Networks

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Table of Contents
 * ===Notes===
 * Computer Networks
 * Hardware Required On A Network
 * Software required to operate on a network
 * Intranets and Encryption
 * ===Assignments===
 * Questions
 * Internet
 * What is LAN\WAN?
 * BUILD A NETWORK:
 * questions
 * ===[{$page}#homework|Homework]]===
 * [Replace this with homework heading and date due i.e. Complete Worksheet 3 (3/23/2010)]

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** Computer Networks **
a) describe a modem and its purpose; b) state the difference between analogue data and digital data; c) describe the need for conversion between analogue and digital data; d) identify the advantages and disadvantages of using common network environments such as the Internet; e) describe what is meant by the terms user id and password, stating their purpose and use; f) identify a variety of methods of communication such as fax, e-mail, bulletin boards, and tele/video conferencing; g) define the terms Local Area Network (LAN) and Wide Area Network (WAN); h) describe the difference between LANs and WANs, identifying their main characteristics; i) describe the characteristics and purpose of common network environments, such as intranets and the Internet; j) discuss the problems of confidentiality of data, including problems surrounding common network environments; k) identify the need for encryption and authentication techniques when using common network environments such as the Internet.

HARDWARE REQUIRED ON A NETWORK:

 * File server:It's a computer responsible for the central storage and management of data files so that other computers on the same network can access the files.
 * Print server: A device that connects printers to client computers over a network.
 * Hub/Switch: A device for connecting multiple devices in a network.
 * Router/USB Modem:It's a device that modulates an analog signal to encode digital information, and also demodulated such a carrier signal to decode the transmitted information. (Modulator-Demodulator).
 * Workstation: It's a computer intended for individual use that is faster and more capable than a personal computer.
 * Network cable:It's a cable used to connect one network device to other to connect two or more computers to share other components (printer,scanner..)
 * Network card:A piece of computer hardware that is designed to allow computers to communicate over a network.

**Software required to operate on a network**

 * File system software:** A file system (or filesystem) is a means to [|organize] data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device(s) which contain it.

**5 applications that are network aware**


 * 1) Web browser:** to look for certain information on various sites all over the net.


 * 2) Email client:** account which allows the user to send, and receive, messages.


 * 3) Videoconference program:** (such as Skype) to allow users to communicate audiovisually with other users around the world.


 * 4) DNS (Domain Name System):** it translates domain names meaningful to humans into the numerical identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide.


 * 5) Anti-virus:** used to prevent viruses to access a personal computer, by having access to the files and; eventually, invading an entire network.

Intranets and Encryption

 * 1) It’s a private network based on internet standards but only available within a business or other organizations. The intranet is restricted unlike internet. Used to: place revision guides, homework, students can share work; can communicate with teachers to resolve doubts…
 * 2) Extranets allow authorized outsiders limited access to an intranet.

ENCRYPTION:

Encryption is the proccess of converting information into a form that is meaningless to anyone except holders of a "key".

NETWORK AND DATA SECURITY:
 * Physical security
 * Username and good password
 * Install and use a firewall
 * Data encryption

Assignments
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Questions
Modem is a device that converts the digital signals from a computer into analogue signals that can be sent down the phone line.
 * What is modem, what does it do?**

How you can connect to the internet?
Dial up - Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a dialled connection to an Internet service provider (ISP) via telephone lines. ISDN - Integrated Services Digital Network (ISDN) is a set of communications standards for simultaneous digital transmission of voice, video, data, and other network services over the traditional circuits of the public switched telephone network. ADSL - Asymmetric digital subscriber line (ADSL) is a type of digital subscriber line technology, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide.

Internet
What is internet? The **Internet** is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve billions of users worldwide. It is a //network of networks// that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support email.

What is username and password? Username-A **user** is an agent, either a human agent (**end-user**) or software agent, who uses a computer or network service. A user often has a **user account** and is identified by a **username** (also **user name**), **screen name** (also **screenname**), **nickname** (also **nick**), or **handle**, which is derived from the identical Citizen's Band radio term. Password- A **password** is a secret word or string of characters that is used for authentication, to prove identity or gain access to a resource (example: an access code is a type of password). The password should be kept secret from those not allowed access.

What is LAN/WAN?
A **local area network (LAN)** is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building. The defining characteristics of LANs, in contrast to wide area networks (WANs), include their usually higher data-transfer rates, smaller geographic area, and lack of a need for leased telecommunication lines.

A **wide area network** (WAN) is a telecommunication network that covers a broad area (i.e., any network that links across metropolitan, regional, or national boundaries). Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations. In essence this mode of telecommunication allows a business to effectively carry out its daily function regardless of location.

