Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!decvax!ucbvax!HUEY.UDEL.EDU!mills From: mills@HUEY.UDEL.EDU.UUCP Newsgroups: mod.protocols.tcp-ip Subject: Re: TCP RTT woes revisited Message-ID: <8612160436.AA18179@ucbvax.Berkeley.EDU> Date: Mon, 15-Dec-86 18:07:57 EST Article-I.D.: ucbvax.8612160436.AA18179 Posted: Mon Dec 15 18:07:57 1986 Date-Received: Wed, 17-Dec-86 03:51:43 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 14 Approved: tcp-ip@sri-nic.arpa Craig and Bob, Keeping roundtrip-delay samples on a per-packet basis really does help (the fuzzballs have been doing that for several years), as does initializing the estimator with the SYN/ACK exchange. Another thing, first pointed out by Jack Haverty of BBN, is the behavior when the window first opens after it has previously closed. If the ACK carrying the window update is lost, performance can lose big. This may be one reason TP-4 uses a different "active ACK" policy. While at it, consider the receiver policy and when to generate ACKs (delayed or not). Silly implementations that always send 2-3 ACKs for every received packet might actually win under warmonger conditions. Dave