From owner-freebsd-hackers Sat Sep 20 10:15:49 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id KAA16311 for hackers-outgoing; Sat, 20 Sep 1997 10:15:49 -0700 (PDT) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by hub.freebsd.org (8.8.7/8.8.7) with SMTP id KAA16303 for ; Sat, 20 Sep 1997 10:15:40 -0700 (PDT) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id TAA15362 for hackers@FreeBSD.ORG; Sat, 20 Sep 1997 19:15:37 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.8.7/8.8.5) id SAA04270; Sat, 20 Sep 1997 18:56:23 +0200 (MET DST) Message-ID: <19970920185623.YM44251@uriah.heep.sax.de> Date: Sat, 20 Sep 1997 18:56:23 +0200 From: j@uriah.heep.sax.de (J Wunsch) To: hackers@FreeBSD.ORG Subject: Re: ISDN Modems References: <199709191037.KAA03250@mofo.frt.dec.com> X-Mailer: Mutt 0.60_p2-3,5,8-9 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: ; from Wm Brian McCane on Sep 20, 1997 10:10:58 -0500 Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk As Wm Brian McCane wrote: > Only 7.5kB/sec? I am now very confused. I get 6kB/s throughput > from my 33.6 most of the time. Of course I am usually transferring > news/mail so they are highly compressible. Do any of the plug-in > cards do LZ compression, or anything similar? You are comparing apples and oranges. A 33.6 kbps modem can at best transfer 4.2 KB/s raw data (a little less due to the required protocol overhead). The remainder is done by on-the-fly compression. Use the data rate when getting a .tar.gz file as a base for your comparisions. ISDN itself doesn't provide for on-the-fly compression, so the raw data rate is close to 8 KB/s. The 7.5 KB/s is the common data rate for IP traffic. PPP provides for potential link-level compression. One of the options is ``BSD compression'' which should be close to the typical modem compression ratios. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)