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![Page 1: MODULE Email and Messaging 1. Email Messages exchanged among Internet subscribers Vary from a simple text based messages to one that carries different.](https://reader036.fdocuments.in/reader036/viewer/2022062801/56649e1a5503460f94b085fb/html5/thumbnails/1.jpg)
MODULE
Email and Messaging
1
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• 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.
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Messaging
• Email expanded to include a number of other functions and services
• Document sharing and collaboration • Whiteboard applications• Scheduling of group activities• Etc.
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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
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Implementation Of Messaging
Server
Client 1 Client 2
Lotus Domino server, Microsoft Exchange Server
Internet
Internet serviceProvider
WWW Services
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Major Messaging Products
• Microsoft Exchange Server– Outlook and Outlook Express Clients
• Lotus Domino Server– cc:Mail– Lotus Notes (Client)
• Netscape ???
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MODULE
Voice Over IP and Internet Telephony
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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
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Internet Telephony Defined
• Using the Internet (TCP/IP) for largely the telephone related applications– Termination of voice traffic
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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
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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
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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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MODULE
Virtual Private Networks (VPN)
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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
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Virtual Private Network
Public
VPN
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VPN Implementation
Internet
Company’s Intranet
Point-to-Point Tunneling Protocol
(PPTP)Fire Wall
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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
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Base Technologies for VPN
• Carrier IP• PPTP• Frame Relay• ATM
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Areas of Applications
• All major business organizations that require a secured Extranet
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MODULE
WAN and Access Technologies
20
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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
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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
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Long-distance Communications
Digital Digital
Modulation
Plain Old Telephone Service (POTS)
Analog
Interface
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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
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Basic Components of the WAN
Leased lines
Computers/Routing algorithms
Routing devices
X.25 Driven
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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
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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
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ATM operating at severalhundred Mbps
Internet2: The WAN of the Future
Ramp
BusinessComputer System
ATM Switches
High speed digital lines
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Possible Convergence Digital Technology
• Networks– Local– Enterprise– Wide area– Global
ATM
Point-to-point ATM connection is possible probably under a single technology
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ATM Promise
Server
Client 1 Client 2
25 Mbps
ISP100 Mbps
Internet Backbone
1 Gbps
300 Mbps
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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
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Wide Area Network Technologies
WANTechnologies:
X.25 (old)FDDI
Frame RelayATM
LosAngeles
Seattle New York
Florida
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Front-end Access Technologies
• ISDN• xDSL • Cable modem• Direct satellite access
• ADSL is an example of xDSL
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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
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Digital Internet Technologies Summarized
FDDIFrame Relay
ATM
Cable
Mod
em
Direct
Satell
ite A
cces
s
xDSL
ISDN
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MODULE
Audio and Video Streaming
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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)
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Application Areas
• Dissemination of multimedia information on the web
• Training and education• Etc.
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Streaming Examples
Streaming Software
Audio (wav)Video (AVI)
Real FormatRM, RMA, RT,
RP etc.
Windows FormatASF etc.
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Hosting of Streamed Media
Streaming Server(Real Server orWindows Media
Server)
Internet
Streaming at 28.8, 56, 128 etc. Kbps40
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Method of Delivery
• Unicasting• Multicasting• Broadcasting
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Major Streaming Technologies
• Real• Microsoft Windows Media
Technologies
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MODULE
Video Conferencing
43
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Video Conferencing
• The exchanging of audio and video information while engaged in conferencing
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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
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Video Conferencing Standard
• H.232 Series of standards
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Sample Desktop Video Conferencing Products
• CU-SeeMee• Intel ProShare• Microsoft NetMeeting• PictureTel
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Keywords
• Intranet, Extranet, Internet• VPN, PPTP• Real Media and Windows Media• Network appliance and Internet
Appliance• Sharing, Collaboration • Messaging Server and Messaging
Client
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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
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Microcomputer-based Distributed Architecture
Fiber Optic Backbone(FDDI)
Mainframe/Minicomputer
Systems
Bus LAN
RingLAN
WAN Gateway(TCP/IP)
ModemGateway
External Digital/Analog Lines
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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
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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
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Downsizing: Path of Evolution
CentralizedMainframe
DistributedNetwork
Client-ServerArchitecture
Thin-clientconcept
More power to the user
Better management of shared dataReduced cost of ownership
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Client-Server Computing Architecture
• Centralized data– Control and management
• Distributed processing– Processing using client-tools
• Mainframe advantage• Microcomputer flexibility
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Preview of Client-Server Computing
Back-end data storage and retrieval.
Front-end interface and data manipulation tools.
Server
Clients
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A Preview of Thin-Client Concept
Powerful Server
Thin Clients
Limited front-end processing and storage
Extensive back-end data storage, retrieval and
Processing
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Digitization Of Telecom Network
• Mode (ATM)
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Front-end Access Technologies
• ISDN• xDSL • Cable modem• Direct satellite access
• ADSL is an example of xDSL
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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