A Queuing Mechanism with Multiple Cyclic Buffers
draft-dang-queuing-with-multiple-cyclic-buffers-00
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Active Internet-Draft (individual)
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Bingyang Liu
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Joanna Dang
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2021-02-22
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On Agenda |
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detnet at IETF-110
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Network Working Group B. Liu
Internet-Draft J. Dang, Ed.
Intended status: Standards Track Huawei
Expires: August 26, 2021 February 22, 2021
A Queuing Mechanism with Multiple Cyclic Buffers
draft-dang-queuing-with-multiple-cyclic-buffers-00
Abstract
This document presents a queuing mechanism with multiple cyclic
buffers.
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
Task Force (IETF). Note that other groups may also distribute
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 26, 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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described in the Simplified BSD License.
Liu & Dang Expires August 26, 2021 [Page 1]
Internet-Draft February 2021
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
3. Terminology & Abbreviations . . . . . . . . . . . . . . . . . 2
4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 2
5. Queuing with Multiple Cyclic Buffers . . . . . . . . . . . . 3
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
9. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
Network forwarding with bounded latency and zero congestion loss is
important for various industrial applications. The DetNet working
group draft "DetNet Bounded
Latency"[draft-ietf-detnet-bounded-latency] describes requirements
for queuing mechanisms. Among the referenced queuing mechanisms,
Cyclic Queuing and Forwarding (CQF) requires no per-flow dynamic
state at core nodes, which is scalable when the number of flows
grows. To cope with long link delay, more than two cyclic buffers
can be used.
This document discusses the details of the cyclic queuing mechanisms.
We propose a queuing model and mechanism with multiple cyclic
buffers, which can improve bandwidth utilization without sacrificing
latency and jitter.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
3. Terminology & Abbreviations
CQF: Cyclic Queuing and Forwarding
T_c: the length of a cycle
4. Problem Statement
IEEE 802.1Q[IEEE8021TSN] defines CQF. As described in "DetNet
Bounded Latency"[draft-ietf-detnet-bounded-latency], CQF with two
synchronized buffers works as follows. All nodes keep a same cycle
starting time. In a cycle x, Node A sends all packets in a buffer to
Liu & Dang Expires August 26, 2021 [Page 2]
Internet-Draft February 2021
Node B. In the same cycle x, Node B uses a buffer to accumulate all
packets from A, and at the same time sends out the packets that have
already been buffered in cycle x-1. In the next cycle x+1, Node B
sends out all the packets that are received from Node A in cycle x.
If a packet traverses h hops, the maximum latency is (h+1)T_c, and
the minimum latency is (h-1)T_c. The jitter (latency variation)
bound is 2T_c.
| cycle x | cycle x+1 |
Node A +-----------+-----------+
\
\packet
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