Path: utzoo!attcan!uunet!husc6!mailrus!ames!pasteur!ucbvax!rusvx1.rus.uni-stuttgart.dbp.de!nittmann From: nittmann@rusvx1.rus.uni-stuttgart.dbp.de ("Michael F.H. Nittmann ") Newsgroups: comp.protocols.tcp-ip Subject: historical defaults Message-ID: <111:nittmann@rusvx1.rus.uni-stuttgart.dbp.de> Date: 27 Jun 88 13:13:10 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 47 Throwing in the following I would like to see if it is worth being discussed: there are two defaults in the telnet standard that are a little bit hampering on networks since on my opinion they cause lots of evitable network charge: go ahead and remote echo. On my own experience most communications in interactive telnet use are from a workstation to a mainframe computer. The lines are full duplex as seen from the telnet side. A virtual circuit of two phone lines or a x.25 virtual circuit look as a full duplex line to the telnet. So: why bother with a go ahead as a default start and not just set SGA as a default. The same I think holds for the remote echo. This is a very useful option when operating over very unreliable lines to very unreliable hosts. When communicating over a standard network which is reliable as seen from the bottom side of telnet, and when the tcp/ip used as a type 4 protocol would take care of resending characters if they are lost or timed out, so why charge the already overcrowded network ( re. the breakdowns early in '88) with those single character echo packets. I would guess that nowadays - in 88, not in times on NCP-->TCP transition - most communications could easily be done with SGA and local echo. Seen from the mainframe pespective I personnally judge it a gigantesque waste of resources to let a multi user mainframe echo single characters - mainframes may of course switch that off by negotiating, as is done with SGA. The problem I see in my experience is that some implementations heavily rely on the defaults. When confronted with a non default negotiation at communication start some implementations don't work correctly. They either insist negotiating their default or just hang waiting for a GA. By switching the defaults - SGA and local echo - I think we could avoid network charge - two defaults together never would negotiate e.g. the echo since there is no reson so they will send those silly 1 character packets. On the other hand implementors would perhaps be oriented to the more useful modes as is SGA. Or is there somebody who really knows he needs the GA any more? Perhaps this will result in a level 3 or level 4 discussion opposed to the link level discussion on connectors.(this is OSI terminology). And as usual: these are my personal views. Michael F.H.Nittmann