Subject: Re: Multiple net interfaces
To: Robert Shady <>
From: Greg S. Burd <>
List: current-users
Date: 03/01/1994 17:36:03
Robert Shady Writes:
	Right.  So does the Livingston Portmaster Terminal Server, but I
	don't have one of those, hence the question.  Somehow, there must
	be a way to connect two SLIP/PPP devices to a dial-up SLIP/PPP
	provider and have 2*(modem speed) throughput (or more!).

This is impossible for several reasons.  First, the nature of IP routing.   
Second, the speed at which your system can operate.  SLIP and PPP generate a  
huge amount of over head even with a really good serial card.  Unless you get  
a serial card which does DMA, VESA, or PCI data transfers, the processing  
overhead will saturate your 486-DX4 or even your Pentium.  38400 BPS is lot  
of information to move across an 8, 16, or even 32 bit bus with all the  
interrupts, etc.  Even if the serial driver is "smart" enough to do larger  
transfers, the overhead is a problem.  This is why MorningStar Technologies  
has something called SnapLink(tm).  It is a SCSI serial device designed to  
handle T1 bandwidth.


- greg

Greg Burd
Marble Associates, Inc.

#include <std/disclaimer.h>