Basic Networking Concepts
Twisted Pair *
Fiber Optic *
Cable Type *
Other Required Devices *
Network Interface Cards *
Network Access *
Carrier Sense Multiple Access/Collision Detection *
Token Passing *
Ways to Network a PC *
Configuring Network Interface Cards *
Problems on the Network *
Reduced Bandwidth *
Networking is by far one of the most quickly expanding fields in the computer industry. With the surge in popularity of the Internet in the mid 1990ís, a great deal of interest in networking has arisen. Whenever two or more workstations are connected together, a Local Area Network (LAN) is created. Nearly every major company has, at a minimum, a LAN installed.
There are some basic networking concepts that you will run into time and time again as a technician. Whether you have an interest in networking or not, it will be in your best interest to be familiar with these basic concepts.
After you have a firm grasp of some basic networking concepts, it is also important to have a general understanding of how to configure a Network Interface Card (NIC). Configuration of a NIC is extraordinarily simple in most cases, and will be useful to you during your career.
Basic Networking Concepts
As a base for your networking abilities, you need to understand some basic networking concepts. Everything in the world of networking revolves around these concepts, and a firm grasp of them is extraordinarily important. These basic concepts include:
Network Interface Cards
Full Duplex Network Access
Obviously, in order to create a network, you have to somehow physically connect the devices that will be on the network. This is accomplished using cables. There are many different types of cables, each having itís own advantages and disadvantages. In the next few sections, we discuss three types of cabling: Twisted Pair, Coaxial, and Fiber Optic.
Twisted pair is by far the most common type of network cable, primarily because of its low cost. Physically, twisted pair consists of pairs of wires, usually four. Each of the wires in a pair is wrapped around the other to help avoid interference. Twisted pair requires that each workstation be attached to a hub (see Figure 1-1). A hub receives data from one of its ports, and then transmits it to all of its ports. Twisted pair cable is considerably less expensive than the other types of cabling. In larger network installations, the lower price of cable offsets the cost of a hub and makes twisted pair the most cost-effective networking solution.
Figure 1-1: A hub is a device to which each device on a network connects
Twisted pair can be referred to by many different names. Some of these names include unshielded twisted pair, UTP, shielded twisted pair, 10BaseT, or 100BastT; UTP is the most popular. As shown in Figure 7-2, twisted pair is configured in a star topology, in which each device is connected to a central device, usually a hub. In the event of a cable being cut or broken, the device that is connected to that cable will no longer be able to communicate on the network, but will not effect any other devices on the network.
Figure 1-2: A twisted pair network is usually configured in a star topology
Coaxial, while not as common as twisted pair, is also a popular type of network cable. Physically, coaxial cable consists of a central wire that is surrounded by a screen of fine wires. Coaxial cable is most common in smaller networks, where it is cheaper to purchase the coaxial cable instead of purchasing both the UTP cabling and hubs. Like twisted pair, coaxial can also be referred to by many names. Some of these names include BNC, ThinNet, and 10Base2; ThinNet is the most popular. Each device must be connected to a T-connector, shown in Figure 7-3. Each T-connector is connected to the next with a coaxial cable. After all of the devices are connected, the ends of the cable must then be terminated with a 50W terminator. As shown in Figure 7-4, a coaxial network is configured in a bus topology. In the event of the cable being cut or broken, the network will cease to operate.
Figure 1-3: A T-connector is required between each device on a network utilizing coaxial cabling and the coaxial cable
Figure 1-4: A coaxial network is usually configured in a bus topology with each device connected to a main cable or bus
Fiber optic is by far the least common of the three types of cabling. Fiber optic cabling is usually found where long cable lengths are required, where extremely high speed is desired (at extremely high cost), or where there is high EMI radiation or other environmental difficulties. Traditional copper-based cables such as twisted pair or coaxial cables are very susceptible to radiation and other environmental difficulties. Fiber optic cable is much less susceptible to these environmental difficulties because it uses light signals rather than electrical signals. Light signals offer much more protection from environmental interferences than electrical signals. Fiber optic is used when long lengths of cable are required because it is able to sustain longer distances without environmental interruption. Fiber optic is usually referred to simply as fiber. Each segment of fiber optic cable must be connected at each end with a special fiber optic connector. As shown in Figure 1-5, a fiber optic network is configured in a ring topology. In the event that the fiber optic cable is cut or broken, the network will cease to operate. (Most fiber optic installations actually include two rings in order to provide redundancy and fault tolerance.) Table 1-1 lists and compares each of the cable types discussed in this section.
Figure 1-5: A fiber optic network is usually configured in a ring topology where a token is passed around a ring
Table 1: Comparison of Important Characteristics of Cable Types
Network Interface Cards
* Carrier Sense Multiple Access/Collision Detection
Carrier Sense Multiple Access/Collision Detection
Ways to Network a PC So far, all of our discussion has involved using a NIC to connect two or more computers together. There are a few other ways to network workstations.
Ways to Network a PC
Dial-Up Networking is when a modem is used to connect two or more workstations together. The majority of people who connect to the Internet from home use Dial-Up Networking on a daily basis. It is considerably slower than using NICs, but can accomplish the same tasks.
A direct cable connection is when two computers are networked using either a serial or parallel cable. Direct cable connections are considerably faster than modem connections, but are still slower than networking using a NIC. Direct cable connections are limited to networking a maximum of two computers and are limited by physical cable restrictions.
Configuring Network Interface Cards
Problems on the Network
* Physically damaged cable
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