RFC885 - Telnet end of record option

Network Working Group J. Postel

Request for Comments: 885 ISI

December 1983

TELNET END OF RECORD OPTION

This RFCspecifies a standard for the ARPA Internet community. Hosts on

the ARPA Internet that need to mark record boundaries within Telnet

protocol data are eXPected to adopt and implement this standard.

1. Command Name and Code

END-OF-RECORD 25

2. Command Meanings

IAC WILL END-OF-RECORD

The sender of this command requests permission to begin

transmission of the Telnet END-OF-RECORD (EOR) code when

transmitting data characters, or the sender of this command

confirms it will now begin transmission of EORs with transmitted

data characters.

IAC WON'T END-OF-RECORD

The sender of this command demands to stop transmitting, or to

refuses to begin transmitting, the EOR code when transmitting data

characters.

IAC DO END-OF-RECORD

The sender of this command requests that the sender of data start

transmitting the EOR code when transmitting data, or the sender of

this command confirms that the sender of data is expected to

transmit EORs.

IAC DON'T END-OF-RECORD

The sender of this command demands that the receiver of the

command stop or not start transmitting EORs when transmitting

data.

3. Default

WON'T END-OF-RECORD

DON'T END-OF-RECORD

END-OF-RECORD is not transmitted.

RFC885 December 1983

4. Motivation for the Option

Many interactive systems use one (or more) of the normal data

characters to indicate the end of an effective unit of data (i.e., a

record), for example, carriage-return (or line-feed, or escape).

Some systems, however, have some special means of indicating the end

of an effective data unit, for example, a special key. This Telnet

option provides a means of communicating the end of data unit in a

standard way.

5. Description of the Option

When the END-OF-RECORD option is in effect on the connection between

a sender of data and the receiver of the data, the sender transmits

EORs.

It seems probable that the parties to the Telnet connection will

transmit EORs in both directions of the Telnet connection if EORs are

used at all; however, the use of EORs must be negotiated

independently for each direction.

When the END-OF-RECORD option is not in effect, the IAC EOR command

should be treated as a NOP if received, although IAC EOR should not

normally be sent in this mode.

6. Implementation Considerations

As the EOR code indicates the end of an effective data unit, Telnet

should attempt to send the data up to and including the EOR code

together to promote communication efficiency.

The end of record is indicated by the IAC EOR 2-octet sequence. The

code for EOR is 239 (decimal).