Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Architecture
draft-ietf-tsvwg-l4s-arch-08

Document Type Active Internet-Draft (tsvwg WG)
Authors Bob Briscoe  , Koen De Schepper  , Marcelo Bagnulo  , Greg White 
Last updated 2020-11-15
Replaces draft-briscoe-tsvwg-l4s-arch
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Stream WG state WG Document (wg milestone: Oct 2020 - Submit "Low Latency,... )
Document shepherd Wesley Eddy
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Send notices to Wesley Eddy <wes@mti-systems.com>
Transport Area Working Group                             B. Briscoe, Ed.
Internet-Draft                                               Independent
Intended status: Informational                            K. De Schepper
Expires: May 19, 2021                                    Nokia Bell Labs
                                                        M. Bagnulo Braun
                                        Universidad Carlos III de Madrid
                                                                G. White
                                                               CableLabs
                                                       November 15, 2020

   Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service:
                              Architecture
                      draft-ietf-tsvwg-l4s-arch-08

Abstract

   This document describes the L4S architecture, which enables Internet
   applications to achieve Low queuing 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 induce very little queuing, aided by
   explicit congestion signaling from 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 the new class of L4S congestion
   controls to coexist with 'Classic' congestion controls 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; protocol features that
   allow network elements to identify L4S traffic; and host support for
   L4S congestion controls.

Briscoe, et al.           Expires May 19, 2021                  [Page 1]
Internet-Draft              L4S Architecture               November 2020

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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   This Internet-Draft will expire on May 19, 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  L4S Architecture Overview . . . . . . . . . . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  L4S Architecture Components . . . . . . . . . . . . . . . . .   7
   5.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  Why These Primary Components? . . . . . . . . . . . . . .  12
     5.2.  What L4S adds to Existing Approaches  . . . . . . . . . .  14
   6.  Applicability . . . . . . . . . . . . . . . . . . . . . . . .  17
     6.1.  Applications  . . . . . . . . . . . . . . . . . . . . . .  17
     6.2.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . .  19
     6.3.  Applicability with Specific Link Technologies . . . . . .  20
     6.4.  Deployment Considerations . . . . . . . . . . . . . . . .  20
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