Transcript Diapositiva 1

C7- Telecommunications, The Internet, and Wireless Technology
Telecommunications and Networking in
Today’s Business World
• A networking and communications revolution led
by Internet-based technologies
• Convergence of telephone and computer
networks
• Voice and data communication networks are
becoming faster, more portable, and less
expensive
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What is a computer network?
• Consists of two or more
connected computers
• Each computer contains
a network interface card
(NIC)
• The connection medium
– telephone wire, coaxial
cable, or radio signal in the
case of cell phone and
wireless local area
networks
• Network Operating
System (NOS)
– Routes and manages
communications on the
network and coordinates
network resources
• Dedicated server
computer
• Hubs
• Routers
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What is a computer network? ...
• Most networks contain a switch or a hub acting
as a connection point between the computers
– Hubs are simple devices that send packets of data to
all other connected devices
– Switches can filter and forward data to specified
locations with some intelligence
• Routers send packets of data though different
networks
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A Simple Network
Where is the
• Client computers
• Network operating system
• Server computer
• Cable (wiring)
• Network interface cards (NICs)
• Switches, and a router.
Figure 7-1
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Corporate Network
Infrastructure
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Client/Server Computing
• A distributed processing model
– some processing power is located
within small, inexpensive client
computers
– The clients are linked to one another
• The network is controlled by a
network server computer
– The server sets the rules of
communication for the network
– provides every client with an
address so others can find it on the
network
Key Digital
Network
Technologies
Client/Server
Computing
Packet
Switching
TCP/IP and
Connectivity
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Packet Switching
Key Digital Network Technologies
1. Message broken down to packets
2. Sent through different communication path
3. Reassembled at destination
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TCP/IP Protocol
Key Digital Network Technologies
• TCP/IP uses a suite of
protocols:
– TCP: Transmission Control
Protocol – establish a
connection
– IP: Internet Protocol –
handles delivery of packets
• set of rules governing
transmission of
information- used by and
all Internet devices
• TCP/IP provides for
breaking up digital
messages into
packets, routing them
to the proper
addresses, and then
reassembling them
into coherent
messages
Communications Networks
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The Internet
• It is a network
– Links hundreds of thousands of individual networks all
over the world
– Composed of computers and other devices that are
logically linked together by a unique address space
based on Protocol
– Where devices are able to support communications
using TCP/IP
– That provides high-level services layered on a
communication and network infrastructure
• Most homes connect to the Internet by
subscribing to an Internet Service Provider (ISP)
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Internet Services
• E-mail: Person-to-person
messaging; document
sharing
• Usenet newsgroups:
Discussion groups on
electronic bulletin boards
• Chatting and instant
messaging: Interactive
conversations
• Telnet: Logging on to one
computer system and
doing work on another
• FTP: Transferring files
from computer to
computer
• World Wide Web:
Retrieving, formatting,
and displaying
information (text, audio,
video, graphics) using
hypertext links
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Internet Features
Hypertext
Searching information
• Web pages based on a
standard Hypertext
Markup Language
(HTML)
• Web browsers request
web pages stored on an
Internet host server using
Hypertext Transfer
Protocol (HTTP)
• The address of a web
page is its Uniform
Resource Locator (URL)
• Search engines
• Intelligent agents
shopping bots
• Web logs (blogs)
• Semantic web
Technologies And Tools
For Communication And E-business
Intranets and Extranets
Virtual Private Networks (VPN)
• Intranet:
• A private network
configured within a public
network to take
advantage of economies
of scale and facilities of
larger networks
• Secure connection
between two points on
• Less expensive, more
flexible, greater
bandwidth than non-IP
networks
– an internal organizational
network that provides
access to data across the
enterprise
– Protected from public visits
by firewalls
• Extranet:
– Authorized visitors
(vendors, customers) are
given limited access to an
internal intranet
The Wireless Revolution
• Mobile phones are now platforms for delivering
digital data, used for recording and downloading
photos, video and music, Internet access, and
transmitting payments
• An array of technologies provides high-speed
wireless access to for PCs and other wireless
handheld devices and cell phones
• Businesses increasingly use wireless to cut
costs, increase flexibility, and create new
products and services
Wireless Transmission Media
and Devices
• All wireless media rely on
various parts of the
electromagnetic
spectrum
• Microwave systems
transmit high-frequency
radio signals through the
atmosphere
• Communication satellites
are used for
geographically dispersed
organizations
• Blackberry: email
handheld
• PDAs: small handheld
computers
– electronic scheduler
• Cellphones: use radio
waves to communicate
with towers in cells
– message passed from cell
to cell
• Smartphones: can save
information, access
Internet
Mobile Wireless Standards for
Web Access
• Wireless Application Protocol (WAP): Uses
Wireless Markup Language (WML) and
microbrowsers
• Bluetooth
– Creates small Personal Area Networks (PAN)
– Can link up to 8 devices in 10-m area
– Low power requirements
Wi-Fi
• Three standards:
802.11a, 802.11b,
802.11g
• Infrastructure mode:
Devices use access
point to communicate
with wired network
• Ad-hoc mode (peerto-peer): Wireless
devices communicate
directly with each
other
• Benefits of Wi-Fi
– Low-cost to provide
Internet access to
conference rooms,
workstations
– Allows hot-spots in
public areas such as
university campuses,
airports …
• Challenges
– Security
– Susceptibility to
interference
An 802.11 Wireless LAN
How RFID Works
Wireless in Heath Care
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Electronic Medical Record (EMR) retrieval
Wireless note taking for patient charts
Lab test results
Prescription generation
Medical databases
Wireless Technology In
The Enterprise
• Pervasive Computing
– Wireless technologies are pushing computing into
every facet of life, including cars, homes, office
buildings, tools and factories; providing connections
anywhere and anytime
• Wireless sensor networks (WSNs)
– Networks of interconnected wireless devices that are
embedded into the physical environment to provide
measurements of many points over large spaces