Telecommunication, Internet, and E-Commerce - PowerPoint PPT Presentation


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Telecommunication, Internet, and E-Commerce


Telecommunication, Internet, and E-Commerce Communication Channel Media Bandwidth: The speed at which information is transmitted over a communication medium. – PowerPoint PPT presentation

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Title: Telecommunication, Internet, and E-Commerce

Telecommunication, Internet, and E-Commerce
Communication Channel Media
  • Bandwidth The speed at which information is
    transmitted over a communication medium. It is
    measured by the bits of data transmitted per
  • Wire cables
  • twisted-pair (voiceband) 2MBPS
  • coaxial gt 100 MBPS
  • Broadband cable
  • fiber-optic 30 GBPS
  • Broadband over Power Lines (BPL)
  • Wireless channel
  • microwave (land-based, satellite-based)100 MBPS
  • Satellite
  • infrared 4 MBPS

Digital Subscriber Line (DSL)
  • DSL offers high-speed data access over the single
    pair of the ordinary copper lines used with basic
    telephone service.
  • The Last Mile
  • The last mile is the final leg of delivering
    connectivity from a communications provider to a

Types of Networks
  • Local Area Network
  • Within office
  • Cable or Wireless
  • peer-to-peer all PCs are equal
  • client/server network
  • Wireless local area network (WLAN)
  • Metropolitan Area Network
  • City area
  • Fiber optic cable
  • Wide Area Network

Wireless local area network (WLAN)
  • WI-FI Wireless local area network (WLAN) based
    on the IEEE802.11 specifications.
  • Hotspot A person with a Wi-Fi device, such as a
    computer, cell telephone, or personal digital
    assistant (PDA) can connect to the Internet when
    in proximity of an Access Point. The region
    covered by one or several access points is called
    a hotspot.

Introduction to Internet
  • A network of networks that connects computers
    across the world.
  • It is growing rapidly
  • Host computers
  • Users
  • Information
  • It is a network that follows the TCP/IP protocol
    (packet switch network).

Internet protocol
  • Transmission Control Protocol handles
    communications between applications.
  • A message is divided into pieces called packets.
  • Packets are numbered and may be transmitted by
    different routes.
  • Internet Protocol handles communications
    between network addresses.
  • A computer on the internet is assigned an unique
    address, IP address, which consists of 4 numbers
    (each number is less than 256) separated by
    period. Exanple,

Domain Name System
  • Domain
  • .com, .net, .org,, .int, .gov
  • .info, .biz, .name, .etc.
  • Domain names are the familiar, easy-to-remember
    names for computers on the Internet.
  • Each domain name correlates to assigned IP

Organizations that Regulate Internet
  • ICANN (Internet Corporation for Assigned Names
    and Numbers)have responsibilities in Internet
    Protocol addresses and domain names.
  • Domain name registry

Examples of Internet Services
  • World Wide Web
  • A system of interlinked, hypertext documents that
    runs over the Internet.
  • Web publishing and browsing
  • Email
  • FTP - File Transfer
  • Telnet

World Wide Web
  • A service on the Internet that links information
    so that the user can easily go from one piece of
    information to another, related piece.
  • Web pageHypertext/Hypermedia
  • a document that contains hyperlink (link) to
    another hypertext.
  • Uniform Resource Locator (URL)
  • http//Web site/Directory/Document

  • It is a corporate network that functions with
    Internet technologies, such as browsers, using
    Internet protocols.
  • Major applications
  • Corporate/department/individual web pages
  • Database access
  • Interactive communication
  • Document distribution

Applications of Intranets
  • It is a network that links the intranets of
    business partners over the Internet by Virtual
    Private Network.
  • Virtual Private Network
  • A secure network that uses the Internet as its
    main backbone network to connect the intranets of
    a companys different locations, or establish
    extranet links between business partners.
  • Improved communications between business partners

  • Buying and selling, and marketing and servicing
    of products and services, and information via
    computer networks.

E-Commerce Models
  • B2C Storefront model
  • E-tailing (electronic retailing)
  • Shopping cart, on-line shopping mall
  • B2B
  • Electronic Data Interchange (EDI)
  • Electronic Exchange An electronic forum where
    manufacturers, suppliers, and competitors buy and
    sell goods.
  • Example WorldWide Retail Exchange (WWRE)
  • C2C
  • Auction model e-Bay
  • Moble Commerce (M-commerce)
  • Wireless Application Protocol (WAP)
  • PDA, Cell phone,

Electronic Payment Systems
  • Authentication technologies
  • Digital certificate
  • Electronic cash
  • Electronic walletcontains
  • electronic cash or credit card info
  • Owner identification
  • Credit/debit/smart card

Internet Security
  • Authenticity Is the sender of a message who they
    claim to be?
  • Privacy Are the contents of a message secret
    and only known to the sender and receiver?
  • Integrity Have the contents of a message been
    modified during transmission?
  • Nonrepudiation Can the sender of a message deny
    that they actually sent the message?

Encryption (Cryptography)
  • Plain text the original message in
    human-readable form.
  • Ciphertextthe encrypted message
  • Encryption algorithm the mathematical formula
    used to encrypt the plain text.
  • Key the secret key used to encrypt and decrypt a

Encryption Example
  • Digits 0-9,
  • Encryptor
  • Replace each digit by Mod(Digit Key, 10)
  • Keys value is from 0 to 9
  • If Key 7, then
  • 0 -gt 7, 1-gt8, 2-gt9, 3-gt0, 4-gt1, 5-gt2
  • Decryptor
  • Replace ach digit byMod(Digit (10-Key), 10)
  • If key7, then
  • 7-gt0, 8-gt1, 9-gt2, 0-gt3

Encryption Algorithms
  • Private key encryption
  • Public key encryption
  • Digital signature
  • Digital certificate

Private Key Encryption
  • The same key is used by a sender (for encryption)
    and a receiver (for decryption)
  • The key must be transmitted to the receiver.
  • Example
  • DES (Data Encryption Standard) algorithm with
    64-bit key

Public Key Encryption
  • Uses two different keys a public and a private
  • Receivers public key must be delivered in
  • Sender uses receivers public key to encrypt the
    message and receiver uses private key to decrypt
    the message (Sender can be sure the receiver is
    the true receiver)
  • Example
  • RSA (Rivest, Shamir, and Adelman) algorithm with
    512-bit to 1024-bit key.
  • Note Although the two keys are mathematically
    related, deriving one from the other is
    computationally infeasible.

Digital Signature
  • It is used for the authentication and
    nonrepudiation of senders by applying public key
    encryption in reverse.
  • To make a digital signature, a sender encrypts a
    message with his/her private key, and any
    receivers with senders public key can read it.

  • A certificate is an identification issued by a
    trusted third-party certificate authority (CA).
  • A certificate contains records such as a serial
    number, users name, owners public key, name of
    CA, etc.
  • Example of CA VeriSign, U.S. Postal Service.

Transaction Certificate
  • A transaction certificate attests to some fact
    about the conduct of a transaction that can be
    used to prevent repudiation.
  • SSL (Secure Socket Layer) Protocol developed by
  • SET (Secure Electronic Transaction) Protocol
    developed by Visa and MasterCard.

  • Designed to hold information about a user.
  • Created by a web site and saved on the visitors
  • It contains
  • Web site that sets the cookie.
  • One or more pieces of data.
  • Expiration date for this cookie.
  • Cookies directory
  • Browser sends cookie with the URL when you visit
    the site that issued the cookie.