Subject: Re: KA655 on-board ethernet; was: Re: Bragging Time...
To: Olaf Seibert <rhialto@polder.ubc.kun.nl>
From: Johnny Billquist <bqt@Update.UU.SE>
List: port-vax
Date: 02/18/2000 17:33:26
On Thu, 17 Feb 2000, Olaf Seibert wrote:

> On Wed 16 Feb 2000 at 18:49:53 +0100, Johnny Billquist wrote:
> > That I don't understand. ftp uses tcp, which includes a checksum. You
> > shouldn't be able to get bad packets up the stack then. This really sounds
> > weird. Are you sure you don't have a memory problem instead?
> 
> Well, the UDP and TCP checksums are not actually very *good*. Just
> (one's complement) sums, that's all, not CRCs. Fairly high risk of
> undetected errors.

True. But it's not that likely that you'd get that many errors anyway.
One single-bit error in a packet will be detected. A stuck bit would most
likely also always be detected (hmm, I wonder if anyone have done any
checks on that?).

	Johnny

Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt@update.uu.se           ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol