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From: bell@aussie.dec.com (Peter Bell)
Newsgroups: comp.dcom.lans
Subject: Re: DECnet problem/protocol question
Summary: Suspect the hardware
Message-ID: <13768@shlump.nac.dec.com>
Date: 24 Jul 90 16:50:32 GMT
Sender: newsdaemon@shlump.nac.dec.com
Organization: Digital Equipment Corporation
Lines: 27


In article <4084@dogie.macc.wisc.edu>, jrosen@vms.macc.wisc.edu (Jay Rosenbloom) writes...
>I'm trying to help someone copy a file between DECnet systems using the VMS
>COPY command and we are getting the message "-RMS-E-CRC, network DAP level CRC
>check failed"  when RMS closes the target file .  The source machine is a
[...]
>differences in some records so I believe that DAPs CRC check is working (i.e.
>the data really is getting corrupted).
[...]
>Can anyone explain why DAP appears to be detecting the errors and not an
>underlying transport layer?  It seems like the transport layer is not detecting
>bad packets and doing retransmissions.  Maybe it does, but it's just not
>effective.

The DAP CRC check is designed to detect any errors that occur at any point in
the copy. It will (most of the time) detect any memory/bus/adapter errors which
are otherwise unchecked on any machine through which the data passes.

As you are seeing errors on the same ethernet segment, then I would suspect
your hardware has a fault which is corrupting the data outside of the lower
level error checks.

>I'd really appreciate it if a DECnet guru could shed some light on 
>this!
>-Jay

Peter.  {DECnet guru?}