EOC Summary

1. What is a network, and what are the advantages of setting up one? A computer network is simply two or more computers that are connected using software and hardware so that they can communicate. Networks allow users to (1) share peripherals, (2) transfer files easily, and (3) share an Internet connection.

2. What is the difference between a client/server network and a peer-to-peer network? In peer-to-peer networks, each node connected to the network can communicate directly with every other node instead of having a separate device exercise central control over the network. P2P networks are the most common type of network installed in homes. Most networks that have 10 or more nodes are client/server networks. A client/server network contains two types of computers: a client computer on which users accomplish specific tasks, and a server computer that provides resources to the clients and central control for the network.

3. What are the main components of every network? To function, all networks contain four components: (1) transmission media (cables or radio waves) to connect and establish communication between nodes; (2) network adapters that allow the nodes on the network to communicate; (3) network navigation devices (such as routers and hubs) that move data around the network; and (4) software that allows the network to run.

4. What are the most common home networks? The two most common home networks are wired Ethernet and wireless Ethernet. Although waning in popularity, powerline and phoneline networks may still be an option in certain situations. The major difference in these networks is the transmission media by which the nodes are connected.

5. What are wired Ethernet networks, and how are they created? Ethernet networks use the Ethernet protocol as the means by which the nodes on the network communicate. This protocol makes Ethernet networks efficient but also slightly complex. Because of this complexity, additional devices (switches or routers) are required in Ethernet networks. To create a wired Ethernet network, you connect or install network adapters or NICs to each network node. Network adapters connect via cables to a central network navigation device such as a switch or a router. Data flows through the navigation device to the nodes on the network.

6. What are wireless Ethernet networks, and how are they created? A wireless network uses radio waves instead of wires or cable as its transmission media. Current wireless protocols provide for networks with up to a maximum of 108 Mbps. To create a wireless network, you install or attach wireless network adapters to the nodes that will make up the network. If the nodes are unable to communicate because of distance, you can add a wireless access point to the network to help relay data between nodes. Wireless networks are susceptible to interference from other wireless devices such as phones.

7. How are power-line and phoneline networks created, and are they viable alternatives to Ethernet networks? Power-line networks use the electrical wiring in your home to connect the nodes in the network. Phoneline networks move data through the network using conventional phone lines. To create either of these networks, you connect special network adapters to each node on the network. These adapters are then plugged into either an electrical outlet or a phone jack, and data is transmitted through either the electrical wires or the phone cable. Powerline and phoneline networks have relatively low throughput and cost more than Ethernet networks.

8. How can hackers attack a network, and what harm can they cause? A hacker is defined as anyone who breaks into a computer system unlawfully. Hackers can use software to break into almost any computer connected to the Internet (unless proper precautions are taken). Once hackers gain access to a computer, they can potentially (1) steal personal or other important information; (2) damage and destroy data; or (3) use the computer to attack other computers.

9. What is a firewall, and how does it keep my computer safe from hackers? Firewalls are software programs or hardware devices designed to keep computers safe from hackers. By using a personal firewall, you can close off to invaders open logical ports and potentially make your computer invisible to other computers on the Internet.

10. Why are wireless networks more vulnerable than wired networks, and what special precautions are required to ensure my wireless network is secure? Wireless networks are even more susceptible to hacking than wired networks because the signals of most wireless networks extend beyond the walls of your home. Neighbors may unintentionally (or intentionally) connect to the Internet through your wireless connection, and hackers may try to access it. To prevent unwanted intrusions into your network, you should change the default password on your router (to make it tougher for hackers to gain access), use a hard-to-guess SSID (network name), turn off SSID broadcasting (to make it harder for outsiders to detect your network), and enable security protocols such as WPA or WEP.

11. From which types of viruses do I need to protect my computer? A computer virus is a program that attaches itself to another program and attempts to spread itself to other computers when files are exchanged. Computer viruses can be grouped into six categories: (1) boot-sector viruses, (2) logic bombs and time bombs, (3) worms, (4) scripts and macros, (5) encryption viruses, and (6) Trojan horses. Once run, they perform their malicious duties in the background, often invisible to the user.

12. What can I do to protect my computer from viruses? The best defense against viruses is to install antivirus software. You should update the software on a regular basis and configure it to examine all e-mail attachments for viruses. You should periodically run a complete virus scan on your computer to ensure that no viruses have made it onto your hard drive.