Network Working Group S. Bradner, Editor
Request for Comments: 1242 Harvard University
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).
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.
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.
List of other terms that are relevant to the discussion
of this term.
3. Term definitions3.1 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
Number of N-octet frames in burst.
Benchmarking Methodology Working Group [Page 2]RFC 1242 Benchmarking Terminology July 19913.2 Bridge
A system which forwards data frames based on information
in the data link layer.
A bridge/router is a network device that can selectively
function as a router and/or a bridge based on the