CUPS IPP JetPrint Printing socket

I think I cracked this CUPS thing

In a long ago post I think I complained about CUPS. Well, I’d like to retract some of that complaint.
Previously there were tremendous problems with CUPS. usually it would hang on printer jobs. It would report that a job had completed when it hadn’t. It would report a printer error then stop the queue. Then I discovered a gem on the CUPS website. Most LAN printers support IPP (Internet Printing Protocol) and Socket (aka JetPrint). I had all my LAN printers setup for IPP.
Now IPP should work just fine. But on a hunch I checked my LAN printers to see if they supported socket. The answer was YES! The CUPS documentation recommends that when possible use socket as it is the most reliable communication method ( . So I did just that. I entered the printers.conf file for each of my printers and changed them to use socket.
Wow! what a change. I now have (more) reliable printing. I have to say “more” because with the Windows RAW printing it still is not perfect – certain driver options are not passed through clean. So there is either:

  • A bug in IPP in my CUPS version (1.3.7)
  • A bug in the printers implementation of IPP
  • or both

The problem is more apparent with my MFP (KM Bizhub 250) with it’s special drivers and multitude of options. But I’m sure I’ll still find problems with the other printers. But at least CUPS is no longer dropping and get hung on jobs.

Gosh! how can IPP possibly work. It seems like an unreliable protocol. Can’t wait for Ubuntu 9.10 LTS for an upgrade on CUPS.