RFC 513 (rfc513) - Page 2 of 3
Comments on the new Telnet specifications
Alternative Format: Original Text Document
RFC 513 COMMENTS ON THE NEW TELNET SPECIFICATIONS May 1973 most TELNET commands) but they then include "and perhaps other characters or character strings as well". To eliminate the difficulty of implementing an undefined set of "interesting" things, I would propose that the set of "interesting" things, contain only the DM command itself. The TELNET "synch" would thus be defined as "discard all input up to and including the next DM command." This change should cause no problems with user-generated "interesting" things if they are sent after the "synch" (as specified in the proposed new File Transfer Protocol Specifications). System-generated signals (such as option requests) could be discarded, however, so some additional discussion is in order. If the recommendation that requests not be sent except when something changes is followed, the spontaneous generation of "interesting" things by TELNET itself (whatever that implies) would seem to be rare, especially at the same time that users are generating "synch's". A more positive solution could be had by defining a "synch response" (SR) TELNET command. The SR command would be sent when the INS and DM had both been processed (ie, when the "synch" had been completely received). If a process should ever receive an SR when it has an option request outstanding, the request has been discarded and must be repeated. User processes which carry on option negotiations would be the generators of any "synch's" so they can handle discarded option requests as desired. Note that this assumes that the TELNET process itself will never generate a spontaneous "synch"; comments are solicited on this. Another possible solution would be to define a "TIMING-MARK" TELNET command (see "TELNET Timing Mark Option", NIC # 16238), which would be sent immediately following the DM of a "synch". The response to the TIMING-MARK (also to be defined) would mean the same as the proposed SR command. The final non-editorial comment concerns the need for some means of specifying horizontal tab positions and use. This is quite a nuisance when dealing with systems which normally handle tabs for local terminals. Perhaps this issue can be best handled with an appropriate option; comments are solicited. The only editorial comments are on the TELNET Protocol document, which I reference below by page number. On page 8 the parenthetical comment "(i.e., when a process at one end of a TELNET connection is 'blocked on input')" should either be removed or rewritten to avoid the (to me) incomprehensible phrase "blocked on input." If additional discussion is felt to be necessary, I would propose "i.e., when a process at one end of a TELNET connection cannot proceed without additional input)." If examples are felt necessary, I would propose "(e.g., in the state characterized by the Multics term 'blocked on input')." The parallel could also be drawn between the GA and the concept of a "read command" being issued to request more input. Hathaway
