McGraw-Hill/Irwin © 2008 The McGraw-Hill Companies, All Rights Reserved

Business Plug-In B5Business Plug-In B5

Networks and Networks and TelecommunicationsTelecommunications

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LEARNING OUTCOMES

1. Compare LANs, WANs, and MANs

2. List and describe the four components that differentiate networks

3. Compare the two types of network architectures

B5-3

LEARNING OUTCOMES

4. Explain topology and the different types found in networks

5. Describe TCP/IP along with its primary purpose

6. Identify the different media types found in networks

B5-4

Networks and Telecommunications

• Telecommunication system - enable the transmission of data over public or private networks

• Network - a communications, data exchange, and resource-sharing system created by linking two or more computers and establishing standards, or protocols, so that they can work together

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Network Basics

• The three types of networks include:

– Local Area Network (LAN)– Wide Area Network (WAN)– Metropolitan Area Network (MAN)

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Network Basics

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Network Basics

• Networks are differentiated by the following:

– Architecture: peer-to-peer, client/server– Topology: bus, star, ring, hybrid, wireless– Protocols: Ethernet, Transmission Control

Protocol/Internet Protocol (TCP/IP)– Media: coaxial, twisted-pair, fiber-optic

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Architecture

• There are two primary types of architectures

– Client/Server network

– Peer-to-peer (P2P) network

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Client/Server Network

• Client - a computer that is designed to request information from a server

• Server - a computer that is dedicated to providing information in response to external requests– Client/server network - model for applications

in which the bulk of the back-end processing takes place on a server, while the front-end processing is handled by the clients

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Client/Server ComputingClient/Server Computing

Processing Processing split between split between client & server client & server machinesmachines

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Client/Server Networks

• Client/Server network

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Client/Server Networks

• Network operating system (NOS) - the operating system that runs a network, steering information between computers and managing security and users

• Packet-switching - occurs when the sending computer divides a message into a number of efficiently sized units called packets, each of which contains the address of the destination computer

• Router - an intelligent connecting device that examines each packet of data it receives and then decides which way to send it onward toward its destination

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Peer-to-peer Network

• Peer-to-peer (P2P) network - any network without a central file server and in which all computers in the network have access to the public files located on all other workstations

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Peer-to-Peer (P2P) networkingPeer-to-Peer (P2P) networkingP2P is form of distributed P2P is form of distributed processing that links processing that links computers via the computers via the Internet or private Internet or private networks, so that they networks, so that they can can share processing, share processing, memory and storagememory and storage. . Each computer acts as Each computer acts as both its own client and both its own client and server.server.

Examples : Examples : http://boinc.berkeley.edu/download.phphttp://boinc.berkeley.edu/download.php

P2P DirectoryP2P Directory

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Client/Server Networks

• Worldwide router growth

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Trace a route - Visual Route

• You can see how many routers are between you and any other computer you can name or know the IP address for.

•

• Visual Route

• Try a far away website server such as www.imu.edu.cn

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Topology

• Network topology - refers to the geometric arrangement of the actual physical organization of the computers and other network devices in a network– Bus topology– Star topology– Ring topology– Hybrid topology– Wireless

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Topology

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Videos

• How a Computer Network Works

• Bus Topology

• Star Topology

• Ring Topology

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What’s a protocol?

a human protocol and a computer network protocol:

Hi

Hi

Got thetime?

2:00

TCP/IP connection req

TCP/IP connectionresponse

Get http://www.stfx.ca/schedule

<file>time

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Protocols

• Protocol - a standard that specifies the format of data as well as the rules to be followed during transmission.

• For two devices on a network to successfully communicate, they must both understand the same protocols.

• Interoperability - the capability of two or more computer systems to share data and resources, even though they are made by different manufacturers

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• The most popular network protocols used are:

– Ethernet

– Transmission Control Protocol/Internet Protocol [TCP/IP]

Network Protocols

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Ethernet

• Ethernet - a physical and data layer technology for LAN networking

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Ethernet

• Ethernet is a local area technology with its protocol, with networks traditionally operating within a single building, connecting devices in close proximity.

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Ethernet Protocol

• Ethernet protocol standard

– Describes how messages are packaged– Determines how messages are processed– Personal computers usually support

10/100/1000 Ethernet • transmission rate of 10, 100, or 1000 Mbps

(megabits per second)

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Ethernet Card

Any computer as a member of a LAN must have a Ethernet card

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Ethernet Cable

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Transmission Control Protocol/Internet Protocol

• Transmission Control Protocol/Internet Protocol (TCP/IP) - provides the technical foundation for the public Internet as well as for large numbers of private network

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TCP/IP

TCP:

provides transport functions, ensuring, among other things, that the amount of

data received is the same as the amount transmitted.

