Section Objectives
After you complete this section you will:
Understand the types of networks.
Explore which network you should implement.
Understand what a network protocol is.
Be able to identify different network cables.
Understand the different types of network equipment.
Identify different types of network cards.
Understand what duplex is.
This portion of the exam requires knowledge of basic network concepts and terminology, ability to determine whether a computer is networked, knowledge of network cards and their installation, and the ramifications of repairs when a computer is networked.
This portion of the tutorial covers Domain 6.0: Basic Networking.
Topics recommended for study by CompTIA are:
- Installing and configuring network cards
- Network access
- Full-duplex, half-duplex
- Cabling – Twisted Pair, Coaxial, Fiber Optic, RS-232
- Ways to network a PC
- Physical Network topographies
- Increasing bandwidth
- Loss of data
- Network slowdown
- Infrared
- Hardware protocols
What is a network?
When more than two computers are linked together it forms a network. There are three types of networks: Local Area Network (LAN), Wide Area Network (WAN), and Metropolitan Area Network (MAN).
The most common two types of network you will come in contact with are the LANs and the WANs. A Local Area Network is one which is confined to a small general geographic area. A Wide Area Network is one which spreads over a large area.
For example, your company’s office may have a LAN installed in your building. This is the network which all of your computers and peripherals are installed on. It may then connect to a WAN which comprises all of your satellite offices around the world.
A Metropolitan Area Network (MAN) is a network which is comprised in one geographic metropolitan area. For example, a city may have setup a MAN for its networking requirements.
There are generally two different broad types of networks, the peer-to-peer network and the server-based network.
A peer-to-peer network consists of a series of workstations (desktop or laptop PCs) connected together with no central file or user management server. This is a common form of network in small offices. A common sign that you have a peer-to-peer network is that the individual computers share files and printers themselves and each user logs in locally to their computer. Commonly, a peer-to-peer network will use an operating system such as Windows 95, 98, ME, though it can be setup with other operating systems such as Windows 2000, Windows NT, Linux, or MacOS.
A file-server based network is one which has a central server at its core. A file-server network, when configured properly, has advantages over peer-to-peer networks including security and central management.
Which Type of Network Should I Implement?
If you have someone capable of administering a file server, a server based network is generally the most effective networking solution. This allows central management of security and file sharing. Central management of file sharing is critical when concerns of company secrets and document leaks are present. If you do not have an administrator capable of managing the central server, a peer-to-peer network will work fine in a small environment.
One position I held with a large multinational company involved integrating a merged company into the larger company. It was a very decentralized organization with several hundred sites and a LAN at each site. Unfortunately, over the years, the network had grown beyond the management skills of their Information Technology department. Originally they setup a peer-to-peer network at each location, then ended up opening the entire company up as a peer-to-peer network over their WAN. For ease of use, this was ideal. Anyone in the company could access any other employee’s computer making file sharing quite simple.
The problem came when a virus struck one of their computers. Unfortunately, most of the computers in that division never had anti-virus software installed, and if it did, it was years out of date. When the virus struck one computer, it looked for file shares on the network and within a few hours every computer in the enterprise had been infected! This virus was a destructive one and as we noticed the WAN traffic grow, we quickly identified the problem and shut down their network. It took us weeks and hundreds of thousands of dollars in consultant fees and software licenses to update and fix every
infected computer in the Enterprise.
Protocols
Networks communicate using protocols. A protocol is simple a method for the network to communicate, a way where all devices can talk the same “language”. TCP is an example of a protocol.
There are a couple of protocols you should be aware of for the exam:
TCP/IP: The most common communication protocol for networking. Acronym stands for Transmission Control Protocol / Internet Protocol.
Appletalk: A Macintosh standard protocol for communicating over networks. Often used in small Apple computer based networks, most news Macs just use TCP/IP.
IPX/SPX: Novell Netware used to be the standard for network servers and as such IPX/SPX, their proprietary protocol, was the dominant networking protocol in the late 80s and early 90s. Eventually, Novell was forced into using TCP/IP for their standard like everyone else.
Network Cables
There are three main types of network cabling: twisted-pair, coaxial, fiber optic. In addition, there is wireless networking.
Twisted-Pair
Twisted-pair, commonly called CAT5, is the least expensive and most popular type of network cabling. It is several pairs of copper wires twisted around each other in an insulated covering. 10BaseT networks primarily use twisted-pair cabling.
Coaxial Cabling
Coaxial cabling consists of a copper wire surrounded by insulation and a foil shield. It is often used for 10Base2 cabling. Coaxial cable is the same cabling you see used for “cable” TV.
Fiber Optic
Fiber optic cabling is designed to transfer data at very high rates and over large distances. It carries a light pulse through a glass core at speeds of 100 Mbps – 1 Gbps.
