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Internet Printer Protocol
Ok, I don't own a printer, but some of you guys might
still use that outdated paper thing. Here is an article about
the
Internet Printer Protocol (IPP)
which is being touted now as the latest greatest in allowing
people to print over the internet. Odd. I did it all
the time when I was writing papers and stuff.
Let's start with the title: ``Printers to get their own Web addresses'' Umm, does that mean there will be a URL scheme to go with IPP?
That's exactly what it means. IPP Printers are referred to either as http:// for IPP v1.0, or ipp:// for IPP v1.1. In case you're interested, the TCP port pointed at by the ipp: scheme is 631.
How about ``A system administrator could manage his printers from a hotel room.'' Haven't these guys heard of lpq(8)/telnet(1)? Geesh.
Do you really want to expose those services over the public internet? Maybe if your printer supports ssh this will work, but with IPP you get management capabilities through a nice GUI (or text or however it's implemented) interface over a secure, authenticated connection.
Don't let this bit of CNN reporting dissuade you from IPP, however, because it looks like it will fix some of my pet peeves with Berkeley lpd(8)--namely, no decent authentication, no queue management in the protocol beyond deleting jobs, and no thought given to the actual format of the transported data (you've got to either use Postscript queues or raw text queues or use specific printer drivers on all clients).
IPP will support several authentication schemes, depending upon the client and server platforms.
IPP lets you specify the document-format attribute in the print job; it can be PostScript, pcl, text, printer driver output (e.g "octet-stream" type), or whatever other MIME types the printer supports. The printer will intelligently reject unsupported document formats sent to it, and you can query the printer ahead of time as to what it supports.
It should be noted that most expensive printers with network connections already support LPR and many support a strange feature where you can `print' HTML files (it's called ``Web printing'').
That's still supported in IPP (via the print-URI operation). Unfortunately not every OS supports lpr, and as you've pointed out there are big flaws in lpr that make it difficult to use over public networks.
I once worked at Adobe in the PostScript group. We were experimenting with printers that had an HTTPd server embedded in them. The printer had its own webpage displaying toner reserves, job-queue status, any recent error conditions, etc.
... a webpage for your car (mechanical & fluid status) a webpage for your cellphone (how many calling-minutes so far this month)... a webpage for the coke machine down the hall (been there, done that :)
Also, there were pointers to the manufacturer's webpage so that you could reorder supplies, get questions answered, and so on. To me, this seemed to be the perfect integration of "dumb" devices and the power of the WWW. I'm glad to see that, at least for printers, there is an evolving standard for this stuff.
Think a bit and extend the idea: disk drives with a webpage (giving usage stats, error rates)
Stan
I like the general concept of this idea, I cannot comment on the way it is being done, but the idea is a great one. See, I am a firm beliver in OpenStandards. I like to use many different OSes, and many different apps. When one does not play well with others, it ruins my day. That is why I love html, plain text, mpeg, wav, jpeg, etc. I can use any of those formats, and use them on any OS I happed to be in front of that day.
Now, we could argue if this standard is being done right, but that will not accomplish anything. Lets insted be happy with the fact that people are working towards another cross-platform technology. And if you do not like the way this one works, draft up your own ideas, I am sure people would be more then happy to look at them.
Sometimes I get the idea that people would rather sit back and complian about the work of others, and not do anything to make it better. That is what is great about the internet, you don't have to be someone important to have a good idea that people latch onto.
Elwood
I don't know about this being all that great of an idea. I imagine that the same type of people who go around using Back Orifice for kicks would also find it amusing to hunt down people with open printers who don't realize they're open and either waste their paper by printing a hundred sheets with one word in the middle or waste their ink by printing a few completely black pages. Since it seems that most people I know who have computers don't know about 80% of what they can really do, it seems that a lot of people wouldn't realize their printers were open to pretty much everybody.
-mike kania
Am I the only one that leaves my printer off unless I'm printing something? This is useful ..
IPP is host to a slew of problems, the worst of which is the lack of access control. Fax machines already suffer badly from junk faxes, and legislation had to be put into effect to try and deter that behavior. (Please correct me if I'm wrong... The rapidly changing legislation on privacy vs. free speech gets the better of me sometimes.)
:)
From the cursory glance I gave HP's site of IPP a couple weeks ago, it didn't look like there was much of a standard for access control on the system. I mean, receiving a 100 page email is one thing -- you can delete it, and it doesn't use much in the way of material resources. However if someone uses IPP to send you a 100 page piece of junk, even if it's accidental (typed in the wrong ip?), it can cost quite a bit... Especially if it's a nice color transparency printer!
I'm all for standardizing printing protocols, but I really think IPP needs a little more work before it becomes mainstream. For now, I'm quite happy spooling stuff to port 515 on my printers
Taral
WARN_(accel)("msg null; should hang here to be win compatible\n");
-- WINE source code
The 1.0 IPP specifications are available in PDF or in TXT formats. I'll post more once I've read them myself...
Scott Severtson
Software Developer
Auragen Communications
scotty@auragen.com
Scott Severtson
Senior Architect, Digital Measures
The links above are just for the IPP URL naming convention. Check out http://www.pwg.org/ipp/ for a full list of documents that are available.
Scott Severtson
Software Developer
Auragen Communications
scotty@auragen.com
Scott Severtson
Senior Architect, Digital Measures
- IPP is secureThe protocol specifies that Transport Layer Security (TLS) Version 1.0 will be used to provided mutual authentication and encryption. Elsewhere in the documents, (optional) compression can be applied as well.
- IPP is complexWith support for multiple document protocols, multiple documents per "job", and a fairly detailed client querying process, it also won't be cheap.
- Document protocols are specified as MIME types, and they define a couple recommended ones: PCL, Postscript, HTML, and plain text.
- Documents can be sent as a URI (i.e. an HTTP URL), which, if the IPP server supports it, can be used to go out and retrieve the document when the printer is available to print it, instead of holding it in spool.
- Multiple configurations are specified, with just waiting to be created. For example, IPP allows a printer with an embedded spooler and internet interface, a printer hooked to a spooling server with an internet interface, and multiple printers hooked to a spooling, smart server with an internet interface, which routes the document to the printer best suited/least busy for the job.
- Supports extended properties for client querying. The single biggest advantage of the system is that the client does not have to have any idea of what type of print it is printing to, i.e. no more specific printer drivers. Instead, the client connects to the printer/spooler, asks it what it can do, and sends the document in a compatable format. This should (hopefully) save a lot of hassle in the work place for configuring printers on thousands of desktops.
Just my two cents.Scott Severtson
Software Developer
Auragen Communications
scotty@auragen.com
Scott Severtson
Senior Architect, Digital Measures