From owner-freebsd-net Fri Apr 13 8:22:31 2001 Delivered-To: freebsd-net@freebsd.org Received: from sj-msg-core-4.cisco.com (sj-msg-core-4.cisco.com [171.71.163.10]) by hub.freebsd.org (Postfix) with ESMTP id D01AD37B446; Fri, 13 Apr 2001 08:22:21 -0700 (PDT) (envelope-from bmah@cisco.com) Received: from bmah-freebsd-0.cisco.com (bmah-freebsd-0.cisco.com [171.70.84.42]) by sj-msg-core-4.cisco.com (8.9.3/8.9.1) with ESMTP id IAA19064; Fri, 13 Apr 2001 08:22:18 -0700 (PDT) Received: (from bmah@localhost) by bmah-freebsd-0.cisco.com (8.11.3/8.11.1) id f3DFMDB24703; Fri, 13 Apr 2001 08:22:13 -0700 (PDT) (envelope-from bmah) Message-Id: <200104131522.f3DFMDB24703@bmah-freebsd-0.cisco.com> X-Mailer: exmh version 2.3.1 01/19/2001 with nmh-1.0.4 To: Julian Elischer Cc: Toni SOUEID , freebsd-bugs@FreeBSD.ORG, freebsd-net@FreeBSD.ORG Subject: Re: Problem in TCP initialisation of cwnd In-Reply-To: <3AD711EE.EEADD293@elischer.org> References: <000901c0c422$bd356860$941f7ec2@hamster> <3AD711EE.EEADD293@elischer.org> Comments: In-reply-to Julian Elischer message dated "Fri, 13 Apr 2001 07:49:18 -0700." From: bmah@cisco.com (Bruce A. Mah) Reply-To: bmah@cisco.com X-Face: g~c`.{#4q0"(V*b#g[i~rXgm*w;:nMfz%_RZLma)UgGN&=j`5vXoU^@n5v4:OO)c["!w)nD/!!~e4Sj7LiT'6*wZ83454H""lb{CC%T37O!!'S$S&D}sem7I[A 2V%N&+ X-Image-Url: http://www.employees.org/~bmah/Images/bmah-cisco-small.gif X-Url: http://www.employees.org/~bmah/ Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_423415747P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Fri, 13 Apr 2001 08:22:13 -0700 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org --==_Exmh_423415747P Content-Type: text/plain; charset=us-ascii If memory serves me right, Julian Elischer wrote: > > One thing that shocked me is that a TCP connection in FreeBSD (at least on > > my machines) > > doesn't begin with a slow start but rather sends a huge amount of packets t > o > > the other end > > (this huge amount only seems to be limited either by the receiver window or > > by the local machine's > > send buffer). It seems that cwnd isn't initialised. > > It is my understanding that it does this only if the destination is considere > d > 'local' > (i.e in the same subnet.) This is my recollection too, but I can't off-hand recall the reference for this (other than looking in the source code). I'm betting that these sysctl variables let one tweak this behavior: net.inet.tcp.slowstart_flightsize: 1 net.inet.tcp.local_slowstart_flightsize: 65535 Bruce. --==_Exmh_423415747P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.4 (FreeBSD) Comment: Exmh version 2.2 06/23/2000 iD8DBQE61xml2MoxcVugUsMRAqTlAKCT0/EfzRehcO13iQJ31nZF9mXIdQCgjl2B uLSjGAmZYYPXBPZjqHS/XdE= =YW0/ -----END PGP SIGNATURE----- --==_Exmh_423415747P-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message