Telnet end of record option

　　Network Working Group J. Postel

　　Request for Comments: 885 ISI

　　December 1983

　　TELNETEND 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.

　　RFC885December 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).