From owner-freebsd-hackers Wed Sep 11 14:45:32 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id OAA04070 for hackers-outgoing; Wed, 11 Sep 1996 14:45:32 -0700 (PDT) Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id OAA04053; Wed, 11 Sep 1996 14:45:27 -0700 (PDT) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id XAA08985; Wed, 11 Sep 1996 23:17:07 +0200 From: Luigi Rizzo Message-Id: <199609112117.XAA08985@labinfo.iet.unipi.it> Subject: Changing default TCP window size ? To: hackers@freebsd.org Date: Wed, 11 Sep 1996 23:17:07 +0200 (MET DST) Cc: wollman@lcs.mit.edu, phk@freebsd.org X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk How do I force TCP (or the OS) to use a window size different from the default 16K ? The following code mywin=DESIRED_WINDOW_SIZE; setsockopt(f, SOL_SOCKET, SO_SNDBUF, (char *)&mywin, sizeof mywin) appears to set the value correctly (it can be read back with getsockopt) but then it appears not to have any effect on TCP (monitoring the connection with netstat -na always shows a Send-Q around 16KB, and the throughput in window-limited configurations remains unchanged). I have also tried to alter net.inet.tcp.sendspace but with no effect. I am asking because I would really like to try out large windows and check if RFC1323 extensions really work (I have been told there are some unspecified problems). Thanks Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 http://www.iet.unipi.it/~luigi/ ====================================================================