Page 134 - Handout Computer Network.

For the remote control to function properly, you do not need to understand how the
remote-control functions electronically. The same is true of a web browser; the browser gives
you the capability to navigate through the web by clicking hyperlinks.

For the web browser to function properly, it is not necessary for you to understand how
the lower-layer OSI protocols work and interact.
6.3.3 Indirect Network Support

Within a LAN environment, indirect-application network support is also a client/server
function. If a client wants to save a file from a word processor to a network server, the redirector
enables the word-processing application to do so transparently.
Remember that this transparency is supplied by the session layer Remote Procedure Call
(RPC) functionality. A redirector is an OSI model session layer function that works with computer
operating systems and network clients instead of specific application programs.

Examples of protocols that use redirectors are as follows:

• AppleTalk Filing Protocol

• NetBIOS Extended User Interface (NetBEUI)

• Novell IPX/SPX protocols

• Network File System (NFS) of the TCP/IP protocol suite

A redirector enables a network administrator to assign remote resources to logical
names on the local client. When you select one of these logical names to perform an operation
such as saving a file or printing a file, the network redirector sends the selected file to the proper
remote resource on the network for processing.

If the resource is on a local computer, the redirector ignores the request and allows the
local operating system to process the request.

The advantage of using a network redirector on a local client is that the applications on
the client never have to recognize the network. In addition, the application that requests service
is located on the local computer, and the redirector reroutes the request to the proper network
resource, while the application treats it as a local request.

Redirectors expand the capabilities of non-network software. They also enable users to
share documents, templates, databases, printers, and many other resource types without having
to use special application software.
Networking has had a great influence on the development of programs such as word
processors, spreadsheets, presentation managers, database programs, graphics, and
productivity software. Many of these software packages are now network-integrated or
network-aware; they have the capabilities of launching integrated web browsers or Internet
tools and publishing their output to the Hypertext Markup Language (HTML) for easy web
integration.

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