RFC339

NETWORK WORKING GROUP R.Thomas REQUEST FOR COMMENTS #339 BBN N.I.C. #9932 May 5,1972

         MLTNET - A "MULTI-TELNET" SUBSYSTEM FOR TENEX

INTRODUCTION

MLTNET is a TELNET-like facility for TENEX which enables a user to control a number of jobs, running on different ARPANET hosts. It multiplexes the user's local console among the remote jobs. MLTNET is useful in applications which require coordinated behavior of several network hosts. In particular, we have found it helpful in debugging programs which make use of the network. The MLTNET program is designed to be easy to use and, while used in remote mode, to be as transparent as possible to the user. It is somewhat less sophisticated than the TENEX user-TELNET program. MLTNET is currently a subsystem on the BBN- TENEX host.

USING MLTNET

MLTNET operates in two modes:

Local Mode Operation:

    When in local mode MLTNET interprets input types by the
    user as commands to it. Commands consist of a mnemonic
    command name followed by zero or more parameters.
    Included in the commands recognized by MLTNET are ones
    which enable the user to associate a name of his choice
    with a connection to an ARPANET site, to establish a
    connection with a named site, to list the network status
    as seen from the user's TENEX etc.

Remote Mode Operation

    When operating in remote mode MLTNET makes the user's
    console appear to be directly connected to a remote
    site. It transmits input typed by the user to the
    remote site and prints output recieved from the remote
    site. Output received from a remote site while the user
    is in local mode or is interacting with another remote
    site is buffered for the user by MLTNET.

    MLTNET has been designed to be transparent to the user
    while operating in remote mode. In particular, when in
    remote mode it transmits user-types ^C (CONTROL-C, the
    TENEX "attention" character) and ^T (CONTROL-T, the
    TENEX "time used query" character) to the remote site.

    When in local mode ^C and ^T have their usual TENEX
    effect.

    Occasinally a user may find it necessary to modify the
    characteristics of a connection to a particular remote
    site. For example, he may want to have MLTNET echo
    typed input as it is transmitted. Or, he may be using a
    remote host which requires both upper and lower case
    characters from a local terminal which has only upper
    case; in such a case he would want MLTNET to transmit
    upper and lower case as appropriate. In remote mode
    operation MLTNET recognizes "!" as an escape character
    and interprets the character following it as a command
    to change the characterristics of the connection currently
    in use. Commands recognized by MLTNET in remote mode
    are summerized in the next section. To have MLTNET
    transmit "!" to the remote site the user types "!!".

MLTNET Command Summary

Local Mode Commands

MLTNET uses the character "<" to signal the user that it is in local mode ready to accept input. Commands and command parameters may be editted as they are input.The character ^A (CONTROL-A) deletes the last character input. In response to a ^A MLTNET types " deleted. The character ^R (CONTROL-R) causes the input string as collected so far to be retyped (with all editting carried out). MLTNET responds to the character RUBOUT (octal 177) by aborting the current input collecting operation and typeing the ready character "<". The ALTMODE character (octal 175) may be used to invoke command recognition and completion. If insufficient information is availble to recognize an input string as a command MLTNET responds to ALTMODE by ringing the terminal bell. Any prefix which uniquely identifies a command is recognized as that command by MLTNET.

In the following, <name> and <site> denote command parameters. They are strings terminated by a space or carriage return. <name> is a user chosen string of 14 characters or less; site is either the name of an ARPANET host or the string "LOCAL".

The commands recognized by MLTNET in local mode are:

ASSIGN:

    syntax: ASSIGN <name> <site>
    effect: Associates the user chosen string <name> with a
            connection to the ARPANET site <site>.

TALK:

    syntax: TALK <name>
    effect: Switches from command mode to remote mode
            directing subsequent console input to the site
            associated with <name>. If no ARPANET site is
            currently associated with <name>, the user is
            asked to spesify a site. The first time the
            user "talks" to a particular named site MLTNET
            goes through the ARPANET initial connection
            protocol with the remote site in order to
            establish a duplex connection with it.

NAMES:

    syntax: NAMES
    effect: Prints on the console the <name>/<site>
            associatins currently known to MLTNET.

QUIT:

    syntax: QUIT
    effect: Returns control to the TENEX EXEC breaking all
            connections with remote hosts. It is good
            practice to log out of each remote host before
            using the QUIT command.

NETSTAT:

    syntax: NETSTAT
    effect: Prints on the console the network status as seen
            from the local TENEX.

RENAME:

    syntax: RENAME <name>1 <name>2
    effect: Associates <name>2 with the ARPANET site
            previously associated with <name>1.

FLUSH:

    syntax: FLUSH <name>
    effect: Breaks the network connection with the ARPANET
            site associated with <name> and, in addition,
            breaks the association between <name> and that
            site.

HOSTS:

    syntax: HOSTS
    effect: Prints on the console the list of hosts
            currently known to the MLTNET subsystem.

HELP:

    syntax: HELP

    effect: Prints on the console a breif summary of how to
            use MLTNET.

Remote Mode Commands

In remote mode MLTNET recognizes the escape character "!" as a signal to interpret the following character as a command. Currently MLTNET recognizes the following characters as commands to it:

Q: (quit) Causes MLTNET to switch from remote mode to local

    mode.

L: (local echo) Causes MLTNET to echo characters as it

    transmits them to the remote site. ;L is the inverse of
    R. The default case.

R: (remote echo) Causes MLTNET to transmit characters typed

    to it without echoing them; invers of L.

U: (upper case) Causes MLTNET to transmit upper case letters

    as typed; the inverse of S. The default case.

S: (small letters - lower case): Causes MLTNET to transmit

    upper case letters typed to it as lower case letters.
    In this mode of operation "^" acts as a shift key; "^"
    may be transmitted by typing "!^". S is the inverse of
    U.

X: (where X is any character other than Q, L, R, U or S):

    Causes MLTNET to transmit X.

The following is an annotated scenario which illustrates the use of MLTNET; in it characters typed by the users are underlined.

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    [ into the online RFC archives by Tor Fredrik Aas 1/98 ]