MODULE

Email and Messaging

1

Email

• Messages exchanged among Internet subscribers

• Vary from a simple text based messages to one that carries different attachments– Word, PowerPoint documents– Any computer file– Video and audio clippings etc.

Messaging

• Email expanded to include a number of other functions and services

• Document sharing and collaboration • Whiteboard applications• Scheduling of group activities• Etc.

Collaboration and Sharing

Internet

User 1

User 2

Documentfor

Sharing orCollaboration

Sharing: Both users can see the document but only one can make changes

Collaboration: Both users can see and also make changes to the document

NetMeeting

Implementation Of Messaging

Server

Client 1 Client 2

Lotus Domino server, Microsoft Exchange Server

Internet

Internet serviceProvider

WWW Services

Major Messaging Products

• Microsoft Exchange Server– Outlook and Outlook Express Clients

• Lotus Domino Server– cc:Mail– Lotus Notes (Client)

• Netscape ???

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Voice Over IP and Internet Telephony

7

Voice Over IP and Internet Telephony Defined

• The use of the internet to transmit voice in real-time– Transmission of digitized voice using

the Internet Protocol

• Internet Telephony is an example– Usage of the Internet to transmit

telephone calls

Internet Telephony Defined

• Using the Internet (TCP/IP) for largely the telephone related applications– Termination of voice traffic

Voice over IP Prospects and Challenges

• Voice transmission over the Internet has been identified as one of the largest growth areas– Companies will in the future use the

Internet extensively for voice communications

• Current IP is not well suited for voice transmission– Latency being the biggest drawback

• Bandwidth restrictions also hamper voice transmission

• IP is being improved to carry voice

Internet Telephony• A growing market • Further information

– http://www.internettelephony.com/

• Current Products (???)– Net meeting (Microsoft)– ICQ– Cooltalk (Netscape) etc.

• Long-term focus is on regularly using the Internet as a viable alternative to the Plain Old Telephone Service (POTS)

• H.323 is the prominent standard for Internet telephony

Sample Telephony Applications

Computer-to-Computer Calling • Computer-to-Phone Calling:

– Requires ITSP service in addition to regular ISP service

– www.dialpad.com

• Phone-to-phone– Using TCP/IP

• Live Motion Video– Video Conferencing

• Whiteboarding: – Share and edit photos, documents and drawings

with others in real time.

• Voice Mail: – Record compressed voice files and sending them

as attachments.

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Virtual Private Networks (VPN)

13

VPN Defined

• A private network that uses the public network infrastructure

• A secured web of tunnels that links various nodes to form the Virtual Private Network

Virtual Private Network

Public

VPN

VPN Implementation

Internet

Company’s Intranet

Point-to-Point Tunneling Protocol

(PPTP)Fire Wall

VPN Past and Present

• Past– Based on PSTN (Public Switched

Telephone Network)

• Present– Based on next generation public

network technologies

Source: VPNWorx, VPN Quick Reference Guide

Base Technologies for VPN

• Carrier IP• PPTP• Frame Relay• ATM

Areas of Applications

• All major business organizations that require a secured Extranet

MODULE

WAN and Access Technologies

20

WAN Scope

• Enterprise-wide• Metropolitan and National• Global• Underlying network infrastructure

for the Internet• Fastest growing network

– Growth is appreciable in the area of Virtual Private Network

The Early Days of Communications and

Computing • Telecommunication

– Centered on analog technology

• Data communication needs– Centered around digital technology

• Digital to analog interface– For long distance communications

Long-distance Communications

Digital Digital

Modulation

Plain Old Telephone Service (POTS)

Analog

Interface

Initial WANs

• Introduced to overcome the limitations of general purpose analog telephone lines used– Better conditioned lines such as leased lines were

used

• Driven by a collection of computers for routing the data traffic from source to destination

• Arpanet was the first WAN to be created• X.25 was the initial communication

technology used– X.21 was used in Europe

Basic Components of the WAN

Leased lines

Computers/Routing algorithms

Routing devices

X.25 Driven

Present Status of WANs

• Information is carried in digitized form in many segments of the WAN

• Digital communication lines– Over copper wire– Over fiber-optics

• Telecommunications and computer communications are merging in terms of deploying digital technology

WANs: Present and Future

• Move towards digital technology• Technologies

– Frame Relay– ATM

• Point-to-point digital communication will become widely used in the future

• The WAN of the future will be designed to meet with the increasing bandwidth demands of the Internet– Internet2

