliant congestion
   controller is usually much better (and never worse) than the
   performance would have been using a 'Classic' congestion controller,
   and that competing flows continuing to use 'Classic' controllers are
   typically not impacted by the presence of L4S.  These characteristics
   are important to encourage adoption of L4S congestion control
   algorithms and L4S compliant network elements.

   The L4S architecture consists of three components: network support to
   isolate L4S traffic from classic traffic and to provide appropriate
   congestion signaling to both types; protocol features that allow
   network elements to identify L4S traffic and allow for communication
   of congestion signaling; and host support for immediate congestion
   signaling with an appropriate congestion response that enables
   scalable performance.

Briscoe, et al.        Expires September 10, 2020               [Page 1]
Internet-Draft              L4S Architecture                  March 2020

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on September 10, 2020.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  L4S Architecture Overview . . . . . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  L4S Architecture Components . . . . . . . . . . . . . . . . .   8
   5.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . .  11
     5.1.  Why These Primary Components? . . . . . . . . . . . . . .  11
     5.2.  Why Not Alternative Approaches? . . . . . . . . . . . . .  13
   6.  Applicability . . . . . . . . . . . . . . . . . . . . . . . .  15
     6.1.  Applications  . . . . . . . . . . . . . . . . . . . . . .  15
     6.2.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . .  17
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