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Lesson 4: Ensuring Hardware Compatibility

Networking is hardware-dependent, and not all hardware products are compatible. In Chapter 6, "Defining Network Protocols," we learned that in order for two computers to communicate, they must use the same protocol. Computer hardware raises similar issues. In some instances, two pieces of hardware simply can't communicate with each other. For example, consider an analogy to automobile parts: two parts might look alike and be able to perform the same function, but each is designed to work in a different car. This lesson examines the issue of ensuring hardware compatibility and what you can do to resolve incompatibilities.

When Hardware Is a Problem

Hardware incompatibilities are a fact of life. In today's computer industry, hundreds of manufacturers develop hardware and software. Each developer has a unique perspective on the best way to accomplish the same task, and each will provide a unique solution. Copyright and patent issues further complicate the matter.

Evaluating and selecting hardware is a major part of planning for network implementation. If you have the luxury of designing a network from the ground up, you can choose vendors and place the burden of compatibility on them. Before you make a purchase, give them a list of the hardware you plan to use and ask them to certify that those items are compatible with the vendor's products. Also, don't be too quick to accept one vendor's opinion. For example, if you are considering the purchase of two devices—X and Y—ask the vendors of X if their product is compatible with Y, and ask the vendors of Y if their product is compatible with X. Then compare the responses you get; they may help you to find an incompatibility you would otherwise fail to detect.

It is likely that you will have to create a network out of an existing collection of hardware. In such cases, the likelihood that problems stemming from incompatible hardware will arise is very high. It is sometimes more cost-effective to discard the old hardware and start over.

The most common incompatibilities occur between hardware and software. Changing or upgrading a computer or network operating system can lead to major problems. As discussed in the previous lesson, you might need to update hardware drivers at the same time you upgrade the software. Be sure to address this issue before you start.

Reading the Documentation

Read all the documentation about the products involved. Your hardware or software might have a recurring problem or might conflict with another product. Frequently, the manufacturer will document these conflicts and provide a fix. If you do not find the solution in the supplied documentation, you might contact the manufacturer of the product and ask for undocumented conflicts. Search the manufacturer's Web site for additional information.

Detection During Installation

When you install a new computer or network operating system, your computer will usually attempt to detect the hardware in the system during the installation process and load the appropriate drivers for it. Check the list of detected hardware and ensure that it matches what is already in the machine. If you are installing Novell's IntranetWare, for example, the install utility will automatically scan your computer for hardware such as hard disks, CD-ROM drives, and NICs. If the devices are recognized, the appropriate drivers will then be loaded for the recognized devices.

Checking Minimum Requirements

As a first step before you install, make sure that you exceed the minimum requirements for the resources in the computer. These resources include processor speed, memory, and disk space. Table 8.2 lists some minimum hardware requirements for common network software.

Table 8.2 Minimum Hardware Requirements for Network Software
 
NetWare 5 Windows NT Server 4.0 Windows 98
Processor Pentium processor 486 33 MHz or higher 486 66 MHz or higher
Memory 64 MB 16 MB 16 MB
Disk space 200 MB 125 MB 225 MB
Disk CD-ROM CD-ROM 3.5 high density
Monitor VGA VGA VGA
NIC YES YES YES

Remember that these are published minimum requirements. Treat these minimum requirements as you would, for example, treat a statement that a bicycle is the minimum requirement for riding up Pikes Peak. It can be done, but it would be much easier and a lot more fun in a powerful car. Windows NT Server with 16 MB of RAM will run and function in a 33MHz processor, but not quickly.

Network Hardware

Network hardware is not as susceptible as software to conflicts and compatibility problems. Chapter 7, Lesson 1: Connectivity Devices, covers the basics of how these devices (repeaters, bridges, routers, brouters, and gateways) work. These devices operate at the two lower layers of the OSI reference model (the physical and data-link layers). Since these devices are common to many different types of networks and work mainly with data packets, they are less likely to present conflicts. The manufacturers of these products maintain strict adherence to the IEEE 802.x standards. Therefore, any device that meets an IEEE standard can communicate with another device that meets the same standard. The only situation in which you can expect incompatibility issues to arise is when two devices meet different standards. For example, Ethernet and Token Ring networks use different methods of accessing the network. Therefore, a device designed to meet the 802.3 Ethernet standard will not communicate with a device designed to operate with the 802.5 Token Ring standard.


Exercise 8.4: Upgrading a Network

Knowing what we now know about network and computer compatibility issues, let's take a look at our bicycle company and see what, if any, problems we might encounter.

Assume that you and the Managing Director have decided that the best long-term solution is to install a server-based network. The director has also decided that she wants to base the network on Windows NT. Provide the answers to the following questions:

  1. Which resources do you anticipate are likely to present problems in the future and, therefore, should be upgraded or replaced?
  2. What do you suggest as the minimum operational requirements for equipment to be acquired in the future?
Answers

Lesson Summary

The following points summarize the main elements of this lesson: