How Network Printing Works

Printing has an interesting place in the seemingly long history of PC networking (although it has only been a little more than 20 years ); the ability to share printers, along with file sharing, was one of the key reasons personal computers were networked in the first place. A shared printer on a network is a printer that accepts print jobs from more than one computer.

When you connect a printer to a server on the network and configure it to share print resources with users on the network, it is referred to as a print server . Different terms are also often used to designate where the printer is actually located on the network.

A local printer is a printer that is directly attached to a server. The printer is only local, however, in relation to the server that it is attached to. This server will, obviously, serve as the print server for the printer.

A remote printer is a printer attached to a computer other than your server, which can be pretty confusing because the computer that the printer is attached to would consider the printer local. Whether a printer is local or remote will depend on which computer on the network you are using as your reference point.

A third type of network printer also exists: the direct connect printer. A direct connect printer is a printer that contains its own network interface, processor, and memory for print serving. These printers are typically attached directly to a network hub or switch using twisted-pair cable, just like any computer on the network.

Printers without direct connection hardware can be attached to devices (made by a number of vendors ), such as the Hewlett-Packard JetDirect external print server, and then connected directly to the network. The external print server provides at least one parallel port for connecting the printer and a CAT 5 Ethernet port for connection to the network hub.

Now that we know the different categories of printers that can be found on the network, we can discuss how network printing actually works. When a user prints a document from a network client using application software to a network printer, the redirector on the client machine sends the data out onto the network to the print server computer that controls the particular network printer.

The print server uses software called a print spooler to accept the print job and place this job in its print queue , which is just some of the computer's memory used to hold print jobs until they can be sent to the printer. When the printer is free to accept the print job, it is released from the print queue.

As with creating shares on the network, how printers and print servers are configured for network printing will vary depending on the NOS you are using. Check out Chapters 8, 9, and 10 for information on how to provide printing in the NetWare, Windows Server 2003, and the Linux environments, respectively.

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Several printers can be configured to be part of a printer pool , which is basically a group of printers (identical printers that use the same driver software) that is seen by the network as just one printer. Because multiple printers actually make up the one print resource, you have a lot more muscle when it comes to handling a huge influx of print jobs from network users. The various print jobs will be parsed out to the printers in the pool as the printers become available.


The Absolute Minimum

This chapter provided an overview of network operating systems. We discussed how servers and clients communicate related to shared folders and printers and we discussed some of the issues of running a NOS on the network.

  • A network operating system, or NOS, is software that allows a computer to "serve up" resources to network clients. The NOS also provides the central access point for a network and requires users to log on.

  • Calls for resources on the network are handled by the redirector, which is part of the client software. It actually fools the client into thinking that remote shares and printers are actually connected locally.

  • Each NOS product has been tested on a variety of hardware. Hardware that works with the NOS will be found on the network operating system's hardware compatibility list.

  • A network share is a drive or folder on a server that is made available to network users.

  • Printers can be shared on the network. This shared resource is managed by a print server. Print jobs sent to network printers are accepted by the print spooler software and placed in the print server's print queue.



Absolute Beginner's Guide to Networking
Absolute Beginners Guide to Networking (4th Edition)
ISBN: 0789729113
EAN: 2147483647
Year: 2002
Pages: 188
Authors: Joe Habraken

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