Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!swrinde!ucsd!ucbvax!FTP.COM!jbvb From: jbvb@FTP.COM (James B. Van Bokkelen) Newsgroups: comp.protocols.tcp-ip Subject: Re: Reliable Datagram ??? Protocols Message-ID: <9010311611.AA29259@ftp.com> Date: 31 Oct 90 16:11:59 GMT Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: jbvb@ftp.com Organization: The Internet Lines: 21 From: Charles Lynn Doesn't TCP require the connection to be in the ESTABLISHED state before it is permitted to deliver data to the application? If so, I think B cannot see the data until it gets the ACK of its SYN from A, thus the response from B cannot be includes with B's SYN ACK. You're right: RECEIVE calls are supposed to be queued until the connection reaches ESTABLISHED (RFC 793, pg 58). The discussion of OPEN, SEND and RECEIVE in that section seems somewhat out of line with the requirement elsewhere in the RFC that TCPs accept data with the initial SYN, because it appears that the API specified in section 3.9 can't generate it (SENDs are queued until the connection reaches ESTABLISHED as well). I will raise this as an issue with the HR WG. My own initial feeling is that the API's restriction is unnecessary, and could be relaxed at considerable benefit to the Internet... James B. VanBokkelen 26 Princess St., Wakefield, MA 01880 FTP Software Inc. voice: (617) 246-0900 fax: (617) 246-0901