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Telnet Protocol Specification (RFC0854)

IP.com Disclosure Number: IPCOM000003901D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 13 page(s) / 37K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Postel: AUTHOR [+2]

Abstract

The purpose of the TELNET Protocol is to provide a fairly general, bi-directional, eight-bit byte oriented communications facility. Its primary goal is to allow a standard method of interfacing terminal devices and terminal-oriented processes to each other. It is envisioned that the protocol may also be used for terminal-terminal communication ("linking") and process-process communication (distributed computation).

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 8% of the total text.

Network Working Group J. Postel

Request for Comments: 854 J. Reynolds

ISI

Obsoletes: NIC 18639 May 1983

TELNET PROTOCOL SPECIFICATION

This RFC specifies a standard for the ARPA Internet community. Hosts on

the ARPA Internet are expected to adopt and implement this standard.

INTRODUCTION

The purpose of the TELNET Protocol is to provide a fairly general,

bi-directional, eight-bit byte oriented communications facility. Its

primary goal is to allow a standard method of interfacing terminal

devices and terminal-oriented processes to each other. It is

envisioned that the protocol may also be used for terminal-terminal

communication ("linking") and process-process communication

(distributed computation).

GENERAL CONSIDERATIONS

A TELNET connection is a Transmission Control Protocol (TCP)

connection used to transmit data with interspersed TELNET control

information.

The TELNET Protocol is built upon three main ideas: first, the

concept of a "Network Virtual Terminal"; second, the principle of

negotiated options; and third, a symmetric view of terminals and

processes.

1. When a TELNET connection is first established, each end is

assumed to originate and terminate at a "Network Virtual Terminal",

or NVT. An NVT is an imaginary device which provides a standard,

network-wide, intermediate representation of a canonical terminal.

This eliminates the need for "server" and "user" hosts to keep

information about the characteristics of each other's terminals and

terminal handling conventions. All hosts, both user and server, map

their local device characteristics and conventions so as to appear to

be dealing with an NVT over the network, and each can assume a

similar mapping by the other party. The NVT is intended to strike a

balance between being overly restricted (not providing hosts a rich

enough vocabulary for mapping into their local character sets), and

being overly inclusive (penalizing users with modest terminals).

NOTE: The "user" host is the host to which the physical terminal

is normally attached, and the "server" host is the host which is

normally providing some service. As an alternate point of view,

RFC 854 May 1983

applicable even in terminal-to-terminal or process-to-process

communications, the "user" host is the host which initiated the

communication.

2. The principle of negotiated options takes cognizance of the fact

that many hosts will wish to provide additional services over and

above those available within an NVT, and many users will have

sophisticated terminals and would like to have elegant, rather than

minimal, services. Independent of, but structured within the TELNET

Protocol are v...