Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service: Architecture
draft-ietf-tsvwg-l4s-arch-04
Transport Area Working Group B. Briscoe, Ed.
Internet-Draft CableLabs
Intended status: Informational K. De Schepper
Expires: January 9, 2020 Nokia Bell Labs
M. Bagnulo Braun
Universidad Carlos III de Madrid
G. White
CableLabs
July 8, 2019
Low Latency, Low Loss, Scalable Throughput (L4S) Internet Service:
Architecture
draft-ietf-tsvwg-l4s-arch-04
Abstract
This document describes the L4S architecture for the provision of a
new Internet service that could eventually replace best efforts for
all traffic: Low Latency, Low Loss, Scalable throughput (L4S). It is
becoming common for _all_ (or most) applications being run by a user
at any one time to require low latency. However, the only solution
the IETF can offer for ultra-low queuing delay is Diffserv, which
only favours a minority of packets at the expense of others. In
extensive testing the new L4S service keeps average queuing delay
under a millisecond for _all_ applications even under very heavy
load, without sacrificing utilization; and it keeps congestion loss
to zero. It is becoming widely recognized that adding more access
capacity gives diminishing returns, because latency is becoming the
critical problem. Even with a high capacity broadband access, the
reduced latency of L4S remarkably and consistently improves
performance under load for applications such as interactive video,
conversational video, voice, Web, gaming, instant messaging, remote
desktop and cloud-based apps (even when all being used at once over
the same access link). The insight is that the root cause of queuing
delay is in TCP, not in the queue. By fixing the sending TCP (and
other transports) queuing latency becomes so much better than today
that operators will want to deploy the network part of L4S to enable
new products and services. Further, the network part is simple to
deploy - incrementally with zero-config. Both parts, sender and
network, ensure coexistence with other legacy traffic. At the same
time L4S solves the long-recognized problem with the future
scalability of TCP throughput.
This document describes the L4S architecture, briefly describing the
different components and how the work together to provide the
aforementioned enhanced Internet service.
Briscoe, et al. Expires January 9, 2020 [Page 1]
Internet-Draft L4S Architecture July 2019
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. L4S Architecture Overview . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. L4S Architecture Components . . . . . . . . . . . . . . . . . 7
5. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Why These Primary Components? . . . . . . . . . . . . . . 10
5.2. Why Not Alternative Approaches? . . . . . . . . . . . . . 12
6. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1. Applications . . . . . . . . . . . . . . . . . . . . . . 15
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