Chapter Five Network Types and More Troubleshooting What's Your Type?
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Chapter Five Network Types and More Troubleshooting What’s Your Type? Introduction In Chapter 4, we examined basic network connection troubleshooting. We followed that with a basic explanation of how network addressing works. Using a thought experiment, we saw how the address on a USPS package moves from the general to the specific. Then we looked at web URLs, discovering that in the same manner they moved from the general to the specific. A URL begins with the web server name, then points to the folder containing the desired document, and ends with the name of the specific file desired. The chapter ended with an introduction of IP addresses. Chapter 5 will build on that knowledge, finishing our look at troubleshooting and networks. Important Words in this Chapter ALT-F4 Internet Switch BSOD LAN Task Manager Ctrl–Alt-Del NUMLOCK WAN Data Packet Wireless Hub Router WLAN Network Types What are the two main network types? For what is LAN an acronym? How do we create a LAN? What is the special name given a LAN when it is wireless? What two network devices can be used to connect computers and create a LAN? For what is WAN an acronym? How do we create a WAN? What is the function of a network router? What is the largest WAN in the world? There are several network types, but for our purposes, I will just cover two of them. They are a LAN (Local Area Network) and a WAN (Wide Area Network). We will begin by examining a LAN (Local Area Network). The name pretty much describes what we mean. A LAN is a network connecting devices in a small area such as a school computer lab, a local library computer lab, a home network, or a business network. If a LAN is wireless, sometimes it is referred to as a WLAN (Wireless Local Area Network). Using a hub or switch (see Figure One, top of next page), we could connect four computers to create a LAN (see figure two, next page). The computers could communicate with one another and share files, but they would be unable to communicate with any other computers or get on the Internet. We create a WAN (Wide Figure 1 Network Hub (Above) Area Network) by connecting two or more LANs over a large area together. Think of a school system or business with several schools or buildings spread over several Figure 2 Simple LAN Using a Hub/Switch acres (or even cities or states), when they connect these separate LANs together, they have created a WAN. It is more complicated than this, but recall the hub we looked at earlier? Suppose I had two of them, each one in a separate state. Each one has three computers connected to it forming a local network or LAN. Then for the fourth port on each hub, I plugged in a long network cable running from one state to the other. We have created a WAN by connecting the two LANs (see figure three, next page). This example is simplified. For various reasons a single network cable cannot be run that far; moreover, there would be other network devices between Figure 3 WAN Made by Connecting Two LANs the hubs. One of the network devices found between would be a Router. Have you ever seen a picture of a police officer directing traffic at an intersection? That is what a router does on a network. The router looks at the destination address of the data packet and directs the packet out the connection leading to its destination. “What is the Internet?” Most of you have put two and two together by this point, “Yes, the Internet is an enormous WAN.” More Troubleshooting What does the acronym BSOD represent? Have you ever experienced a BSOD? What is the first course of action when experiencing a BSOD? What do you do when everything on the computer screen is frozen and the computer does not seem to be responding to the mouse or keyboard? If you have a frozen program and responsive keyboard, what are two commands you can use to close the frozen program and continue working? If everything but the mouse and keyboard are working, what are some things you can check and try, attempting to fix the problem? When you have no sound, what is the first thing to check if you have external speakers? Where is the speaker icon found? What is the fastest way to get to the Volume Mixer to adjust our sound levels and mute/unmute channels? Sometimes you turn your computer on and everything works just fine. However, after a while something stops working, or when you open another program you experience problems. In the following paragraphs, we will look at potential solutions to some of these common problems. Let us begin with Figure 4 BSOD Screenshot perhaps the worst thing that can happen, the BSOD (Blue Screen of Death) (see figure four). There is not a lot you can do in this situation except reboot or restart the machine. You may have to turn the computer off manually to be able to reboot. To do this, push the power button in and hold down for 5-to-10 seconds. The computer will shut down. Release the power button and wait about 10 seconds, allowing the computer’s hard drive to spin down, before pressing the power button to restart the machine. If the BSOD continues to occur, this is a sign of serious problems and more than a simple fix. (For more information, check out “Blue Screen of Death Survival Guide: Every Error Explained,” at http://www.maximumpc.com/article/features/blue_screen_survival_guide , see figure five). Stepping down the list, suppose everything on the monitor is frozen; moreover, both the keyboard and mouse Figure 5 BSOD Survival Guide Webpage do not seem to be responding. Tap the NUMLOCK key (see figure six), found above the number keypad. Notice if the NUM LOCK indicator Figure 6 Numlock Key & Light light goes on and off while you tap the key. If it does, then the computer has not completely locked up. You might wait two- to-three minutes and see if the computer sorts itself out. If the NUM LOCK indicator does not cycle on and off while you are tapping the NUMLOCK key, then the computer is frozen. You will need to reboot the computer. (Just follow the rebooting directions found in the BSOD section above.) Figure 7 ALT F4 Example If you have an unresponsive program, with a working keyboard there are two things you can try to close the frozen program. Hold down the ALT key and press the F4 key [ALT+F4] (see figure seven above). This should close the window in which you are currently working. You may lose what you were working on. Some programs make timed backups of what you are working on and when you reopen them may say there is a recovered document. Open the recovered document and see if you want to save it. Figure 8 Location of Keys for CTRL-ALT-DEL The second thing you might try in this situation is holding down the Ctrl-Alt buttons together and pressing DEL (i.e. the three-fingered salute). (See figure eight above.) For future reference, find this on your keyboard. Depending upon Figure 9 Windows Task Manager your windows version, this will open either the Task Manager, or a menu allowing you to open the Task Manager. (See figure nine.) (Depending upon the options set by your Network Administrator, you may not have access to the Task Manager.) Task Manager will list any programs not responding and give Chief Engineer David Bradley of the IBM PC Project was responsible you the option to shut them down. If neither for the design of the Ctrl-Alt-Del function. Created for use during of these options works, you might try development, public use was unintended. A writer forgot to remove it from the technical documentation logging out of your account and then logging and thus it was revealed to the public. back in. When that fails, or is unavailable, follow the directions in the BSOD paragraph above for rebooting. What do you do if the mouse or keyboard individually does not work, but everything else seems to be working? Swap the offending device or try plugging it into a different computer. In this way, you can isolate the problem to either the computer or the input device. (Did you remember basic troubleshooting from Chapter 3? Check the cables and connectors for the mouse and keyboard. Make sure the cables are good and the connectors secure.) I saved the simplest for last. Everything works, but there is no sound. If you have external speakers, your first action is to check the related cables and connectors. If this does solve the problem, or you do not have external speakers, find the speaker icon on your taskbar in the lower, right side of your screen. (See figure 10.) Right click on the icon, bringing Figure 10 Speaker Icon up the sound menu (See figure 11), open the Volume Mixer (See figure 12), and unmute any controls that are muted. You may also need to slide the volume controls up. Sometimes you may need to go into the Playback devices part Figure 11 Sound Menu of the menu and making sure to select the correct output device. Most of the time, this will fix your problems. Conclusion This chapter began by examining LANs and WANs. This information, when combined with information from earlier chapters, left you with a basic understanding of how a network and the Internet Figure 12 Volume Mixer work.