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From: rhh@ct.picker.com (Randall Hopper)
Message-Id: <199608020040.UAA09666@elmer.picker.com>
Subject: Re: PPP vs. PLIP
To: norton@nrlmry.navy.mil
Date: Thu, 1 Aug 1996 20:40:14 -0400 (EDT)
Cc: hackers@freebsd.org
In-Reply-To: <199608011902.MAA05218@norton.nrlmry.navy.mil> from "norton@nrlmry.navy.mil" at Aug 1, 96 12:02:58 pm
Reply-To: rhh@ct.picker.com
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norton@nrlmry.navy.mil:
 >I just picked up a microcom modem for connecting to my ISP (they hook
 >into a T1).  They are running microcom modems also.  This is a 28.8
 >modem.
 >
 >The modem info says that you can hook it up to either a serial port or
 >a parallel port - and claims that the parallel port arrangement will
 >give you about 3x the throughput.
 >
 >I was wondering if anyone had any feedback as to if you would really
 >see higher bandwidth running through the parallel port (using PLIP, I
...
 >terms of both speed and reliability?  From what I can tell, I get
 >about 18kbits/sec on things like ftp's currently.

If you've got a fast serial port (16550 -- 16 byte FIFO), that's plenty
fast enough to handle 28.8K dial-up connection even with full data
compression on (56K-60K or so for highly compressible content).  Also to my
knowledge, FreeBSD supports FIFOs on fast serial ports, but doesn't support
the advanced features of ECP/EPP parallel ports.  So I think you'd have
less system overhead with SLIP or PPP over a fast serial port (though at
dial-up speeds I really don't know whether it'd make a noticable
difference).

Randall Hopper
rhh@ct.picker.com