Subject: Re: rdist vs. sup
To: Don Lewis <firstname.lastname@example.org>
From: Greg A. Woods <email@example.com>
Date: 03/03/1995 14:08:17
[ On Fri, March 3, 1995 at 07:38:18 (-0800), Don Lewis wrote: ]
> Subject: Re: rdist vs. sup
> Over a serial link using error correcting modems (V.42, etc.) I'd say
> the most likely packet corruption would be dropped bytes at either end
> of the connection. This should be pretty detectable by the IP checksum.
Exactly -- the carrier link should be clean, given that the modems are
working correctly. Now assuming the modem-host cables are short, and
shielded, this connection should be clean too. The most likely problem
will be in the host's async interface, and I know for a fact that the
NetBSD-1.0/i386 driver will get overrun errors on many systems, even
with 16550's. The damn i386/i486 is just too slow at processing
interrupts, and the driver has just too much code in it.
> corrupt IP packets. I'd say it would be rare indeed for a corrupt packet
> to pass the PPP CRC and the IP checksum, since these use different algorithms.
Any time there are huge numbers of IP packet errors there's something
wrong. I do agree that there are many types of errors which the current
version of TCP will not detect, but it should never come to that!
Greg A. Woods
+1 416 443-1734 VE3TCP robohack!woods
Planix, Inc. <firstname.lastname@example.org>; UniForum Canada <email@example.com>