Telnet Linemode Option
RFC 1184

Document Type RFC - Draft Standard (October 1990; No errata)
Obsoletes RFC 1116
Last updated 2013-03-02
Stream IETF
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Stream WG state WG Document
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IESG IESG state RFC 1184 (Draft Standard)
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Network Working Group                               Telnet Working Group
Request for Comments: 1184                             D. Borman, Editor
Obsoletes: RFC 1116                                  Cray Research, Inc.
                                                            October 1990

                         Telnet Linemode Option

Status of this Memo

   This memo describes a Draft Standard for the Internet community, and
   requests discussion and suggestions for improvements.  This RFC
   specifies an IAB standards track protocol for the Internet community.
   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.

Changes from RFC1116:

      Two new mode bits have been added, SOFT_TAB and LIT_ECHO.  These
      bits allow the server to give the client some advise on how to
      echo tabs and non-printable characters.

      Several new special character mappings have been added for cursor
      motion when visual editing is supported.  These are: Move cursor
      one character left/right (SLC_MCL/SLC_MCR), move cursor one word
      left/right (SLC_MCWL/SLC_MCWR), move cursor to begining/end of
      line (SLC_MCBOL/SLC_MCEOL), enter insert/overstrike mode
      (SLC_INSRT/SLC_OVER), erase one character/word to the right
      (SLC_ECR/SLC_EWR), and erase to the beginning/end of the line
      (SLC_EBOL/SLC_EEOL).

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.  Please send comments to the telnet-ietf@cray.com
   mailing list.

Telnet Working Group                                            [Page 1]
RFC 1184                 Telnet Linemode Option             October 1990

Table of Contents

   1.   Command Names and Codes                                        2
   2.   Command Meanings                                               3
   2.1  The LINEMODE function                                          3
   2.2  LINEMODE suboption MODE                                        4
   2.3  LINEMODE suboption FORWARDMASK                                 5
   2.4  LINEMODE suboption SLC, Set Local Characters                   6
   2.5  New control characters                                        10
   3.   Default Specification                                         11
   4.   Motivation                                                    11
   5.   Implementation Rules                                          13
   5.1  User Interface                                                13
   5.2  End of line terminators                                       14
   5.3  Output processing                                             14
   5.4  A terminal driver in Telnet?                                  14
   5.5  Setting of Local Characters                                   14
   5.6  FORWARDMASK and SLC_FORW1 and SLC_FORW2                       15
   5.7  Valid and invalid modes and values                            16
   5.8  Flushing input and output                                     16
   5.9  State diagram for SLC                                         18
   5.10 Example of a connection                                       19
   6.   Other Telnet options and RFCs                                 22
   7.   Security Considerations                                       23
   8.   Author's Address                                              23

1.  Command Names and Codes

       LINEMODE        34
           MODE             1
               EDIT             1
               TRAPSIG          2
               MODE_ACK         4
               SOFT_TAB         8
               LIT_ECHO        16
           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

Telnet Working Group                                            [Page 2]
RFC 1184                 Telnet Linemode Option             October 1990

               SLC_EW          12
               SLC_RP          13
               SLC_LNEXT       14
               SLC_XON         15
               SLC_XOFF        16
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