TS+Computer+Networks+and+Troubleshooting



Tech Support: Computer Networks and Troubleshooting
By **hthstech**

Computer Networks
**Connecting Computer Systems** **Two Main Types of Networks** **1. Peer-to-Peer Networks** (or P2P) **P2P Advantages**
 * A network is a group of computers that are connected in order to share resources (files, printers, etc.)
 * The sharing of resources is called networking
 * A computer network needs at least two computers connected but, often consists of more than two.
 * The school is part of a network
 * Your U: is network space because you can access it from anywhere in the building
 * Reduces peripheral (anything that connects to a computer) costs like printers, scanners, etc.
 * Networks are not limited to a building or campus
 * The Internet is the ultimate network
 * 1) Peer-to-Peer Networks
 * 2) Client/Server Networks
 * A network is referred to as Peer-to-Peer if most computers are similar and run workstation operating systems:
 * In a peer-to-peer network, each computer holds its files and resources.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Other computers can access these resources but a computer that has a particular resource must be turned on for other computers to access the resource it has.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">For example, if a printer is connected to computer A and computer B wants to printer to that printer, computer A must be turned On.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">In this case, each connected computer would play the role of a client (access information) and a server (stores information).
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Limewire is an example of Peer-to-Peer software used for “sharing” files.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">When you search something within the Limewire program, you are actually searching the hard drives of other people who have the program installed and when they search, Limewire checks your computer as well.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">No need for a network administrator.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Network is fast and inexpensive to setup and maintain.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Each computer can make backup copies of its data to other computers for security.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Peer-to-peer is, by far the easiest type of network to build for either home or office use.
 * < [[image:mrsturgeon:p2p.gif caption="P2P"]] ||
 * < P2P ||


 * < [[image:mrsturgeon:p2p2.png caption="Peer-to-Peer"]] ||
 * < Peer-to-Peer ||

**Client/Server Networks** **Client/Server Advantages**
 * < [[image:mrsturgeon:peer3.gif caption="You can also use a hub or router"]] ||
 * < You can also use a hub or router ||
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">A computer network is referred to as client/server if (at least) one of the computers is used to “serve” other computers referred to as “clients”.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">This would mean that the server’s sole function is to store file or helps clients reach other resources such as printers
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">One of the particularities of a client/server network is that the files and resources are centralized.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">This means that a computer, the server, can hold them and other computers can access them.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Since the server is always On, the client machines can access the files and resources without caring whether a certain computer is On (like accessing file on your U: in the library even though you created them in the tech lab).
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Another big advantage of a client/server network is that security is created, managed, and can highly get enforced.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">To access the network, a person, called a user must provide some credentials, including a username and a password.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">If the credentials are not valid, the user can be prevented from accessing the network.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">The client/server type of network also provides many other advantages such as centralized backup, Intranet capability, Internet monitoring
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Faster for sharing large amounts of data.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">More reliable (dedicated server).
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Higher level of security.

<span style="color: #cc0000; font-family: impact,Verdana,Arial,sans-serif; font-size: 2.5em; text-decoration: none; vertical-align: baseline;">Computer Network Assignment 1:
Complete the assignment below using the information above or other websites.

[|Tech Support Network Assignment.doc]

<span style="color: #cc0000; font-family: impact,Verdana,Arial,sans-serif; font-size: 2.5em; text-decoration: none; vertical-align: baseline;">Internet vs. World Wide Web
The Internet is the world’s largest network. 1. **World Wide Web (the Web)** 2. **Electronic Mail (E-mail)** 3. **File Transfer Protocol (FTP)** 4. **Voice Over Internet Protocol (VOIP)**
 * Internet Components Include:**
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">a system of interlinked, hypertext documents (WebPages) that run over the Internet
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Browser required (Internet Explorer, Firefox)
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">A **Web browser** is a software application which enables a user to display and interact with text, images, videos, music, games and other information typically located on a Web page at a Web site on the World Wide Web or a local area network.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Web browsers format HTML information for display, so the appearance of a Web page may differ between browsers
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Modern e-mail systems are based on a store-and-forward model in which e-mail computer server systems, accept, forward, or store messages on behalf of users
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Users connect to the e-mail infrastructure with their personal computer or other network-enabled device for the duration of message transmission or retrieval to or from their designated server.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">**FTP** is a network protocol used to transfer data from one computer to another through a network such as the Internet.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">commonly used for uploading webpages to the appropriate webspace
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Is a general term for a family of transmission technologies for delivery of voice communications over networks such as the Internet
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">It enables audio chat over MSN, Skype, etc.

<span style="color: #cc0000; font-family: impact,Verdana,Arial,sans-serif; font-size: 2.5em; text-decoration: none; vertical-align: baseline;">**The Birth of the Internet**
.com : Commercial
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Began in the 60’s during the Cold War
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Came from U.S. Department of Defense having a need to establish links between military locations in case of nuclear war
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Major universities were also involved (University of California (U of C) +Massachusetts Institute of Technology (MIT)
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">No anticipation of how large this project would grow
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">More access points added in the 70’s,
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Some were domestic (in the home) and abroad (international)
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Domain Name System (DNS) introduced in 1984 instead of IP addresses (used text like www.yahoo.com instead of a series of #s)
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Domain names often end with country codes like .CA, .AU
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Can also be non-profit like .ORG or commercial (a business) like .COM
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Grew extensively in the 80’s.
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">1990’s saw the net explode for business use
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">By 1995, advertising, online banking, and even pizza deliveries were common
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Late 90’s saw streaming video (like youtube.com videos)
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">JAVA and Active X took advantage of higher connection speeds for things like online games (miniclip.com)
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">By year 2000, domain names became a business opportunity as people bought up names in hope of selling them to parent companies
 * <span style="font-family: inherit; font-family: inherit; font-size: 12px; font-size: 12px; vertical-align: baseline; vertical-align: baseline;">Top domain extensions as of July, 2006:

.net : Networks

.org : Organizations

.edu : Educational

.gov : US Government

.int : International Organizations

.mil : US Dept of Defense

.pro : Professionals

.biz : Businesses

.info : Informational