Planning a Network

In the previous lessons, you learned about using the world's largest computer network, the Internet. You have studied the basic principles of networks, examined the World Wide Web, looked at other areas of the Internet, and discussed ways to make your network and computers connected to the Internet more secure and to ensure yourself the safest online experience possible. You are almost ready to pull everything together to create your own network. The last remaining step before that is to do some initial planning.

In this chapter, you will examine different types of networks and begin planning all of the steps necessary to create your own network.

What Kinds of Things Can I Share on a Network?

As you've learned throughout the course, networks offer many things that make your life simpler and keep you more in touch with those around the world than ever before. Popular uses of networks include:

  • File sharing
  • Sharing equipment, such as printers, fax machines, and scanners
  • Connecting to the Internet
  • Playing games

Networks are as crucial to information sharing as streets are to transportation. Now that you understand the basics, you can examine some specific functions of a network. Understanding what you want from a network is essential when setting up a network.

Can we share files?

You can use a network to share a variety of files with other people. You can share documents you create, sound files stored on your hard drive, pictures you create in a graphics program. You can also share certain programs so that you only need to keep one copy of the software on the server.

Before networks were available, people would copy files to floppy disks to share them. This is known as sneaker net and is still a common method of sharing files. However, transferring files over the network protects the data, eliminates the risk of copying information to a disk that is easily damaged, and reduces the likelihood of introducing a virus to the system.

If you connect to someone else on the same network, or to a computer on a different network, you can even share files by dragging and dropping the files between folders, as if you were moving them around on your own computer.

Can we share printers?

In addition to sharing files and programs online, you can also share resources such as printers and scanners. Before networks, each computer had to be connected to its own printer. Now, you can connect a printer to the network and all the other computers on the network can print documents using that single printer.

In addition to printers, you can share other resources as well. It is common to share a scanner, backup equipment, fax machine, or hard drives.

Can we share an Internet connection?

With the popularity and importance of the Internet, it is important that all computers on a network have Internet access.This is possible by setting up an Internet connection for the network, with all computers accessing the Internet through the local network.

There are two basic methods for connecting a network to the Internet: using a router or a modem. A router is a piece of equipment that connects networks and directs, or routes, information to computers on the network. The router offers a connection between the network and the Internet. Figure 5-1 shows a router.

Figure 5-1:

Router

A modem is a piece of equipment that connects a computer to the Internet via a phone line. When used with a network, the network connects to the modem, and then the modem dials up the server at the Internet Service Provider (ISP) and makes the connection. Common ISPs include national companies such as MSN, AT&T, and Earthlink, as well as thousands of local companies.

A dial-up modem, once the only option for going online, is now considered outdated by most corporations. They are slow and many of the newer technologies, such as streaming video, do not work well over a modem. Figure 5-2 shows an internal modem.

Figure 5-2:

Internal Modem

Are there other things we can do over a network?

Many of the same things you can do on the Internet you can do over a private network. For example, you can set up email between computers on the network and you can play games between computers on a network. Many colleges offer network access from dormitory rooms. You can sit in your room and connect to the library without needing to go to another location to do your research. Once you are part of the workforce, you will find networks make it possible for you to work from home or on the road by connecting to the office network. The possibilities are really only limited by your resources.

Getting a network setup and running requires some planning, then knowledge of hardware, software, cables, and more. In the rest of this chapter, you will examine putting the network together, and then you will put it all together and even connect the network to the Internet.

What Does It Take to Make a Network?

Before you can install a network, you need to do some planning. There are many experts in the field who believe planning is the single most important part of the process. Even in a small office or home network, you should do considerable planning. You need to consider such factors as size, speed, location, and cost. You will need to determine a design and whether you will need a server for a client/server system or connect the computers as peers. In this section, you will examine all of those questions.

What kind of network do I need?

