From owner-freebsd-net Wed Apr 10 11:10:30 2002 Delivered-To: freebsd-net@freebsd.org Received: from hairball.treehouse.napa.ca.us (dsl-64-128-194-169.telocity.com [64.128.194.169]) by hub.freebsd.org (Postfix) with ESMTP id 000BF37B400 for ; Wed, 10 Apr 2002 11:10:27 -0700 (PDT) Received: (from mailnull@localhost) by hairball.treehouse.napa.ca.us (8.11.6/8.11.6) id g3AIARO48271 for freebsd-net@freebsd.org; Wed, 10 Apr 2002 11:10:27 -0700 (PDT) (envelope-from mailnull) Received: (from news@localhost) by hairball.treehouse.napa.ca.us (8.11.6/8.11.6) id g3AIAM248257 for treehouse-mail-freebsd-net@hairball.treehouse.napa.ca.us; Wed, 10 Apr 2002 11:10:22 -0700 (PDT) (envelope-from news) From: "G. Paul Ziemba" To: treehouse-mail-freebsd-net@treehouse.napa.ca.us Subject: Re: TCP Timestamp option? Date: Wed, 10 Apr 2002 18:10:22 +0000 (UTC) Message-id: Reply-To: paul+usenet@w6yx.stanford.edu Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org ipver4@hotmail.com ("ipver four") writes: >Is there a reason for including the timestamp option on most of the TCP >packets? The TCP timestamp option is used to obtain better round-trip time estimates than can be obtained without, and these estimates turn out to be important in networks with large bandwidth*delay products. Timestamps in the timestamp option also cycle much more slowly than sequence numbers on an active high-speed connection and can thus be used to detect and discard old duplicate packets with apparently valid sequence numbers. RFC 1323 explains the details. -- G. Paul Ziemba paul@w6yx.stanford.edu FreeBSD unix: 11:06AM up 16 days, 14 mins, 7 users, load averages: 0.03, 0.03, 0.00 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message