DetNet Bounded Latency
draft-ietf-detnet-bounded-latency-00

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Last updated 2019-07-24
Replaces draft-finn-detnet-bounded-latency
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DetNet                                                           N. Finn
Internet-Draft                               Huawei Technologies Co. Ltd
Intended status: Informational                            J-Y. Le Boudec
Expires: January 25, 2020                                E. Mohammadpour
                                                                    EPFL
                                                                J. Zhang
                                             Huawei Technologies Co. Ltd
                                                                B. Varga
                                                               J. Farkas
                                                                Ericsson
                                                           July 24, 2019

                         DetNet Bounded Latency
                  draft-ietf-detnet-bounded-latency-00

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

   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 January 25, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Finn, et al.            Expires January 25, 2020                [Page 1]
Internet-Draft           DetNet Bounded Latency                July 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 Latency Bounds . . . . . . . . . . . . .   8
     4.1.  Non-queuing delay bound . . . . . . . . . . . . . . . . .   8
     4.2.  Queuing delay bound . . . . . . . . . . . . . . . . . . .   8
       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
     5.1.  A General Formula . . . . . . . . . . . . . . . . . . . .  11
   6.  Queuing techniques  . . . . . . . . . . . . . . . . . . . . .  12
     6.1.  Queuing data model  . . . . . . . . . . . . . . . . . . .  12
     6.2.  Preemption  . . . . . . . . . . . . . . . . . . . . . . .  14
     6.3.  Time-scheduled queuing  . . . . . . . . . . . . . . . . .  15
     6.4.  Credit-Based Shaper with Asynchronous Traffic Shaping . .  16
       6.4.1.  Flow Admission  . . . . . . . . . . . . . . . . . . .  19
     6.5.  IntServ . . . . . . . . . . . . . . . . . . . . . . . . .  20
     6.6.  Cyclic Queuing and Forwarding . . . . . . . . . . . . . .  22
       6.6.1.  CQF timing sequence . . . . . . . . . . . . . . . . .  23
       6.6.2.  CQF latency calculation . . . . . . . . . . . . . . .  24
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  24
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  24
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  25
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