DetNet Bounded Latency
draft-ietf-detnet-bounded-latency-01
DetNet N. Finn
Internet-Draft Huawei Technologies Co. Ltd
Intended status: Informational J-Y. Le Boudec
Expires: May 7, 2020 E. Mohammadpour
EPFL
J. Zhang
Huawei Technologies Co. Ltd
B. Varga
J. Farkas
Ericsson
November 4, 2019
DetNet Bounded Latency
draft-ietf-detnet-bounded-latency-01
Abstract
This document presents a timing model for Deterministic Networking
(DetNet), so that existing and future standards can achieve the
DetNet quality of service features of bounded latency and zero
congestion loss. It defines requirements for resource reservation
protocols or servers. It calls out queuing mechanisms, defined in
other documents, that can provide the DetNet quality of service.
Status of This Memo
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This Internet-Draft will expire on May 7, 2020.
Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
Finn, et al. Expires May 7, 2020 [Page 1]
Internet-Draft DetNet Bounded Latency November 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology and Definitions . . . . . . . . . . . . . . . . . 3
3. DetNet bounded latency model . . . . . . . . . . . . . . . . 4
3.1. Flow creation . . . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Static flow latency calculation . . . . . . . . . . . 4
3.1.2. Dynamic flow latency calculation . . . . . . . . . . 5
3.2. Relay node model . . . . . . . . . . . . . . . . . . . . 6
4. Computing End-to-end Delay Bounds . . . . . . . . . . . . . . 8
4.1. Non-queuing delay bound . . . . . . . . . . . . . . . . . 8
4.2. Queuing delay bound . . . . . . . . . . . . . . . . . . . 9
4.2.1. Per-flow queuing mechanisms . . . . . . . . . . . . . 9
4.2.2. Per-class queuing mechanisms . . . . . . . . . . . . 9
4.3. Ingress considerations . . . . . . . . . . . . . . . . . 10
4.4. Interspersed non-DetNet transit nodes . . . . . . . . . . 11
5. Achieving zero congestion loss . . . . . . . . . . . . . . . 11
6. Queuing techniques . . . . . . . . . . . . . . . . . . . . . 13
6.1. Queuing data model . . . . . . . . . . . . . . . . . . . 13
6.2. Preemption . . . . . . . . . . . . . . . . . . . . . . . 15
6.3. Time-scheduled queuing . . . . . . . . . . . . . . . . . 15
6.4. Credit-Based Shaper with Asynchronous Traffic Shaping . . 16
6.4.1. Delay Bound Calculation . . . . . . . . . . . . . . . 18
6.4.2. Flow Admission . . . . . . . . . . . . . . . . . . . 19
6.5. IntServ . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.6. Cyclic Queuing and Forwarding . . . . . . . . . . . . . . 23
6.6.1. CQF timing sequence . . . . . . . . . . . . . . . . . 24
6.6.2. CQF latency calculation . . . . . . . . . . . . . . . 24
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.1. Normative References . . . . . . . . . . . . . . . . . . 25
7.2. Informative References . . . . . . . . . . . . . . . . . 26
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