Internet Printing Protocol (IPP)

The Internet Printing Protocol (IPP) has gained high visibility as more computers become dependent on LAN as well as Internet resources. Although most network servers and clients can be configured to use the 1pr/lpd, Telnet, or DLC protocols, there are still many other protocols that can be used to send data to printers, such as SPX/IPX. The driving force of the Internet is making many vendors conscious of the need for more unified standards for basic functions, such as file and print sharing, and new protocols are being developed to meet those needs.

In 1996, several groups were developing a new standard. Novell and Xerox were working on a protocol that was titled Lightweight Document Printing Application (LDPA), IBM was developing the Hypertext Printing Protocol (HTPP), and Microsoft and HP were working on still another new protocol. Finally, a working group was formed under the auspices of the Internet Engineering Task Force (IETF) to work on a new standard. IPP uses the Hypertext Transfer Protocol (v. 1.1) as the underlying transport protocol.

The goals of the first) efforts of the project were to develop a protocol that defines the user end of the printing process and includes the following capabilities, as well as a few other features:

• Allow the user to discover the capabilities of a particular printer.
• Allow the user to submit jobs to the minter.
• Allow the user to get the status of the printer or a print job.
• Allow the user to cancel a print job.
• Define a set of directory attributes that make it easy to find a printer in a directory database.

All these are standard items incorporated into the first version of the standard (1.0).

Security and authentication mechanisms are also being created for IPP—just as for many other protocols that access the Internet.

The newest version of this protocol is 1.1. It is being developed by the RFC process, as well as the IEEE standards process. Following is a list of RFCs that have been written (as either a draft or an establishedstandard) for version 1.2 of IPP:

The work of the original IPP group so far was defined by several RFCs. Version 1.0 RFCs include thefollowing

• RFC 2565, "Internet Printing Protocol/1.0: Encoding and Transport"
• RFC 2566, "Internet Printing Protocol/1.0: Model and Semantics"
• RFC 2567, "Design Goals for an Internet Printing Protocol"
• RFC 2568, "Rationale for the Structure of the Model and Protocol for the Internet Printing Protocol"
• RFC 2569, "Mapping Between LPD and IPP Protocols"
• RFC 2639, "Internet Printing Protocol/1.0: Implementers Guide"

Version 1.1 of IPP is defined (at this time) by the following RFCs:

• RFC 2910, "IPP/1.1: Encoding and Transport"
• RFC 2911, "IPP/1.1: Model and Semantics"
• RFC 3196, "Internet Printing Protocol/1.1: Implementer's Guide"

Additional Internet Draft documents are still in the review stage and will add additional functionality to the protocol. For example, see also the following RFCs:

• RFC 3239, "IPP Requirements for Job, Printer, and Device Administrative Operations"
• RFC 3380, "IPP: Job and Printer Set Operations"
• RFC 3381, "IPP: Job Progress Attributes"
• RFC 3382, "IPP: The 'collection' Attribute Syntax"

Although standards bodies continue to refine and add new functionality to IPP, that has not stopped software vendors from using the protocol. If you want to keep abreast of newer developments in the IPP standards process, search for IPP at www rf c - editor . org, as well as the previously mentioned Web site of the IEEE working committee.