Date: Mon, 22 Sep 1997 17:27:49 -0500 (CDT) From: Wm Brian McCane <root@bmccane.uit.net> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de> Cc: hackers@FreeBSD.ORG Subject: Re: ISDN Modems Message-ID: <Pine.BSF.3.91.970922172249.8910A-100000@bmccane.uit.net> In-Reply-To: <19970920185623.YM44251@uriah.heep.sax.de>
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On Sat, 20 Sep 1997, J Wunsch wrote: > 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. ;-) > I intentionally compared apples to oranges. I don't transfer very many compressed binary files, but I do transfer a LOT of UseNet news and e-mail. (Not the binary groups, so don't put uuencode in the conversation). I am targetting MY needs. I have decided on the Pipeline 50's partially because their documentation says that they will compress data received on the 10BaseT port at rates "up to" 512K/second 8-P. (Yeah, like I'll believe that when I see it 8). I have looked at the iijppp, and the "new" ppp changes to support BSD Comp in Kernel, it looks nice, but my ISP uses LPM3's and Windows NT, so I don't think it will help. brian +-------------------------------------+----------------------------------------+ He rides a cycle of mighty days, and \ Wm Brian and Lori McCane he represents the last great schizm \ McCane Consulting among the gods. Evil though he obviously \ root@bmccane.uit.net is, he is a mighty figure, this father of \ http://bmccane.uit.net/ my spirit, and I respect him as the sons \ http://bmccane.uit.net/~pictures/ of old did the fathers of their bodies. \ http://bmccane.uit.net/~bmccane/ Roger Zelazny - "Lord of Light" \ http://bmccane.uit.net/~bbs/ +---------------------------------------------+--------------------------------+
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