From owner-freebsd-net Thu Sep 17 00:00:28 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id AAA05536 for freebsd-net-outgoing; Thu, 17 Sep 1998 00:00:28 -0700 (PDT) (envelope-from owner-freebsd-net@FreeBSD.ORG) Received: from chappe.cnes.fr (chappe.cnes.fr [132.149.22.2]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id AAA05516; Thu, 17 Sep 1998 00:00:25 -0700 (PDT) (envelope-from kevin.choi@cnes.fr) Received: from pasteur.cst.cnes.fr (pasteur.cnes.fr [132.149.22.8]) by chappe.cnes.fr (8.9.1a/8.9.1a/980831) with ESMTP id IAA27749; Thu, 17 Sep 1998 08:59:50 +0200 (MET DST) Received: from imhotep.cst.cnes.fr (unverified) by pasteur.cst.cnes.fr (Content Technologies SMTPRS 2.0.15) with SMTP id ; Thu, 17 Sep 1998 09:00:38 +0200 Received: from pc-kichoi (pc-kichoi.cst.cnes.fr [132.149.9.82]) by imhotep.cst.cnes.fr (8.6.12/MH-19960223.01) with SMTP id JAA27151; Thu, 17 Sep 1998 09:00:35 +0200 From: "Kevin Kyeong-il CHOI" To: "FreeBSD Question" , "FreeBSD Net" , Subject: Why FreeBSD (or Solaris as well) get stuck in case of long delay ? Date: Thu, 17 Sep 1998 08:59:32 +0200 Message-Id: <006801bde208$b8e51ac0$52099584@pc-kichoi.cst.cnes.fr> MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook 8.5, Build 4.71.2232.26 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 Content-Type: multipart/mixed; boundary="----=_NextPart_000_0069_01BDE219.7C6DEAC0" Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org This is a multi-part message in MIME format. ------=_NextPart_000_0069_01BDE219.7C6DEAC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hi, I'd like to have some expertized opinions. I have a ATM network (25 Mbps) as follows; [FreeBSD Box]---+---[Delay generator]---+---[SUN Solaris] | | [Windows 98]----+ +---[Windows NT] | | [Windows NT]----+ +---[FreeBSD 2] The delay generator can introduce the packet delays upto couple of seconds for TCP or UDP packets. When there is no delay, the whole link between left and right side shows the maximum performance which is about 20 Mbps. BUT, once the delay is introduced, the famous rule Capacity = RTT x Bandwidth. and the capacity would be limited by the window size. Here, I used 64K for Window size (65536), so the Bandwidth should be Bandwidth = Capacity (65536) / RTT I made the delay in one way as 200 ms, and RTT becomes 400 ms, so the nominal Bandwidth becomes 1310720 bps = 1.3 Mbps. Curiously enough, between two Windows boxes, the maximum bandwidth is obtained, which is about 1.0 ~ 1.1 Mbps. BUT, for FreeBSD, or for Solaris, I obtain only 200 ~ 300 kbps. (precisely 200 kbps for Solaris, and 300 kbps for FreeBSD). I don't understand what happened, but guess that the UNIX machines may evaluate the RTT in a wrong way or what ... Can anyone have a similar experience, please give me an e-mail. ------------------------------------- Kevin Kyeong-il CHOI ~'/ (o\) ^ \___/o Doctoral Research Engineer Service DEE/IR/TSI/TN Centre National d'Etudes Spatiales 18 Avenue Edouard-Belin 31401 Toulouse cedex 4 France (Tel) +33-561 28 15 31 (Fax) +33-561 28 29 13 (Email) kevin.choi@cnes.fr (www) http://www.chez.com/kichoi/ ------------------------------------- ------=_NextPart_000_0069_01BDE219.7C6DEAC0 Content-Type: application/octet-stream; name="Kevin Kyeong-il CHOI.vcf" Content-Disposition: attachment; filename="Kevin Kyeong-il CHOI.vcf" Content-Transfer-Encoding: 7bit BEGIN:VCARD VERSION:2.1 N:CHOI;Kevin;Kyeong-il;; FN:Kevin Kyeong-il CHOI ORG:CNES; TITLE:Dr TEL;WORK;VOICE:(05) 61 28 15 31 TEL;HOME;VOICE:(05) 62 17 01 99 EMAIL;PREF;INTERNET:kevin.choi@cnes.fr REV:19980710T091856Z END:VCARD ------=_NextPart_000_0069_01BDE219.7C6DEAC0-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message