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Communications and NetworksInternet Resources

+Unit Objectives

After completing this chapter you will be able to: Discuss the purpose of the components required for

successful communications and identify various sending and receiving devices

Describe various uses of computer communications List the advantages of using a network, and differentiate

among LANs, MANs and WANs Differentiate between client/server and peer-to-peer

networks, and describe how P2P networks work

+Unit Objectives

Differentiate among a star, bus, and ring network Describe the various network communications standards Explain the purpose of communications software Describe commonly used communications devices Discuss different ways to set-up a home network Describe various physical and wireless transmission media

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CommunicationsCommunications and Networks

+Communications

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

Today, even the smallest devices can communicate with each other – often via the Internet

+Communications

For successful communications you need: A sending device that initiates an instruction to transmit

data, instructions or information A communication channel or transmission media on which

the data, instructions, or information travel A communication device that connects the communications

channel to a receiving device that accepts the transmission

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Uses of CommunicationsCommunications and Networks

+Uses of Communications

Computer communications are everywhere Many require that you subscribe to an Internet access

provider With others, organizations such as a business or school

provide the communications services

+Summary of Communications Previously Discussed

Communications Previously Discussed

Blogs Newsgroups

Chat Rooms RSS

E-Mail Video Conferencing

Fax VoIP

FTP Web 2.0

Instant Messaging Wikis

+Wireless Messaging Services

Users can send and receive wireless messages to and from smartphones, cell phones, and handheld game consoles using three techniques Text messaging Picture/Video messaging, and Wireless Instant Messaging

The type of messaging depends on the on the services offered by your wireless Internet service provider, or WISP

+Text Messaging

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

Services allow the user options to send and receive: Mobile to Mobile Mobile to E-Mail Web to Mobile, and Mobile to Provider

+Picture/video messaging

With picture messages users can pictures and sound files, as well as short text messages, to another device

With video messages users can send short, about :30, videos is addition to other type of messages

Smart phones and other devices using MMS, typically have a built-in camera As a consumer, you should be aware of memory availability

and camera quality

+Wireless Instant Messaging

Wireless instant messaging (IM) is a real-time communications service that allows mobile devices to exchange messages with other online users

Some WISPs partner with IM services AT&T allows communications through AIM, Windows Live

Messenger, and Yahoo! Messenger

+Wireless Access Points

People connect everyday to wireless access points using their mobile devices to access Internet-based services

Two Types: Hot Spots, & Mobile Wireless Networks

+Hot Spots

Is a network that provides wireless Internet connections to mobile devices

Three technologies Wi-Fi (local, within a building or room) WiMax (regional, withing a community) Bluetooth (location-based hot spots)

Some hot spots are free, schools & coffee shops, and some are subscription-based

+Mobile Wireless Network

Provided by cell phone companies, for their devices to access their networks

Coverage and speed depends on the carrier

Most common speed is 3G “4G” networks are becoming available

+GPS

Short for Global Positioning System

Uses satellite triangulation to pinpoint a location usually within 10-100 meters

Examples Smart phones Car Navigation systems Handheld systems for hiking

Access to additional features

+Geocaching

Geocaching is a real-world outdoor treasure hunting game.

Players try to locate hidden containers, called geocaches, using GPS-enabled devices and then share their experiences online.

www.geocaching.com

+Collaboration

People use the Internet to collaborate, or work together online

Methods of collaboration E-mail Collaborative Software Document Management Systems

+E-mail

Oldest form of collaboration

Users send information and documents back and forth through their e-mail accounts

Pros Quick and inexpensive

Cons Creates multiple versions of a document Information can get lost in the mix

+Collaborative Software

Tools that enable users to share documents via online meetings and communicate with other connected users

Sometimes called a Web Conference or Web Meeting

Examples Microsoft Groove or Office Live Meeting WebEx Google Apps GoToMeeting

+Document Management Systems

Provides storage and management of a users documents

Users can be granted access to each others documents Only one document exists, not multiple versions

Examples Windows Live SkyDrive Google Docs

+Cybercafés

Also know as an Internet Café, is a location, usually a coffeehouse or restaurant, that provides Internet access to its customers