Wireless Networks
Wireless networks consist of several different types of transmission medium. It can use microwave, radio, infrared light, or lasers.
The most common types of wireless networks you will encounter are the 802.11b and 802.11a types of networks. 802.11 is a standard of the Institute of Electrical and Electronic Engineers, a standards setting body. 802.11a sets standard for 54 Mbps wireless networks in the 5 GHz range and 802.11b sets the standard for 11 Mbps wireless networks in the 2.4 GHz range (also known as WiFi). 802.11 sets the standard for 1 or 2 Mbps wireless networks operating in the 2.4 GHz range.
Other Types of Networks
Though you will probably not see this on the exam, it is good to know there are other types of network cables out there, mostly for the home arena. There are many inexpensive cabling solutions which rely on telephone wire or some which rely on the power lines inside your home. Though most businesses would not use these types of solutions, some homeowners are turning to them for inexpensive methods of networking computers together in their homes.
Network Equipment
There are several different pieces of network equipment that you should be aware of.
At each workstation, there is a network interface card (NIC). A NIC is a device which allows that workstation (or node) to connect to a network. There are many different types of network cards, though the most common is a 10BaseT Ethernet NIC.
Between each node, or between the nodes and central connecting device, there is the cable. The cable acts as the medium in which all of the data transfer occurs.
On most networks, there is a device which directs the traffic on the network. There are two devices which perform this functionality, a switch and a hub. A switch is a device which receives the packets of information and directs them to their destination. A switch does not share bandwidth between devices. A hub also directs traffic between devices, but it shares the packets of information with every port on the hub. The primary difference between a hub and a switch is that the packets are sent to every port (shared bandwidth) on a hub, while a switch directs the packets to the proper ports. A switch is preferred in most environments.
A gateway is a device which resides at the entry/exit point of a network to join to types of networks together.
A server can also exist on the network which is a central repository for information, user accounts, printer information, files, or any combination of these items. A server can simply be another workstation designated as a server with server software or it can be a full-blown server costing thousands of dollars with redundancy and more robust features than most PCs.
Types of Network Cards
There are two types of networking cards you should be aware of for the exam, though there are additional networking devices which we will cover in this tutorial for your general knowledge, though probably will not be on the exam.
Desktop/Workstation NIC Cards
The most common type of Network Interface Card (NIC) is the kind which works in a standard desktop or workstation. Typically, this card is a PCI based card which transmits at 10 Mbps or 100 Mbps. This type of card fits into one of the open slots on the motherboard of the PC.
Most major brand business computers (and a lot of home computers) now come standard with an Ethernet port. This port is the same that was contained on the former PCI cards, though the circuitry now simply resides on the motherboard of the PC.
Needless to say, each PC must contain a NIC card in order to participate on the network. In addition, each PC must contain the software it requires to communicate with the network.
PC Card NICs (PCMCIA)
When a laptop PC does not have a “built-in” network interface, you need to use a PCMCIA NIC to communicate on the network. These interfaces typically take up one PCMCIA slot on the computer.
Laptops with a built-in network interface have the circuitry built into the motherboard or a “daughterboard”. Confusing, a lot of the major manufacturers use built-in Ethernet ports which drivers say that are PCI Ethernet cards. Your typical PCI slot would contain a card too large for a laptop, though the PCI circuitry can be utilized anywhere.
Other Types of Network Connection Devices
There are a broad range of other devices which can connect you to the network. Most of these are either USB or Firewire based solutions.
Connection via RS232
It is possible to network two machines together via RS232, the serial port. Typically, you would use special software and a null modem cable to accomplish this. Due to speed, this is not a preferred method of networking.
Installing and Configuring Network Cards
Desktop/Workstation Based Computers
Installation of a network card in a desktop computer is fairly easy. You will need to remove the case of the computer and remove the slot cover on the slot you wish to insert the card into.
Press the card firmly into the slot and then screw the card into the case of the computer.
Laptop Computer
To install a PCMCIA network card into a laptop is simply the method of inserting any PCMCIA card into an open slot on the laptop. Depending on the operating system you are using, it is advisable to perform this function with the laptop powered off.
Duplex
Full Duplex
Full Duplex is a type of communication which can send data both directions simultaneously. For example, on a full duplex network one workstation can be sending data while another is receiving data at the same time.
Half Duplex
Half Duplex is a type of communication which can send data both directions, but not at the same time. For example, a workstation can send data and then immediately receive data, but cannot transmit and receive simultaneously.
After studying this section you should:
Understand the types of networks.
Explore which network you should implement.
Understand what a network protocol is.
Be able to identify different network cables.
Understand the different types of network equipment.
Identify different types of network cards.
Understand what duplex is.
