PIE: A Lightweight Control Scheme To Address the Bufferbloat Problem
draft-ietf-aqm-pie-09

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Internet Draft                                                    R. Pan
Active Queue Management                                    Cisco Systems
Working Group                                               P. Natarajan
Intended Status: Experimental Track                        Cisco Systems
                                                                F. Baker
                                                           Cisco Systems
                                                                G. White
                                                               CableLabs

Expires: February 03, 2017                               August 02, 2016

           PIE: A Lightweight Control Scheme To Address the 
                          Bufferbloat Problem 

                      draft-ietf-aqm-pie-09

Abstract

   Bufferbloat is a phenomenon in which excess buffers in the network
   cause high latency and latency variation. As more and more
   interactive applications (e.g. voice over IP, real time video
   streaming and financial transactions) run in the Internet, high
   latency and latency variation degrade application performance. There
   is a pressing need to design intelligent queue management schemes
   that can control latency and latency variation, and hence provide
   desirable quality of service to users.

   This document presents a lightweight active queue management design,
   called PIE (Proportional Integral controller Enhanced), that can
   effectively control the average queueing latency to a target value.
   Simulation results, theoretical analysis and Linux testbed results
   have shown that PIE can ensure low latency and achieve high link
   utilization under various congestion situations. The design does not
   require per-packet timestamps, so it incurs very little overhead and
   is simple enough to implement in both hardware and software. 

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as
   Internet-Drafts.
 

Pan et al.             Expires February 03, 2017                [Page 1]

INTERNET DRAFT                    PIE                    August 02, 2016

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Copyright and License Notice

   Copyright (c) 2012 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  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3. Design Goals  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   4. The Basic PIE Scheme  . . . . . . . . . . . . . . . . . . . . .  6
     4.1 Random Dropping(ECN Support is described later in this
         document)  . . . . . . . . . . . . . . . . . . . . . . . . .  7
     4.2 Drop Probability Calculation . . . . . . . . . . . . . . . .  8
     4.3 Latency Calculation  . . . . . . . . . . . . . . . . . . . . 10
     4.4 Burst Tolerance  . . . . . . . . . . . . . . . . . . . . . . 10
   5. Optional Design Elements of PIE . . . . . . . . . . . . . . . . 11
     5.1 ECN Support  . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.2 Dequeue Rate Estimation  . . . . . . . . . . . . . . . . . . 11
     5.3 Setting PIE active and inactive  . . . . . . . . . . . . . . 13
     5.4 De-randomization . . . . . . . . . . . . . . . . . . . . . . 14
     5.5 Cap Drop Adjustment  . . . . . . . . . . . . . . . . . . . . 15
   6. Implementation Cost . . . . . . . . . . . . . . . . . . . . . . 15
   7. Scope of Experimentation  . . . . . . . . . . . . . . . . . . . 16
 

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