Lesson 16

Networks in Multi-Vendor Environments

Vendor?

Vendor = Seller

What is a multi-vendor Environment ?

A multi-vendor environment is a network where multiple operating systems are mixed.

For example, there may be servers running Novell Netware and severs running NT on the same network. There may also be Windows 95 and Apple Macintosh clients on that network.

(This is possible because all of these operating systems can work with industry standard low level protocols - such as Ethernet.)

It is Station / Server Communication That Important ?

Station to station communication is unusual. Virtually all network communication is between a station and a server, so we shall focus on the problem of a station / server communication between different systems.

The Challenge

The challenge is to make a client running one operating system talk to a server running a different operating system.

Solutions are implemented in two ways.

The Client Based Solution

In this solution we teach the client how to talk to its server. This is done using the redirector.

Consider our labs. Our clients are running MS Windows NT Workstation. Our servers run Novell Netware - a different system made by a different company.

We already know how this works. A redirector program, written and supplied by Novell, is loaded into the NT workstation.

This redirector does two jobs:

1. It redirects requests for remote resources out of the client and onto the network.

2. It translates. It converts the Windows NT request into a form that can be understood by the Netware server.

Note 1: There is no Novell client operating system - so all clients accessing a Novell server must be using an OS from a different vendor.

Note 2: Several redirectors can be loaded at the same time. One may map a drive on a Novell server to the letter G: Another may map a drive on an NT server to the letter P:. Each one translates the request so that it will be understood by the appropriate server, then redirects the request to that server.

The Server Based Solution

Here, we load software onto the server make it pretend to be a different kind of server. For example, to allow a Macintosh client to keep files on an NT server, we load the "Services For Macintosh" onto the server. This is software supplied by Microsoft that enables an NT server to look like an AppleShare server when accessed by a Macintosh client, yet continue to look like an NT server when accessed by NT clients.

For a summary of multi-vendor inter-connectivity see the table below:

Multi-Vendor Solutions

	MS DOS (& Windows 3.1)	Clients using only NetWare redirectors	Windows For Workgroups	Windows 95	Windows NT Workstation	Apple Macintosh
Novell Netware	Use Novell redirector	Use Novell redirector	Use Novell redirector	Load IPX/SPX protocol and "Microsoft Client For Netware Networks"	Load NWLink protocol and "Client Services For Netware"	Must load an additional ‘Macintosh’ module into the Netware server
Windows NT Server	Use NT redirector	NWLink + "File and Print Services For Netware"	Connects automatically - no extra software needed	Connects automatically - no extra software needed	Connects automatically - no extra software needed	Load "Services For Macintosh" on the server.
Apple Share	Use AppleShare Redirector	?	Use AppleShare Redirector		?	Connects automatically - no extra software needed

Notes:

1. The above table does not give the whole story. Further complications arise due to different file naming rules used with different operating systems. For example, the Apple Macintosh uses long file names but, by default Netware keeps to the 8.3 DOS convention. This is solved by loading a Apple ‘namespace’ system onto the server, before enabling Apple connectivity.

2. Remember that it is possible to have many variations on one network. For example, a network could have a Netware server and an NT server, plus DOS clients, NT clients and Apple clients - all connected into one system.

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