Chapter 8
Boosting Network Performance

•  Understanding The OSI Network Model

•  Understanding The Windows NT Network Model

•  Understanding Network Topologies, Segments, And Technologies

•  Creating A Wide Area Network Using The Remote Access Service

•  Understanding Firewalls And Proxy Servers

•  How To Improve Network Performance

Designing a perfect network on paper is easy. Building a perfect network in reality is impossible, simply because nothing is perfect in the real world. Designing and building a good network, however, is well within the scope of the average person. All it takes is an understanding of basic network concepts and the technology used to implement these concepts to build a functioning network. In fact, this is where we will start—exploring basic network concepts. We will explore the OSI and Windows NT network models, supported network protocols, network topologies, network segments, and general network technologies. By the time we finish our discussion on basic network concepts, you will have a good understanding of exactly what a network is and how it operates.

After we cover the basics, we’ll look into Wide Area Network (WAN) technologies and how to implement a WAN using the Windows NT Remote Access Service (RAS). Then, we will discuss firewalls and proxy servers. This will provide you with a basic understanding of these technologies and explain why you might want to implement one on your network. Finally, we’ll discuss some of the options you can use to improve network performance. This includes installing multiple network adapters and configuring them for best all-around performance. By the time we wrap up this chapter, you will be equipped with the knowledge you need to design, implement, and tune your network. So, let’s start from the ground up and discuss some basic network concepts.

Network Concepts

A thorough understanding of network concepts is helpful in determining how to efficiently build a network. We have a lot of ground to cover in this section, so let me outline our path for you. We will start our discussion with an introduction of the International Organization for Standardization (ISO) Open System Interconnect (OSI) network model. Then, we’ll discuss the Windows NT architectural network model and how it differs from the OSI model. This information will help you better understand how your network actually works and aid you later in your administrative duties when it comes time to troubleshoot your client-connectivity problems.

We will then move on to a discussion of the various network protocols supported by Windows NT. You can consider a protocol as the language a computer uses to communicate over the network. One thing to keep in mind is that, before one computer can communicate with another computer, both computers have to use the same protocol, or language. Just as we communicate using the English (German, Spanish, or other) language, two computers must use the same protocol, such as NetBEUI, IPX/SPX, or TCP/IP, to communicate. Choosing the right network protocol is important, because your choice will impact how efficiently your network will perform as well as determine your network’s ability to communicate with other non-Windows NT-based networks.

Finally, we will discuss the various components actually used to build your network. This includes the network topology, network segments, and network technology. The network topology determines how a network is physically designed. Network segments define how networks are subdivided. Network technology determines the actual cabling and network adapters available to connect your components.

The OSI Network Model

The OSI network model is a theoretically perfect model that few manufacturers actually follow. I have included it here because it is a good place to start our discussion and will be helpful when we look at the implementation of the Windows NT network model. The OSI model breaks up the actions required by a computer network into seven separate layers, or modules if you prefer, as shown in Figure 8.1. The topmost, or application, layer defines how individual programs interact with the network. The lowest, or physical, layer defines the network cable and other physical attributes of the network. The model’s design requires that each module only communicates with the module directly above or below it. This provides the ability to replace an individual module as long as the module’s exported functions remain the same.

Figure 8.1  The seven layers of the OSI network model.