Priority Switching Scheduler
draft-finzi-priority-switching-scheduler-02

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Last updated 2018-05-30
Stream (None)
Intended RFC status (None)
Formats plain text pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Internet Engineering Task Force                                    Baker
Internet-Draft
Intended status: Informational                                     Finzi
Expires: December 1, 2018                                        Frances
                                                                  Lochin
                                                                Mifdaoui
                                                            ISAE-SUPAERO
                                                            May 30, 2018

                      Priority Switching Scheduler
              draft-finzi-priority-switching-scheduler-02

Abstract

   We detail the implementation of a network scheduler that aims at
   isolating time constrained and elastic traffic flows from best-effort
   traffic.  This scheduler inherits from the priority scheduler (PS)
   but dynamically changes the priority of one or several queues.  Usual
   implementations of rate scheduler schemes (such as WRR, DRR, ...) do
   not allow to efficiently guarantee the capacity dedicated to both AF
   and BE classes as they mostly provide soft bounds.  This means
   excessive margin is used to ensure the capacity requested and this
   impacts the number of additional users that could be accepted in the
   network.  To cope with this issue, this memo presents a credit based
   scheduler mechanism called Priority Switching Scheduler (PSS) that
   allows a more predictable output rate per traffic class.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://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 December 1, 2018.

Baker, et al.           Expires December 1, 2018                [Page 1]
Internet-Draft        Priority Switching Scheduler              May 2018

Copyright Notice

   Copyright (c) 2018 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
   (http://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
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Context and Motivation  . . . . . . . . . . . . . . . . .   2
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.3.  Priority Switching Scheduler in a nutshell  . . . . . . .   3
   2.  Priority Switching Scheduler  . . . . . . . . . . . . . . . .   4
     2.1.  Specification . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Implementation  . . . . . . . . . . . . . . . . . . . . .   7
   3.  Usecase: benefit of using PSS in a Diffserv core network  . .   9
     3.1.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   9
     3.2.  New service offered . . . . . . . . . . . . . . . . . . .  10
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

1.1.  Context and Motivation

   To share the capacity offered by a link, many fair schedulers have
   been developed, such as Weighted Fair Queuing, Weighted Round Robin
   or Deficit Round Robin.  However, with these well-known solutions,
   the output rate of a given queue depends on the amount of traffic
   crossing other queues.  Our proposal aims at reducing the uncertainty
   of the output rate of selected queues, we call them in the following
   controlled queues.  Additionally, compared to previous cited schemes,
   this solution is simpler to implement mainly because it does not
   require a virtual clock, and more flexible thanks to the wide
   possibilities offered by the setting of different priorities.

Baker, et al.           Expires December 1, 2018                [Page 2]
Show full document text