RFC 946 (rfc946) - Page 1 of 4
Telnet terminal location number option
Alternative Format: Original Text Document
Network Working Group R. Nedved
Request for Comments: 946 Carnegie-Mellon University
May 1985
TELNET TERMINAL LOCATION NUMBER OPTION
Status of this Memo
This RFC proposes a new option for Telnet for the ARPA-Internet
community, and requests discussion and suggestions for improvements.
Distribution of this memo is unlimited.
Overview
In a community of users that share a large degree of common
facilities, it is often advantageous to use some common feature to
improve software performance and reduce initial implementation costs.
In March of 1982, CMU designed and implemented based on the growing
CMU PUP-based network a terminal location database and modified
existing network software to handle a 64-bit number which some call
the Terminal Location Number or TTYLOC for short. The number can be
efficiently stored in operating systems tables and can be passed
between various levels of operating system and network layering with
minimum modifications to existing software. An initial evaluation of
changing software to communicate an unfixed or reasonable length
terminal location string indicated it would be expensive.
CMU now wishes to extend this mechanism into the TCP-based networking
support that is replacing the existing PUP-based software. The
mechanism is not viewed as a replacement for the Telnet Terminal
Location (SEND-LOCATION) Option but as a shorthand mechansim for
communicating hosts in the same community.
TTYLOC Number
The TTYLOC number is a 64-bit number composed of two (2) 32-bit
numbers: The 32-bit official ARPA Internet host address (may be any
one of the addresses for multi-homed hosts) and a 32-bit number
representing the terminal on the specified host. The host address of
[0.0.0.0] is defined to be "unknown", the terminal number of FFFFFFFF
(hex, r or-1 in decimal) is defined to be "unknown" and the terminal
number of FFFFFFFE (hex, or -2 in decimal) is defined to be
"detached" for processes that are not attached to a terminal.
Nedved