GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc656

TELNET OUTPUT VERTICAL TABSTOPS OPTION RFC 656, NIC 31159 (Oct. 25, 1974)" D. Crocker (UCLA-NMC) Online file: [ISI]<DCROCKER>NAOVTS.TXT

              TELNET OUTPUT VERTICAL TABSTOPS OPTION

1. Command name and code

 NAOVTS 14
    (Negotiate About Vertcial Tabstops)

2. Command meanings

 In the following, we are discussing a simplex connection, as described in 
 the NAOL and NAOP Telnet Options specifications.
    IAC DO NAOVTS 
       The data sender requests or agrees to negotiate about output
       vertical tabstops with the data receiver.  In the case where
       agreement has been reached and in the absence of further
       subnegotiations, the data receiver is assumed to be handling output
       vertical tabstop considerations.
    IAC DON'T NAOVTS 
       The data sender refuses to negotiate about output vertical tabstops 
       with the data receiver, or demands a return to the unnegotiated 
       default mode.
    IAC WILL NAOVTS 
       The data receiver requests or agrees to negotiate about output 
       vertical tabstops with the sender.  In the case where agreement has 
       been reached and in the absence of further subnegotiations, the data 
       receiver alone is assumed to be handling output vertical tabstop 
       considerations.
    IAC WON'T NAOVTS 
       The data receiver refuses to negotiate about output vertical
       tabstops, or demands a return to the unnegotiated default mode.
    IAC SB NAOVTS DS <8-bit value> ... <8-bit value> IAC SE
       The data sender specifies, with the 8-bit value(s), which party
       should handle output vertical tabstop considerations and what the
       stops should be.  The code for DS is 1.
    IAC SB NAOVTS DR <8-bit value> ... <8-bit value> IAC SE
       The data receiver specifies, with the 8-bit value(s), which party 
       should handle output vertical tabstop considerations and what the 
       stops should be.  The code for DR is 0.

3. Default

 DON'T NAOVTS/WON'T NAOVTS.
    In the default absence of negotiations concerning which party, data
    sender or data receiver, is handling output vertical tabstop
    considerations, neither party is required to handle vertical tabstops
    and neither party is prohibited from handling them; but it is
    appropriate if at least the data receiver handles vertical tabstop
    considerations, albeit primitively.

4. Motivation for the Option

 Please refer to section 4 of the NAOL and of the NAOVTS Telnet option 
 descriptions.

5. Description of the Option

 The data sender and the data receiver use the 8-bit value(s) along with
 the DS and DR SB commands as follows (multiple 8-bit values are allowed
 only if each is greater than zero and less than 251):
    8-bit value                      Meaning                      
    0            Command sender suggests that he alone will handle  
                 the vertical tabstops, for the connection.         
    1 to 250     Command sender suggests that the other party alone 
                 should handle the stops, but suggests that the     
                 indicated value(s) be used.  Each value is the line 
                 number, relative to the top of the printer page or 
                 terminal screen, that is to be set as a vertical   
                 tabstop.                                           
    251 to 254   Not allowed, in order to be compatible with        
                 related Telnet options.                            
    255          Command sender suggests that the other party alone 
                 should handle output vertical tabstops and         
                 suggests nothing about how it should be done.      
 The guiding rules are that:
    1) if neither data receiver nor data sender wants to handle output 
    vertical tabstops, the data receiver must do it, and
    2) if both data receiver and data sender want to handle output vertical 
    tabstops, the data sender gets to do it.

The reasoning for the former rule is that if neither wants to do it, then the default in the NAOVTS option dominates. If both want to do it, the sender, who is presumed to have special knowledge about the data, should be allowed to do it, taking into account any suggestions the receiver may make. This is necessary due to the assynchrony of network transmissions. As with all option negotiations, neither party should suggest a state already in effect except to refuse to negotiate; changes should be acknowledged; and once refused, an option should not be resuggested until "something changes" (e.g., another process starts). At any time, either party can disable further negotiation by giving the appropriate WON'T NAOVTS or DON'T NAOVTS command.

/home/gen.uk/domains/wiki.gen.uk/public_html/data/pages/rfc/rfc656.txt · Last modified: 1992/10/15 21:52 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki