Date: Thu, 17 Sep 1998 13:42:31 -0500 (CDT) From: Kris Kirby <kkirby@pluto.cs.uah.edu> To: freebsd-questions@FreeBSD.ORG Cc: Kevin Kyeong-il CHOI <kevin.choi@cnes.fr>, FreeBSD Net <freebsd-net@FreeBSD.ORG> Subject: Re: Why FreeBSD (or Solaris as well) get stuck in case of long delay ? Message-ID: <Pine.GSO.3.95.980917133634.24130A-100000@pluto> In-Reply-To: <199809171437.HAA06002@implode.root.com>
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> > 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). > > FreeBSD is almost certainly still using a window of 16KB. There are > problems in the code related to changing the socket buffer size after the > system is up. You pretty much have to modify the default value in the > kernel source files in order to use a larger window. > > -DG > I think it is worth noting that 200Kbytes/s is equal to 1.6 Mbit/s. And thus, 300Kbytes/s is equal to 2.4 Mbit/s. Does that even it out? Kris Kirby UAH Mail <kirbyk@email.uah.edu> CS <kkirby@cs.uah.edu> Home <kris@airnet.net> WWW <nomurphy@hotmail.com> ------------------------------------------- TGIFreeBSD... 'Nuff said. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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