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 Message-ID: <19970920185623.YM44251@uriah.heep.sax.de> In-Reply-To: <Pine.BSF.3.91.970920100834.15878B-100000@bmccane.uit.net>; from Wm Brian McCane on Sep 20, 1997 10:10:58 -0500 References: <199709191037.KAA03250@mofo.frt.dec.com> <Pine.BSF.3.91.970920100834.15878B-100000@bmccane.uit.net>
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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. ;-)
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