Benchmarking Terminology for Network Interconnection Devices
RFC 1242

Document Type RFC - Informational (July 1991; No errata)
Updated by RFC 6201
Author Scott Bradner 
Last updated 2013-03-02
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Network Working Group                                 S. Bradner, Editor
Request for Comments: 1242                            Harvard University
                                                               July 1991

      Benchmarking Terminology for Network Interconnection Devices

Status of this Memo

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


   This memo discusses and defines a number of terms that are used in
   describing performance benchmarking tests and the results of such
   tests.  The terms defined in this memo will be used in additional
   memos to define specific benchmarking tests and the suggested format
   to be used in reporting the results of each of the tests.  This memo
   is a product of the Benchmarking Methodology Working Group (BMWG) of
   the Internet Engineering Task Force (IETF).

1.  Introduction

   Vendors often engage in "specsmanship" in an attempt to give their
   products a better position in the marketplace.  This usually involves
   much "smoke & mirrors" used to confuse the user.  This memo and
   follow-up memos attempt to define a specific set of terminology and
   tests that vendors can use to measure and report the performance
   characteristics of network devices.  This will provide the user
   comparable data from different vendors with which to evaluate these

2.  Definition format

        Term to be defined. (e.g., Latency)

                The specific definition for the term.

                A brief discussion about the term, it's application
                and any restrictions on measurement procedures.

        Measurement units:
                The units used to report measurements of this
                term, if applicable.

Benchmarking Methodology Working Group                          [Page 1]
RFC 1242                Benchmarking Terminology               July 1991

                List of issues or conditions that effect this term.

        See Also:
                List of other terms that are relevant to the discussion
                of this term.

3.  Term definitions

3.1  Back-to-back

                Fixed length frames presented at a rate such that there
                is the minimum legal separation for a given medium
                between frames over a short to medium period of time,
                starting from an idle state.

                A growing number of devices on a network can produce
                bursts of back-to-back frames.  Remote disk servers
                using protocols like NFS, remote disk backup systems
                like rdump, and remote tape access systems can be
                configured such that a single request can result in
                a block of data being returned of as much as 64K octets.
                Over networks like ethernet with a relatively small MTU
                this results in many fragments to be transmitted.  Since
                fragment reassembly will only be attempted if all
                fragments have been received, the loss of even one
                fragment because of the failure of some intermediate
                network device to process enough continuous frames can
                cause an endless loop as the sender repetitively
                attempts to send its large data block.

                With the increasing size of the Internet, routing
                updates can span many frames, with modern routers able
                to transmit very quickly.  Missing frames of routing
                information can produce false indications of
                unreachability.  Tests of this parameter are intended
                to determine the extent of data buffering in the

        Measurement units:
                Number of N-octet frames in burst.


        See Also:

Benchmarking Methodology Working Group                          [Page 2]
RFC 1242                Benchmarking Terminology               July 1991

3.2  Bridge

                A system which forwards data frames based on information
                in the data link layer.


        Measurement units:


        See Also:
                bridge/router (3.3)
                router (3.15)

3.3  bridge/router

                A bridge/router is a network device that can selectively
                function as a router and/or a bridge based on the
                protocol of a specific frame.


        Measurement units:


        See Also:
                bridge (3.2)
                router (3.15)

3.4  Constant Load

                Fixed length frames at a fixed interval time.
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