Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: utzoo!watmath!clyde!cbosgd!ihnp4!ucbvax!cisl-service-multics.arpa!Mills From: Mills@CISL-SERVICE-MULTICS.ARPA Newsgroups: mod.protocols.tcp-ip Subject: Zero window probes Message-ID: <851108205728.000456@CISL-SERVICE-MULTICS.ARPA> Date: Fri, 8-Nov-85 15:57:00 EST Article-I.D.: CISL-SER.851108205728.000456 Posted: Fri Nov 8 15:57:00 1985 Date-Received: Tue, 12-Nov-85 04:31:41 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 17 Approved: tcp-ip@ucbvax.berkeley.edu I am wondering what the appropriate action for a TCP connection that is sending out zero window probes and recieveing ACKS for the last octet of the window. For a small amount of time you obviously want to keep the connection around in case the window opens. The real question comes in when the window has been closed for some time. One argument is, that if you are recieving valid ACKS the other end is alive so keep the connection open. The other is that if has been that long since you were able to transmit something is probably wrong with the connection. In looking in RFC-793 this issue seems to be rather glossed over. I am using the September '81 version of the RFC form the protocol transition workbook. Is this the up-to-date spec? Any information or pointers into the specs would be very helpful. Thanks, John Mills