BUILD A NETWORK:


Workstation: A computer intended for individual use that is faster and more capable than a personal computer. 1000Gb Switches: Switches with 1000GB of capacity.-A device for connecting multiple devices in a network. File server: A computer responsible for the management of data fles so that other computers on the network can access the files. Firewall (web cache): It's a set of related programs located at a network gateway server, that protects the resources of private networks from other networks. Router (3Mb connection to internet): Modulator-Demodulator of analog signals or digital signals. Cat5e cable: It's a cable that supports 1000Mb or gigabit. Tape drive: It's a device that stores computer data on a magnetic tape.


 * QUESTIONS:**

1) What hardware is needed to connect a stand alone computer onto a network? (two items) Network Interface Card and a switch.  (2)  2) Draw a diagram of a star network and label the hub and server.

(2) 3) To connect a computer to the internet you need to use a modem. Explain what a modem is and why a computer needs a modem to connect to the Internet?  A modem modulates digital signals, or other digital devices into analog signals. Because in order to use an analog telephone lines you need to convert the signals from digital to analog and vice-versa.  (3)  4) There are different ways to connect to the Internet. Explain the difference between a dial up connection and ADSL. Mention 3 differences. Dial up is to convert the digital signals to analog signals. ADSL is permanently connected and uses another type of technology which doesn’t require modulation. ADSL: Is faster, can use telephone line at the same time as internet and it’s permanently connected. (3) 5) To connect to the Internet you need an ISP. What does ISP stand for, what does it do and give an example of an ISP in Spain.  Internet Service Provider. Movistar, Vodafone, Orange. It provides internet services.  (3)  6) A family is thinking of connecting their home computer to the internet. a) // List and **explain** // three reasons why this would not be a good idea. Vulnerability to hackers, viruses can attack, if something gets damaged, the whole network fails.  (3)  b) List three advantages the family would gain from connecting to the Internet. Participate in world wide services, can play online games, access to a wider range of information. (3) 7) On a common network environment such as a school network, how can individual users keep their work safe from other users?  Users can save their data in their own space with a username and password.  (1)  8) A company wants to set up a video conference with a sister company in the USA. List three pieces of hardware that are required? Webcam, microphone and NIC (also speakers, monitor, modem or router…) (3) 9) Explain the difference between a LAN and a WAN and give examples of when each one may be used.  LAN is a network geographically situated in a small area, connecting nearby computers (school, office…). A WAN is a network geographically located over large distances, usually it’s various LANs connected together (Internet, large world wide business…).  (2)  10) A school has just installed a new network. Along with new hardware required, new software is also required. Explain the function of the printer server software and the file server software. The printer server software is were the workstations are connected to share a common printer. A file server keeps the files safe; it’s only accessible with a username and password. Also manages files. (4) 11)  a) List **//__and__//** **explain** five reasons why a large company with over 100 employees should install a network in their office. They are going to be able to share files and data easily and quickly. Can share devices within the network. Workers can share their work via e-mail to be more productive. Money is saved are most resources (hardware and software) are shared. (5) b) List two precautions this company should take and **//explain why//**?  Encryption to avoid unauthorized people to read the data. Closed the doors to prevent unauthorized people physically accessing the workstations.  (2)  12) A company has just set up online shopping, whereby its customers can buy its products on the Internet. What precautions does it need to take to ensure that its customer’s financial details are safe? Explain your answer. They could use a username with strong passwords, to avoid people from accessing the information. Encryption (encrypt the sensible info), for people to not recognize the writing. Use a firewall to avoid hackers from accessing the information. Physical security, locking doors were computers are in.

Homework
media type="custom" key="5239321" . [Replace this with homework heading and date due i.e. Complete Worksheet 3 (3/23/2010)] ARDWARE REQUIRED ON A NETWORK:
 * File server:It's a computer responsible for the central storage and management of data files so that other computers on the same network can access the files.
 * Print server: A device that connects printers to client computers over a network.
 * Hub/Switch: A device for connecting multiple devices in a network.
 * Router/USB Modem:It's a device that modulates an analog signal to encode digital information, and also demodulated such a carrier signal to decode the transmitted information. (Modulator-Demodulator).
 * Workstation: It's a computer intended for individual use that is faster and more capable than a personal computer.
 * Network cable:It's a cable used to connect one network device to other to connect two or more computers to share other components (printer,scanner..)
 * Network card:A piece of computer hardware that is designed to allow computers to communicate over a network.