Considerations When Using Basic OSPF Convergence Benchmarks
RFC 4063

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Network Working Group                                          V. Manral
Request for Comments: 4063                                  SiNett Corp.
Category: Informational                                         R. White
                                                           Cisco Systems
                                                               A. Shaikh
                                                    AT&T Labs (Research)
                                                              April 2005

      Considerations When Using Basic OSPF Convergence Benchmarks

Status of This Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document discusses the applicability of various tests for
   measuring single router control plane convergence, specifically in
   regard to the Open Shortest First (OSPF) protocol.  There are two
   general sections in this document, the first discusses advantages and
   limitations of specific OSPF convergence tests, and the second
   discusses more general pitfalls to be considered when routing
   protocol convergence is tested.

1.  Introduction

   There is a growing interest in testing single router control plane
   convergence for routing protocols, and many people are looking at
   testing methodologies that can provide information on how long it
   takes for a network to converge after various network events occur.
   It is important to consider the framework within which any given
   convergence test is executed when one attempts to apply the results
   of the testing, since the framework can have a major impact on the
   results.  For instance, determining when a network is converged, what
   parts of the router's operation are considered within the testing,
   and other such things will have a major impact on the apparent
   performance that routing protocols provide.

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RFC 4063          Considerations in OSPF Benchmarking         April 2005

   This document describes in detail various benefits and pitfalls of
   tests described in [BENCHMARK].  It also explains how such
   measurements can be useful for providers and the research community.

   NOTE: In this document, the word "convergence" refers to single
   router control plane convergence [TERM].

2.  Advantages of Such Measurement

   o    To be able to compare the iterations of a protocol
        implementation.  It is often useful to be able to compare the
        performance of two iterations of a given implementation of a
        protocol in order to determine where improvements have been made
        and where further improvements can be made.

   o    To understand, given a set of parameters (network conditions),
        how a particular implementation on a particular device will
        perform.  For instance, if you were trying to decide the
        processing power (size of device) required in a certain location
        within a network, you could emulate the conditions that will
        exist at that point in the network and use the test described to
        measure the performance of several different routers.  The
        results of these tests can provide one possible data point for
        an intelligent decision.

        If the device being tested is to be deployed in a running
        network, using routes taken from the network where the equipment
        is to be deployed rather than some generated topology in these
        tests will yield results that are closer to the real performance
        of the device.  Care should be taken to emulate or take routes
        from the actual location in the network where the device will be
        (or would be) deployed.  For instance, one set of routes may be
        taken from an ABR, one set from an area 0 only router, various
        sets from stub area, another set from various normal areas, etc.

   o    To measure the performance of an OSPF implementation in a wide
        variety of scenarios.

   o    To be used as parameters in OSPF simulations by researchers.  It
        may sometimes be required for certain kinds of research to
        measure the individual delays of each parameter within an OSPF
        implementation.  These delays can be measured using the methods
        defined in [BENCHMARK].

   o    To help optimize certain configurable parameters.  It may
        sometimes be helpful for operators to know the delay required
        for individual tasks in order to optimize the resource usage in
        the network.  For example, if the processing time on a router is

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RFC 4063          Considerations in OSPF Benchmarking         April 2005

        found to be x seconds, determining the rate at which to flood