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TCP Extension for High-Speed Paths (RFC1185)

IP.com Disclosure Number: IPCOM000001998D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 17 page(s) / 45K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

V. Jacobson: AUTHOR [+3]

Abstract

TCP uses positive acknowledgments and retransmissions to provide reliable end-to-end delivery over a full-duplex virtual circuit called a connection [Postel81]. A connection is defined by its two end points; each end point is a "socket", i.e., a (host,port) pair. To protect against data corruption, TCP uses an end-to-end checksum. Duplication and reordering are handled using a fine-grained sequence number space, with each octet receiving a distinct sequence number.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 7% of the total text.

Network Working Group V. Jacobson

Request for Comments: 1185 LBL

R. Braden

ISI

L. Zhang

PARC

October 1990

TCP Extension for High-Speed Paths

Status of This Memo

This memo describes an Experimental Protocol extension to TCP for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "IAB

Official Protocol Standards" for the standardization state and status

of this protocol. Distribution of this memo is unlimited.

Summary

This memo describes a small extension to TCP to support reliable

operation over very high-speed paths, using sender timestamps

transmitted using the TCP Echo option proposed in RFC-1072.

1. INTRODUCTION

TCP uses positive acknowledgments and retransmissions to provide

reliable end-to-end delivery over a full-duplex virtual circuit

called a connection [Postel81]. A connection is defined by its two

end points; each end point is a "socket", i.e., a (host,port) pair.

To protect against data corruption, TCP uses an end-to-end checksum.

Duplication and reordering are handled using a fine-grained sequence

number space, with each octet receiving a distinct sequence number.

The TCP protocol [Postel81] was designed to operate reliably over

almost any transmission medium regardless of transmission rate,

delay, corruption, duplication, or reordering of segments. In

practice, proper TCP implementations have demonstrated remarkable

robustness in adapting to a wide range of network characteristics.

For example, TCP implementations currently adapt to transfer rates in

the range of 100 bps to 10**7 bps and round-trip delays in the range

1 ms to 100 seconds.

However, the introduction of fiber optics is resulting in ever-higher

transmission speeds, and the fastest paths are moving out of the

domain for which TCP was originally engineered. This memo and RFC-

1072 [Jacobson88] propose modest extensions to TCP to extend the

domain of its application to higher speeds.

There is no one-line answer to the question: "How fast can TCP go?".

The issues are reliability and performance, and these depend upon the

round-trip delay and the maximum time that segments may be queued in

the Internet, as well as upon the transmission speed. We must think

through these relationships very carefully if we are to successfully

extend TCP's domain.

TCP performance depends not upon the transfer rate itself, but rather

upon the product of the transfer rate and the round-trip delay. This

"bandwidth*delay product" measures the...