Quiz 7

1.
Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information

Sending

device — initiates

instruction to

transmit data,

instructions, or information

Communications

device — connects

the sending device to

the communications

channel

Communications

channel — media

on which data,

instructions, or information level

Communications

device — connects

the communications

channel to the

receiving device

Receiving

device — accepts

transmission of data,

instructions, or

information

2.

  North/South Bridge

Memory controller

A computer is a miniaturized information highway.
All devices in the computer sends information back and forth.


3.

Users can send and receive wireless messages using wireless.

        Text messaging allows users to send and receive short text messages on a phone or other mobile device or computer

      Picture messaging allows users to send pictures and sound files

 Video messaging allows users to send short video clips

    Wireless instant messaging allows wireless users to exchange real-time messages with one or more other users

        Wireless Internet access points allow people to connect wirelessly to the Internet from home, work, school, and in many public locations

         A cybercafé is a coffeehouse, restaurant, or other location that provides personal computers with Internet access to it customers.

    A global positioning system (GPS) is a navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the GPS receiver’s geographic location.

4. List Advantages of using Network

• share software
• share information with others on networks
• share peripherals
• speed of sharing software and information files
• cheaper than buying individual software and hardware for each standalone especially if for a school, network software often offers deals for amount being purchased
• security, files can be copy inhibit mode
• centralized software management- software being loaded onto one computer but also this loads software to entire network at one time
• electronic mail(e-mail) between network users, ideal for office memos
• flexible access- access you files from any computer on the network unlike standalone which would mean only being able to access your data from the one computer you uploaded data 

 5.

A client/server

network

•  One or more computers act as
• server (host) and other
• computers, or clients, access
• server
•  Servers – control resources
•  Clients – rely on servers for
• resources
•  Dedicated servers

• servers, Network Server, Web Server
•  Efficient for 10 or more computers

Peer-to-peer

network

 Simple network that

connects fewer than

10 computers

 Each computer, or peer,

has equal capabilities

 Ideal for small business

Internet peer-to-peer

(P2P)

Next

 Sometimes called a file

sharing network

 Enables users to

connect to each other’s

hard disks and

exchange files directly

6.

Network Communication Standards

e Network standards defines:

 Way devices access the medium

 Speed on different types of networks

 Types of network technology (cable / wireless)

e Protocols

 Rules on how devices communicate with each other

 Data format used

 Coding Scheme

 Error Handling

 Sequencing techniques etc.

 Hardware / Software Vendors try to meet these guidelines

 ANSI, IEEE

 Standardizing Organization

Ethernet

 Standard that defines how devices are connected to LAN (bus or star

network)

 Device can transmit data only when the network is available to receive

data.

 If two devices attempt to send at same time collision occurs and should

be retransmitted

 Use cable to transmit data

 Original Ethernet – 10 Mbps

 Fast Ethernet – 100Mbps

 Gigabit Ethernet – 1Gbps

 10-Gigabit Ethernet – 10Gbps

 40-Gigabit Ethernet, 100-Gigabit Ethernet

Token Ring

 Standard for LAN (ring, star)

 Computers share / pass a special signal – token in

unidirectional manner

 Token – series of bits and functions like a ticket

 Whoever has the token can transmit the data

 Supports upto 72 devices

 Using special kind of wiring upto 260 devices

 Data rate – 4 Mbps, 16 Mbps, 100 Mbps and 1Gbps

What are TCP/IP

 TCP/IP (Transmission Control Protocol/Internet Protocol)

technology transmits data by breaking it up into small pieces, or

packets

 Packet – source, destination, sequence information, packet size etc.

 Checking and detecting error

 Sequencing

 Flow Control

• Packet switching : breaking a message, sending it throught best route, reassambling

IEEE 802.11, (Wireless Fidelity Wi-Fi) is a family of standards for

wireless LANs

How two wireless device communicate

Radio waves

Also known as wireless Ethernet

 Can communicate with Ethernet network

Coverage

• 100 ft. in closed area

• 300 ft. in open area

Bluetooth

- Short-range radio waves transmit data between Bluetooth devices

- Transfer rates : 3Mbps

- Coverage : 33 ft (10 m) upto 100 m with additional equipments

- smart phones, headsets, keyboards, digital cameras

- bluetooth adapter

UWB (ultra-wideband)

- short-range radio waves

- Coverage / Rate

10m (33 feet) – 110 Mbps, 2m (6.5 feet) - 480Mbps

- suitable for audio / video / picture files transfer

IrDA (Infrared data association)

- Use Infrared(IR) waves

- 115Kbps – 4 Mbps

- device must be in line of sight

RFID (radio frequency identification)

- radio waves

- specifies how a device communicates with a tag placed on person, animals, objects

- RFID tag (transponder) – memory chip + antenna.

- RFID reader (transceiver) reads the radio signal broadcast by the antenna ;

- Coverage 5 inches – 15 feet

WiMAX (Worldwide Interoperability for Microwave Access) IEEE 802.16

- WiMAX towers can cover up to 30 miles radius

- Fixed WiMAX Rate of transfer : 40Mbps

- Mobile WiMAX Rate : 15Mbps

WAP (Wireless Application Protocol)

- used by devices such as smart phones to display Websites, e-mail, chat rooms, instant

messengers etc.

