These are networks covering generaly a single site. The bandwidth available depends solely on the amunt you are prepaired to spend on purchasing the equipment used there are no ongoing charges based on the volume of information transfered.

If you are interested in paying a third party to transfer information between sites you should see the following article on WAN technology.

Topologies

The performance of a network is largely determinend by how the variouse eliments are joined together. Before spending your money on the latest technicle gizmo's apply a litte thought to the questions.

• Where is the data I want to share held?
• Where do I want to access it from?
• Can I make a better job of grouping clients and servers together?
• what bandwidth will be requiered?

10baseT

Devices are linked by hubs at a cost of around f

High Availability Cluster MultiProcessing

Distributed Computing environment {DCE}

A DCE environment consits of 1 or more DCE cells. Each cell contains 1 or more computers, which between them provide the the following sevices at all times.

• Cell directory server.
• Security server.
• Distributed time server {at leased 3 recomended}.

AIX 4.2.1

AIX 4.2.1 includes most client moduals for a DCE environment and the basic DFS server moduals. Additional functionality is available by ordering one or more of the folowing components.

5765-C35 IBM Distributed file system starter kit

5765-533 IBM DCE Security services

Prerequisites :-

DCE Base Services

5765-534 IBM DCE Cell directory services

Prerequisites :-

DCE Base Services

5765-532 Getting started with DCE for Aplication developers

Includes :-

DCE Tools

5765-639 IBM Directory and Security server

Includes :-

• DCE Base services
• DCE Security Services
• DCE Directory Services
• DCE tools

Distributed file system {DFS}

With DFS you have a primary server and one or more caching servers.

When access is attempted to a file on a caching server, Its time stamp is compaired to that on the primary server and a replacement copy fetched if it is out of date.

This works well for large collections of infrequently changed files such as would commonly be found on a web server. but is unsutable database aplications where you have a few large and frequently modified files.

Preqequisite:-

• DCE Cell Directory service.
• DCE Distributed Time service.
• DCE Remote procedure call.
• DCE Security service.
• DCE Threads.

DCE Distributed Time service

Preqequisite:-

DCE Security services