The first thing you must do when designing a network is to determine exactly what kind of network you need. How many computers will you need to connect? If you have less than ten computers, can you use a peer-to-peer network or do you need a server to establish a client/server network? How do you plan to transfer the information between resources on the network? How will you lay out the network?

Network architecture

When designing a network, you need to consider how the information will be transferred between computers over the network. This is known as the network architecture. In large part, the architecture will determine the structure of your network, which you will examine below.

Every different type of network architecture has a set of standards, or protocols, that define how the information moves around the network. You might encounter four basic network architectures:

  • Ethernet architecture: the most popular and least expensive network architecture.
  • Token-ring architecture: often found in larger organizations, this is rapidly becoming an outdated network architecture.
  • ARCNet architecture: one of the oldest architectures
  • AppleTalk architecture: developed by Apple to control information transferred between Apple computers.

The most popular architecture today is Ethernet. Since it is the one most often used, you need to be familiar with ethernet and understand some of the basic concepts.

There are several different types of Ethernet and each one can send information across the network at different speeds. The most common Ethernet is 100BaseT, also known as Fast Ethernet. There is also Gigabit Ethernet, which can transfer information more than ten times faster than Fast Ethernet. An older standard, 10BaseT, is still common in small businesses and home networks. Ethernet networks are the imost inexpensive type of network architecture.

Network topology

Another important consideration is the structure of the network you want to install. The structure, also known as the network topology, is how the network is laid out and is usually dependent on the network architecture. This includes how the computers and the resources are placed physically and it also includes how the information is transferred between those computers.

There are four main types of network structures:

  • Star Bus
  • Bus
  • Ring
  • Hybrid
Star Bus networks

The most common type of network structure today is the star bus network. In a star bus topology, each computer connects to a central point on the network. Figure 5-3 shows a star bus network topology.

Figure 5-3:

Star Bus Network Topology

There are some advantages and disadvantages to each type of topology. The features of a star bus network include:

  • You can add computers to the central connector without shutting down the entire network.
  • Each computer and device connects to the central connecting device.
  • If there is a problem with one computer on the network, the other computers continue to function, although they would not be able to access anything on the problem computer.
  • The computers can be no more than 100 meters away from the central connector.
  • Each central connector can connect up to approximately 24 computers.
  • Star bus networks are a bit more expensive than other topologies since each computer must connect to a central connector and you usually need large amounts of cabling to make the network function properly.
Bus networks

A bus network is one in which all the computers connect along a continuous cable, known as a backbone. A bus network is popular with home networking systems or other small networks that connect only two or three computers. Figure 5-4 shows a bus network topology.

Figure 5-4:

Bus Network Topology

The features of a bus network include:

  • The simplest and cheapest network topology to create.
  • A single cable connects all computers.
  • Only one computer at a time can transfer information. The information travels along the cable and the recipient gathers the information from the cable.
  • You must add a terminator to each end of the bus network. When the cable gets to the last computer, it connects to that computer, and then the cable is terminated. This prevents the data from bouncing back through the network and interfering with newly sent data.
  • There is no need for a central connector.
  • It is not easy to add computers to a bus network. You must break the network connection to add a computer.
  • If one computer on the network causes problems, all computers on the network are impacted by the malfunction.
  • Usually uses coaxial cable.
Ring networks

A ring network features a single length of cable running between computers, which are configured in a ring. Ring networks are less popular today than in the past. Figure 5-5 illustrates a ring network topology.

Figure 5-5:

Ring Network Topology

Ring networks, once widely used, are less popular today because of some of the limitations of that topology. The information only travels in one direction, so when you send information to a specific computer, the information must travel through each computer first. The computer will check to see if the information is addressed to that computer. If not, it then sends it on down the line to the next computer, and so forth.This can make for slow transmission times. The features of a ring network topology include:

  • Computers are located close to each other.
  • There is no central connector.
  • There is no beginning or end to the network, eliminating the need for terminators.
  • Difficult to troubleshoot.
  • Network failure anywhere on the ring affects the entire ring.
  • It is difficult to add new computers to a ring network. You need to bring the cable to add the computer and everything will be offline until you get the new system installed and running.
Hybrid mesh networks

There are many variations on these basic topologies. Because you can combine different topologies in the same network, hybrid mesh networks have sprung up that combine at least two different types of topologies.