7.

Communication software is used to provide remote access to systems and is also used to exchange messages in text, audio and video format for the purpose of communication. These software send and receive data over telephone lines through modems. The communication software allows computers in different geographical regions to communicate with each other through terminal emulators, file transfer programs, chat and instant messaging programs. 

8.

Telephone network (PSTN)?

 Worldwide telephone

system that handles

voice-oriented

telephone calls

 Can be used for data

communication as

Dial-up line
Next
 Temporary connection using telephone line for
communications
 Costs no more than making regular call
 dial-up modem




Dedicated line
Next
 Five types of digital
dedicated lines are
ISDN line, DSL,
FTTP, T-carrier line,
and ATM
 Always-on connection
between two
communications
devices


9.


Communications devices












Communications Devices


Dial-up modem
 A dial-up modem converts digital signals to analog signals and vice versa
 Usually in the form of an adapter card
•DSL Modem / ISDN Modem
•Send and receive digital data from DSL(Digital Subscriber Line) / ISDN
(Integrated Service Digital Network) line


•Cable Modem
 Sends and receives data over cable television (CATV) network
 Much faster than dial-up modem or ISDN
 Sometimes called a broadband modem


•Wireless Modem
 Allows access to the Web wirelessly from a notebook computer, a smart phone,
or other mobile device






Hub or switch


 Device that provides central
point for cables in network

Router

 Connects computers and
transmits data to correct
destination on network
 Routers forward data on
Internet using fastest available
path
 Some routers have a built-in
firewall


10.

Before you start: To decide what type of network to set up or to find out what hardware and cables you need. That topic has information about the different types of networks (also known as network technologies), as well as hardware requirements for each type.

Once you know what type of network you want and have the necessary hardware, there are four possible steps to take (two of these are not always required):

1.           Install any necessary hardware.

2.           Set up an Internet connection (optional).

3.           Connect the computers.

4.           Run the Set Up a Wireless Router or Access Point wizard (wireless only).

Each of these steps is described in detail later in this article.

Start by setting up one computer. Once you set up the network and you are sure that the first computer is working correctly, you can add additional computers or devices.

Note

This information is designed for people who have a broadband connection (usually DSL or cable) to the Internet rather than a dial-up connection.

Install the hardware

Install network adapters in any computers that need them. (Follow the installation instructions in the information that came with each adapter.)

Set up or verify an Internet connection (optional)

You don't need an Internet connection to set up a network, although most people want to use their network to share an Internet connection. To set up an Internet connection, you need a cable or DSL modem and an account with an Internet service provider (ISP). Then open the Connect to the Internet wizard and follow the instructions. For more information.

If you already have an Internet connection, you just need to verify that the connection is working. To do that, open your web browser and go to a website that you don't usually visit. (If you go to a website that you visit often, some of its webpage’s might be stored on your computer and will display correctly even if your connection is faulty.) If the website opens and you don't get any error messages, your connection is working.

Connect the computers

There are several ways to connect computers—the configuration depends on the type of network adapters, modem, and Internet connection that you have. It also depends on whether or not you want to share an Internet connection among all the computers on the network. The following sections briefly describe some connection methods.

Turn on all computers or devices, such as printers, that you want to be part of your network. If your network is wired Ethernet or HPNA, it should be set up and ready to use. You should test your network (see below) to make sure that all computers and devices are connected correctly.

Run the Set Up a Wireless Router or Access Point wizard

If your network is wireless, run the Set up a Wireless Router or Access Point wizard on the computer attached to the router.

·                 Open Set Up a Wireless Router or Access Point by clicking the Start button , clicking Control Panel, clicking Network and Internet, and then clicking Network and Sharing Center. In the left pane, click set up a connection or network, and then click Set up a wireless router or access point.

The wizard will walk you through the process of adding other computers and devices to the network. For more information.

Test your network

It's a good idea to test your network to make sure that all of the computers and devices are connected and working properly. To test your network, do the following on each network computer: Click the Start button , and then click Network. You should be able to see icons for the computer you are on and all of the other computers and devices that you have added to the network. If the computer you are checking has a printer attached, the printer icon might not be visible on other computers until you enable printer sharing. (Printer sharing is not available on Windows Vista Starter.)

Note

It might take several minutes for computers running previous versions of Windows to appear in the Network folder.

11.


Physical Transmission Media


Twisted-pair cable and coaxial cable?
Next
 Twisted-pair cable is used for telephone
systems and network cabling
 Separately insulated wires are twisted together
in a pair
 Twisting reduce the noise (disturbances)























 Coaxial cable is often used for cable
television wiring
 Single Copper wire in center
 Insulation
 Woven or braided metal
 Outer cover

Fiber-optic cable

 Hundreds of thin strands
of glass or platic
 Capable of carrying
significantly more
data at faster speeds
than wire cables
 Less susceptible
to interference
(noise) and, therefore,
more secure
 Faster transmission
 Smaller size (thinner
and lighter)
 Disadvantage : Costly and difficult to install