IP:

provides the addressing and routing mechanism that acts as a postmaster

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TCP/IP Layers

• TCP/IP has 4 top-to-bottom layers:

– Application Layer– Transport Layer– Internet Protocol Layer– Network Layer

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TCP/IP standard for connectivity

• Transmission Control Protocol/Internet Protocol

• Allows any computer to communicate with any other (e.g., a PC and a Mac)

• Four layers to TCP/IP protocol

• Specifies:

– How sending computer to package data as messages

– How messages will be sent over the Internet

– How receiving computer will reassemble message for processing

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TCP/IP applied on email

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Videos

• TCP/ IP animation

• Learning Network Protocols

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Internet Protocol (IP) Address

• Every node in a network has a unique numeric IP address

•Form: Four blocks of 3 digit numbers separated by dots

Example: 141.109.221.124 (STFX IP address)

•Each block ranges from 0 to 255.

•Total number of possible IP addresses:

256 X 256 X 256 X 256 = 4,294,967,296 unique values!

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Internet Domain Names

- Domain names are used because people have difficulty remembering IP numbers

Example:

www.stfx.ca is domain name for the IP

address:

http://141.109.221.124/

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ping

• How to test if a node is alive:

– ping command in DOS– Ping a URL– Ipconfig (DOS) for your own IP address

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TCP/IP Applications

• SMTP (Simple Mail Transfer Protocol)– Communication standard for sending and receiving emails

• FTP (File Transfer Protocol)– A communication standard to transfer files over the Internet

• Telnet (Telnet Protocol)– remote login to a another computer

• Internet Relay Chat (IRC Protocol)– Communication via chat

• Usenet (news Protocol)

• Web ( HTTP Protocol)

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What Is the Internet?• The Internet is a worldwide network of networks

that uses the client/server model of computing and based on TCP/IP protocol.

• Using the Internet, any computer can communicate with any other computer connected to the Internet throughout the world.

• The Internet has no central management & no owners

• Major Internet capabilities include e-mail, Usenet, chatting and instant messaging, Telnet, FTP, and the World Wide Web.

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Internet Technology

• Based on client/server technology

• Client computers – access services and information available on server computers– Use software to access server computers

• Web browsers (Netscape, Internet Explorer)• Email software (Eudora, Outlook)

• Server Computers– They are programs that provide documents to requesting

browsers. They are slave programs.– Provide responses to browser requests, either existing

documents or dynamically built documents

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The Browser (client) and The Server

• The original static model of Web Serving:

• The HyperText Transfer Protocol (HTTP) enables web pages to be requested and transferred between the browser and server

WebBrowser

WebServer

HTTP Request

Web Page

FileSystem

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Internet network architecture

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The Internet connectivity

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Voice over IP (VoIP)

• Voice over IP (VoIP) - uses TCP/IP technology to transmit voice calls over long-distance telephone lines

• VoIP transmits over 10 percent of all phone calls in the United States and this number is growing exponentially.

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Internet Telephony (VoIP)

• The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and compression/translation of the signal into Internet protocol (IP) packets for transmission over the Internet; the process is reversed at the receiving end

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Cisco IP Phone

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Skype

• VoIP application

• call forwarding

• block unwanted calls

• conference calling

• Instant msg

• Video calls

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Media

• Network transmission media - refers to the various types of media used to carry the signal between computers

– Wire media (guided)– Wireless media (unguided)

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Wire Media

• Wire media - transmission material manufactured so that signals will be confined to a narrow path and will behave predictably

• Three most commonly used types include: 1. Twisted-pair wiring

2. Coaxial cable

3. Fiber optic (or optical fiber)

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Wire Media

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Twisted-pair cable

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Coaxial Cable

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Fiber Optic

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Wireless Media

• Wireless media - natural parts of the Earth’s environment that can be used as physical paths to carry electrical signals

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E-Business Network

• Virtual private network (VPN) - a way to use the public telecommunication infrastructure (e.g., Internet) to provide secure access to an organization’s network

• Valued-added network (VAN) - a private network, provided by a third party, for exchanging information through a high capacity connection

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What is a VPN and why is it important?

• Virtual Private Network (VPN)– Uses public Internet to create appearance of

private point-to-point connection

– Client and server have point-to-point connection called a tunnel

– Secure, encrypted communications

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WAN Using VPN