Telnet Linemode option
RFC 1116

Document Type RFC - Proposed Standard (August 1989; No errata)
Obsoleted by RFC 1184
Last updated 2013-03-02
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Network Working Group                    Internet Engineering Task Force
Request for Comments: 1116                 Telnet Linemode Working Group
                                                       D. Borman, Editor
                                                     Cray Research, Inc.
                                                             August 1989

                         Telnet Linemode Option

Status of this Memo

   This RFC describes a proposed elective standard for the Internet
   community.  Hosts on the Internet that support Linemode within the
   Telnet protocol are expected to adopt and implement this standard.
   Distribution of this memo is unlimited.

Overview

   Linemode Telnet is a way of doing terminal character processing on
   the client side of a Telnet connection.  While in Linemode with
   editing enabled for the local side, network traffic is reduced to a
   couple of packets per command line, rather than a couple of packets
   per character typed.  This is very useful for long delay networks,
   because the user has local response time while typing the command
   line, and only incurs the network delays after the command is typed.
   It is also useful to reduce costs on networks that charge on a per
   packet basis.

Table of Contents

   1.   Command Names and Codes                                        2
   2.   Command Meanings                                               3
   2.1  The LINEMODE function                                          3
   2.2  LINEMODE suboption MODE                                        3
   2.3  LINEMODE suboption FORWARDMASK                                 4
   2.4  LINEMODE suboption SLC, Set Local Characters                   5
   2.5  New control characters                                         8
   3.   Default Specification                                          9
   4.   Motivation                                                     9
   5.   Implementation Rules                                          11
   5.1  User Interface                                                11
   5.2  End of line terminators                                       12
   5.3  Output processing                                             12
   5.4  A terminal driver in Telnet?                                  12
   5.5  Setting of Local Characters                                   12
   5.6  FORWARDMASK and SLC_FORW1 and SLC_FORW2                       13
   5.7  Valid and invalid modes and values.                           14
   5.8  Flushing input and output                                     14

Telnet Linemode Working Group                                   [Page 1]
RFC 1116                 Telnet Linemode Option              August 1989

   5.9  State diagram for SLC                                         16
   5.10 Example of a connection                                       17
   6.   Other Telnet options and RFCs                                 20

1.  Command Names and Codes

       LINEMODE        34
           MODE             1
               EDIT             1
               TRAPSIG          2
               MODE_ACK         4
           FORWARDMASK      2
           SLC              3
               SLC_SYNCH        1
               SLC_BRK          2
               SLC_IP           3
               SLC_AO           4
               SLC_AYT          5
               SLC_EOR          6
               SLC_ABORT        7
               SLC_EOF          8
               SLC_SUSP         9
               SLC_EC          10
               SLC_EL          11
               SLC_EW          12
               SLC_RP          13
               SLC_LNEXT       14
               SLC_XON         15
               SLC_XOFF        16
               SLC_FORW1       17
               SLC_FORW2       18

               SLC_DEFAULT      3
               SLC_VALUE        2
               SLC_CANTCHANGE   1
               SLC_NOSUPPORT    0
               SLC_LEVELBITS    3

               SLC_ACK        128
               SLC_FLUSHIN     64
               SLC_FLUSHOUT    32
       EOF            236
       SUSP           237
       ABORT          238

Telnet Linemode Working Group                                   [Page 2]
RFC 1116                 Telnet Linemode Option              August 1989

2.  Command Meanings

2.1 The LINEMODE function

   IAC WILL LINEMODE

      The sender of this command REQUESTS permission to begin sub-
      negotiation of the editing/signaling status.  This should only be
      sent by the client side of the connection.

   IAC WONT LINEMODE

      The sender of this command DEMANDS that sub-negotiation of the
      editing/signaling status not be allowed.

   IAC DO LINEMODE

      The sender of this command REQUESTS that the remote side begin
      subnegotiation of the editing/signaling status.  This should only
      be sent by the server side of the connection.

   IAC DONT LINEMODE

      The sender of this command DEMANDS that the remote side not begin
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