For example, you can connect multiple star networks using a single cable. This then creates a bus network with multiple star networks branching off from it. Figure 5-6 shows a typical hybrid mesh network.

Figure 5-6:

Hybrid Mesh Network

The features of a hybrid network topology include:

  • Networks between offices in different locations are often hybrids. The company might use a star bus network in the office in Seattle, and a bus network in the office in Atlanta.
  • You can connect different types of networks via a modem. For example, if you have a bus network at home, you can connect via a modem to your school network that uses a star topology.
  • Setup is difficult in hybrid networks because the configuration can get tricky when trying to make different topologies interact.
  • Hybrid networks, by their definition, are large, making them more expensive that a smaller, local network.
  • There are multiple communication paths, which help if there is a failure in one cable.

Other considerations

When you are planning the network, you need to look at other factors before you decide on the specific type of network. For example, you should consider:

  • Any existing equipment; if your home, school, or office already has a network and you want to upgrade it, or you have specific computers available, you need to understand what is possible with your existing equipment.
  • Network size; if you have only a couple of computers, a peer-to-peer network is a possibility, whereas if you are connecting more than ten computers, you will need to focus on a client/server network.
  • The amount of information you want to share; the type and amount of information you plan to share can impact the type of network you need. If you are transferring large files, such as music, video, or graphic files, you will need a network that lets you share large amounts of information at a faster speed.
  • Physical location; where you plan to put the computers is important. If you have computers on different floors of a building, you will need to look at the best configuration for the computers and the best network topology for the space.

What hardware do I need?

Once you have examined your needs and know the type of network you want to install, you are ready to consider the type of hardware you need. Hardware is the physical equipment that makes up your network, such as the computers, monitors, printers, and connection devices.

Network servers

If you have decided to use a peer-to-peer network, you will not need a server. A server is a vital component, however, of the client/server network. A server is a powerful computer that fills a specific function on the network. You might have a dedicated server to store files, to hold web pages, to handle email, and to backup your files. Figure 5-7 shows a typical network server.

Figure 5-7:

Network Server

When you choose a server, you need to consider the following:

  • Expandability; the ability to grow as your needs change and expand.
  • Speed; the performance of a server is directly tied to the amount of memory and the speed of the chips, or Central Processing Units (CPUs).
  • Memory; servers require more memory than a regular computer. You can add memory as your needs grow; however, it is generally a good idea to add as much memory as possible within the budget to start. The more memory the server has, the more efficient the server will run.
  • Storage devices; most servers run large programs and handle massive amounts of data, so you should include enough storage capacity.
  • Storage; network servers are generally very large machines and they need to be in an area where they do not get too hot, where they aren't prone to accidental damage, and where there is not too much humidity.

Storage devices

A large network usually will include a file server to store information. The file server requires large enough and reliable enough storage devices to hold the information securely.

Storage devices can include:

  • Hard disk drives; these are the primary storage device found on a file server and in most other computers
  • Tape drives
  • CD-ROM and DVD-ROM drives
  • Optical drives
  • Network storage

Network printers

Networks offer the advantage of sharing printers. Rather than needing one printer for each computer, multiple computers can share a printer. The type of printer on the network depends on the size of the network. For a home system, an ink jet or small laser printer is probably sufficient. On larger networks, there may be multiple laser printers and there is usually a print server. The print server is a computer that manages and stores all the print jobs sent to the printer from all the computers on the network. The print server receives print jobs, prioritizes them, and then sends the output to the correct printer.

Network Interface Cards (NICs)

A network interface card (NIC)is installed inside each computer and connects the computer to the network cable. The NIC, as shown in figure 5-8, controls the information passing between the individual computer and the network.