ATM operating at severalhundred Mbps

Internet2: The WAN of the Future

Ramp

BusinessComputer System

ATM Switches

High speed digital lines

28

Possible Convergence Digital Technology

• Networks– Local– Enterprise– Wide area– Global

ATM

Point-to-point ATM connection is possible probably under a single technology

ATM Promise

Server

Client 1 Client 2

25 Mbps

ISP100 Mbps

Internet Backbone

1 Gbps

300 Mbps

Challeng Posed by Gigabit Ethernet to ATM

1 Gbps(Gigabit)

100 Mbps(Fast)

10 Mbps

1 Mbps(Past)

Ethernet EvolutionClient 2

10 Mbps/100 Mbps/

1 GbpsServerISP

Client 1

Hub

Wide Area Network Technologies

WANTechnologies:

X.25 (old)FDDI

Frame RelayATM

LosAngeles

Seattle New York

Florida

Front-end Access Technologies

• ISDN• xDSL • Cable modem• Direct satellite access

• ADSL is an example of xDSL

Access Speeds

• Fastest speed of an analog modem is around 56K bps

• Newer technologies operate at faster speeds

• Newer technologies have made a significant contribution in increasing the speed of communication

Digital Internet Technologies Summarized

FDDIFrame Relay

ATM

Cable

Mod

em

Direct

Satell

ite A

cces

s

xDSL

ISDN

35

MODULE

Audio and Video Streaming

36

Audio and Video Streaming

• Deliver continuous audio and video streams over a low bandwidth connection

• Packet switching networks do no guarantee real-time and continuous delivery of data packets

• Streaming involves compression and decompression (CODEC)

Application Areas

• Dissemination of multimedia information on the web

• Training and education• Etc.

Streaming Examples

Streaming Software

Audio (wav)Video (AVI)

Real FormatRM, RMA, RT,

RP etc.

Windows FormatASF etc.

39

Hosting of Streamed Media

Streaming Server(Real Server orWindows Media

Server)

Internet

Streaming at 28.8, 56, 128 etc. Kbps40

Method of Delivery

• Unicasting• Multicasting• Broadcasting

Major Streaming Technologies

• Real• Microsoft Windows Media

Technologies

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Video Conferencing

43

Video Conferencing

• The exchanging of audio and video information while engaged in conferencing

Major Types of Video Conferencing

• Dedicated video conferencing– Telecommunication lines are used

solely for the purpose of setting up a video conferencing facility

• Desktop video conferencing– Video conferencing conducted from a

computer connected to the Internet

Video Conferencing Standard

• H.232 Series of standards

Sample Desktop Video Conferencing Products

• CU-SeeMee• Intel ProShare• Microsoft NetMeeting• PictureTel

Keywords

• Intranet, Extranet, Internet• VPN, PPTP• Real Media and Windows Media• Network appliance and Internet

Appliance• Sharing, Collaboration • Messaging Server and Messaging

Client

Keywords

• SMTP, POP3, IMAP• VoIP, H.323, IPv6• X.25, ATM, Frame Relay, FDDI• T1, T3, OC1, OC2 • ISDN, xDSL, Cable Modem, Satellite• Unicasting, Multicasting and

Broadcasting

Microcomputer-based Distributed Architecture

Fiber Optic Backbone(FDDI)

Mainframe/Minicomputer

Systems

Bus LAN

RingLAN

WAN Gateway(TCP/IP)

ModemGateway

External Digital/Analog Lines

Microcomputers

• Widespread usage– Serious business computer

• Dramatic increase in power– Comparable to mainframes of the past

• Declining cost– Affordable to use in all levels of business

• Communication device– Access services and resources on the

Internet

Connectivity

• Computers are increasingly being viewed as resources in a network and not simply as stand-alone units any more

• LANs, Departmental networks, Enterprise networks, WANs etc. are deployed widely in business

Downsizing: Path of Evolution

CentralizedMainframe

DistributedNetwork

Client-ServerArchitecture

Thin-clientconcept

More power to the user

Better management of shared dataReduced cost of ownership

Client-Server Computing Architecture

• Centralized data– Control and management

• Distributed processing– Processing using client-tools

• Mainframe advantage• Microcomputer flexibility

Preview of Client-Server Computing

Back-end data storage and retrieval.

Front-end interface and data manipulation tools.

Server

Clients

55

A Preview of Thin-Client Concept

Powerful Server

Thin Clients

Limited front-end processing and storage

Extensive back-end data storage, retrieval and

Processing

Digitization Of Telecom Network

• Mode (ATM)

Front-end Access Technologies

• ISDN• xDSL • Cable modem• Direct satellite access

• ADSL is an example of xDSL

Access Speeds

• Fastest speed of an analog modem is around 56K bps

• Newer technologies operate at faster speeds– In the Mbps region

• Newer technologies have made a significant contribution in increasing the speed of communication