Browse Prior Art Database

Internet delay experiments (RFC0889)

IP.com Disclosure Number: IPCOM000003938D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 9 page(s) / 27K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D.L. Mills: AUTHOR

Abstract

This memorandum describes two series of experiments designed to explore the transmission characteristics of the Internet system. One series of experiments was designed to determine the network delays with respect to packet length, while the other was designed to assess the effectiveness of the TCP retransmission-timeout algorithm specified in the standards documents. Both sets of experiments were conducted during the October - November 1983 time frame and used many hosts distributed throughout the Internet system.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 11% of the total text.

Network Working Group D.L. Mills

Request for Comments: 889 December 1983

Internet Delay Experiments

This memo reports on some measurement experiments and suggests some possible

improvements to the TCP retransmission timeout calculation. This memo is

both a status report on the measurements and advice to implementers of TCP.

1. Introduction

This memorandum describes two series of experiments designed to explore

the transmission characteristics of the Internet system. One series of

experiments was designed to determine the network delays with respect to

packet length, while the other was designed to assess the effectiveness of the

TCP retransmission-timeout algorithm specified in the standards documents.

Both sets of experiments were conducted during the October - November 1983

time frame and used many hosts distributed throughout the Internet system.

The objectives of these experiments were first to accumulate experimental

data on actual network paths that could be used as a benchmark of Internet

system performance, and second to apply these data to refine individual TCP

implementations and improve their performance.

The experiments were done using a specially instrumented measurement host

called a Fuzzball, which consists of an LSI-11 running IP/TCP and various

application-layer protocols including TELNET, FTP and SMTP mail. Among the

various measurement packages is the original PING (Packet InterNet Groper)

program used over the last six years for numerous tests and measurements of

the Internet system and its client nets. This program contains facilities to

send various kinds of probe packets, including ICMP Echo messages, process the

reply and record elapsed times and other information in a data file, as well

as produce real-time snapshot histograms and traces.

Following an experiment run, the data collected in the file were reduced

by another set of programs and plotted on a Peritek bit-map display with color

monitor. The plots have been found invaluable in the indentification and

understanding of the causes of netword glitches and other "zoo" phenomena.

Finally, summary data were extracted and presented in this memorandum. The

raw data files, including bit-map image files of the various plots, are

available to other experimenters upon request.

The Fuzzballs and their local-net architecture, called DCN, have about

two-dozen clones scattered worldwide, including one (DCN1) at the Linkabit

Corporation offices in McLean, Virginia, and another at the Norwegian

Telecommunications Adminstration (NTA) near Oslo, Norway. The DCN1 Fuzzball

is connected to the ARPANET at the Mitre IMP by means of 1822 Error Control

Units operating over a 56-Kbps line. The NTA Fuzzball is connected to the

NTARE Gateway by an 1822 interface and then via VDH/HAP operating over a

9.6-Kbps line to SATNET at the Tanum (Sweden) SIMP. For most experiments

described below, these details of the lo...