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From: j@bonnie.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Asynch throughput [Was: Re: connecting a sparc10 and PC together]
Date: 21 Jun 1995 10:28:22 +0200
Organization: Private U**x site, Dresden.
Lines: 22
Message-ID: <3s8l76$li2@bonnie.tcd-dresden.de>
References: <9506091435.AA28260@akela.src.honeywell.com> <Pine.SOL.3.91.950618164651.1054C-100000@knobel.gun.de>
Reply-To: joerg_wunsch@uriah.heep.sax.de
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Andreas Klemm <andreas@knobel.gun.de> wrote:
>> 3) PPP connection: I run a null modem cable between the Sun and PC, and
>> run PPP between them. Question: what kind of throughput can be expected?
>
>Sun's serial devices are only capable of 38400 Baud. Figure out yourself,
>what performance you might get. Perhaps 4k/sec. With a 19200 Baud Modem
>(Zyxel) I get about 2.1K/sec. ...
Less than 4 KB/s. This is an asynch protocol, so you've got 10 bits
per byte. Makes 3.8 KB/s grand total, minus the IP and TCP overhead.
Your ZyXEL gets more than 1.9 KB/s since it's running a higher DTE
speed and uses on-line compression (and, if i remember well, the
protocol on the phone line is a synchronous one, so the overhead is
smaller). Of course, with PPP on-line compression, the throughput
might also be higher, but this heavily depends on the kind of data.
--
cheers, J"org private: joerg_wunsch@uriah.heep.sax.de
http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)