DDP checksums

[Norman Goetz]

We have upgraded our FastPath code from 8.1.1 to 9.1.2, and
now cannot print documents from DEC machines running ULTRIX
to Imagewriters. FastPaths are 4s and 5s with 5.1 ROMs.
The Imagewriters show up fine with Chooser and print documents
from Localtalk without problem. The CAP software gives error
messages saying there is a DDP checksum error, and status
messages saying printer status cannot be obtained. The
checksum message is repeated 3 or 4 times (for the same packet?)
with the same received and calculated values, then again 3 or 4
times with a new set of values. Nothing is printed and this
pattern continues until aborted. The CAP code appears to be
finding the printer (NBP successful?) but the errors stop the
process.

There are more details that could be supplied. I have tried
turning off DDP checksums in the FastPaths, and cisco router
which is not in the path but is part of observed packet traffic.
Many packets are still being transmitted with something in the
DDP checksum field nevertheless.

Has anyone else observed:
problems upgrading to K-STAR 9.1.2?
problems turning DDP checksums on and off with Shiva Net Manager?
checksum errors with CAP printing to ImageWriter II or LQ?
problems with DDP checksums in LocalTalk -> Phase 2 conversion?

I will try calling Shiva, but they are closed today. Thanks
in advance for any hints or sympathy.
~r .signature