Probabilistic Loss Ratio Search for Packet Throughput (PLRsearch)
draft-vpolak-bmwg-plrsearch-00

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Benchmarking Working Group                       M. Konstantynowicz, Ed.
Internet-Draft                                             V. Polak, Ed.
Intended status: Informational                             Cisco Systems
Expires: May 17, 2019                                  November 13, 2018

   Probabilistic Loss Ratio Search for Packet Throughput (PLRsearch)
                     draft-vpolak-bmwg-plrsearch-00

Abstract

   This document addresses challenges while applying methodologies
   described in [RFC2544] to benchmarking NFV (Network Function
   Virtualization) over an extended period of time, sometimes referred
   to as "soak testing".  More specifically to benchmarking software
   based implementations of NFV data planes.  Packet throughput search
   approach proposed by this document assumes that system under test is
   probabilistic in nature, and not deterministic.

Status of This Memo

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   This Internet-Draft will expire on May 17, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Model . . . . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Poisson Distribution  . . . . . . . . . . . . . . . . . . . .   3
   4.  Fitting Function Coefficients Distribution  . . . . . . . . .   4
   5.  Algorithm Formulas  . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  Integration . . . . . . . . . . . . . . . . . . . . . . .   5
     5.2.  Optimizations . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Known Implementations . . . . . . . . . . . . . . . . . . . .   5
     6.1.  FD.io CSIT Implementation Specifics . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   10. Normative References  . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Motivation

   Network providers are interested in throughput a device can sustain.

   RFC 2544 assumes loss ratio is given by a deterministic function of
   offered load.  But NFV software devices are not deterministic
   (enough).  This leads for deterministic algorithms (such as MLRsearch
   with single trial) to return results, which when repeated show
   relatively high standard deviation, thus making it harder to tell
   what "the throughput" actually is.

   We need another algorithm, which takes this indeterminism into
   account.

2.  Model

   Each algorithm searches for an answer to a precisely formulated
   question.  When the question involves indeterministic systems, it has
   to specify probabilities (or prior distributions) which are tied to a
   specific probabilistic model.  Different models will have different
   number (and meaning) of parameters.  Complicated (but more realistic)
   models have many parameters, and the math involved can be very
   complicated.  It is better to start with simpler probabilistic model,
   and only change it when the output of the simpler algorithm is not
   stable or useful enough.

   TODO: Refer to packet forwarding terminology, such as "offered load"
   and "loss ratio".

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   TODO: Mention that no packet duplication is expected (or is filtered
   out).

   TODO: Define critical load and critical region earlier.