Examples Starbucks Burger King McDonalds

+Web Services

A Web service is a method of communication between two electronic devices over the web. The service can be integrated into any web page so users

can easily access it They do not require a specific programming language,

operating system or web browser

Examples Google Apps, Google Cloud Print, Office 365

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NetworksLANs, MANs, and WANsNetwork ArchitecturesNetwork TopologiesIntranets

+Networks

A network is a collection of computers and devices connected together via communications devices and transmission media

A network can be internal to an organization or span the entire world

Why network? Facilitating communications Sharing hardware Sharing data and information Sharing software Transferring funds

+LANs, MANs, & WANs

Networks can be classified is three categories1. Local Area Network

2. Metropolitan Area Network

3. Wide Area Network

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Local Area Network (LAN)A network that connects computers and devices in a limited geographical area, such as a home, computer lab, or office building

+WLAN

A wireless LAN is a LAN that uses no physical wires

Computers and devices that access a WLAN must have built-in wireless capability, or an appropriate adapter

Very often WLANs are setup side-by-side with a traditional LAN

+Metropolitan Area Network (MAN)

A high-speed network that connects local area networks in a metropolitan area such as a city or town

A MAN typically includes one or more LANs but covers a smaller geographic area then a WAN

Managed by a Network Provider such as a state government, telephone company, or cable provider

+Wide Area Network (WAN)

Network that covers a large geographic area, such as a city, country or the world

A WAN can be one large network or consist of two or more LANs

The Internet is the worlds largest WAN

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Network ArchitecturesThe design of computers, devices, and media in a network, sometimes called network architecture, is categorized as either client/server or peer-to-peer

+Client/Server

On a client/server network, one or more computers act as a server, and the other computers request services from the server

A server, sometimes called a host computer, control access to the hardware, software, and other resources on the network

The clients are other computers or mobile devices on the network that rely on the server for its resources

+Peer-to-Peer

Simple, inexpensive network that typically connects fewer than 10 computers or other devices

Each computer, or peer, has equal responsibilities and capabilities

Each computer stores files on its own hard drives for sharing

Ideal for very small businesses and home networks

+Internet Peer-to-Peer

P2P describes an Internet network on which users access each other’s hard disks and exchange files

Sometimes called a file-sharing network

Examples: BitTorrent Gnutella Kazaa LimeWire

Responsible for the majority of illegal file-sharing on the Interent

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Network TopologiesStarBusRingIntranets

+Network Topologies

A network topology refers to the layout of computers and devices in a communications network

Three most common topologies:1. Star

2. Ring, and

3. Bus

Most networks, including the Internet, use a combination of the three

+Star Network

All of the computers and devices, called nodes, connect to a central device, usually called a hub or a switch

All data is transferred through the hub or switch

Fairly easy to install

Nodes can be added and removed without affecting the rest of the network

Hub/SwitchNode

+Bus Network

Consists of a central cable to which all computers and other devices connect

The bus is the physical cable that connects everything

Popular because they are inexpensive and easy to install

Devices can be added, removed, and moved with ease

If the bus fails, the entire network goes down

Bus

Node

+Ring Network

A cable forms a closed loop, or ring, with every device

Data travels from device to device on the ring until it reaches its destination

If one device fails, the entire network could possibly go down

Node

+Intranets

An intranet is an internal network that uses Internet technologies

Intranets usually make company information accessible to employees

Examples: Telephone directories Event calendars Job postings Video conferencing

Accessed through a web browser where changes can be made by everyone

+Network Communication StandardsEthernetToken RingTCP/IPWi-FiBluetooth

UWBIrDARFIDWiMAXWAP

+Network Communication Standards

Today’s networks connect a variety of devices across many different networks, such as wide area, local area and wireless.

All networks must use similar techniques for connecting devices to ensure compatibility

Two regulating organizations1. ANSI

2. IEEE

These organizations propose, develop, and approve network standards

+Network Communications Standards

A network standard defines guidelines that specify: The way computers access the medium to which they are

attached, The type(s) of medium used, The speeds used on different types of networks, and The type(s) of physical cable and/or the wireless technology

used

A that standard outlines characteristics of how two networks communicate is called a protocol

+Widely Used Standards & Protocols

You are to choose a standard or protocol below to research on a and report to the class1. Ethernet

2. Token Ring

3. TCP/IP

4. Wi-Fi

5. Bluetooth

6. UWB

7. IrDA

8. RFID

9. WiMAX

10. WAP