Subject: Re: hardware IP checksumming etc...
To: None <netbsd-users@netbsd.org>
From: Wolfgang Rupprecht <wolfgang@wsrcc.com>
List: netbsd-users
Date: 06/05/2001 08:32:22
thorpej@zembu.com (Jason R Thorpe) writes:
> Sure, but there are plenty of cheap hubs/switches that screw it up in
> a way that makes a corrupted/packet appear OK.

I don't think you have to even look that far.  Early pizza-box Suns
(around the 3/60 era) when hooked together on a 10base-2 would get a
few UDP checksum errors while having good ether CRC's.  Now that was
scary.  Clearly the packet got trashed somewhere between main memory
and wherever the LANCE slapped the CRC on (internally to the chip).

I also know of an un-named router box that had the same problem.
Someone blew the design for the bus logic and packets didn't always
make it to the ethernet chip intact.

-wolfgang
-- 
       Wolfgang Rupprecht <wolfgang+gnus@dailyplanet.wsrcc.com>
		    http://www.wsrcc.com/wolfgang/
Coming soon: GPS mapping tools for Open Systems. http://www.gnomad-mapping.com/