Computer Networks Transmission Media
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Transcript of Computer Networks Transmission Media
Telecommunications and Computer Networks
Agenda
• Purpose of Computer Networking
• Transmission Media
Communications
Communications
The analog signal(audible)
is sent throughtelephone lines.
MODEM MODEM 011010001011010001
Digital signal Digital signal
This modem convertsdigital to analog.
This modem convertsanalog to digital.
Computer Networking
• Interconnected collection of computers that share data, memory and other valuable resources.
• A computer network consists of communication media, devices and software needed to connect two or more computer systems and/or devices.
• Networks can be used to share hardware, programs and databases across the organization.
Purpose of networking
• Data communication
• Simultaneous Access
• Resource sharing
• Reliability
• Scalability
• Save money
The Uses of a Network - Simultaneous Access
• In organizations, many people may need to use the same data or programs
• Shared data and programs can be stored on a central network server
• Managers may assign access rights to users.
Read/writeRead/writeRead/writeRead/writeRead/writeRead only
• It is cost-effective to connect a device to a network so users can share it.
• Users can send multiple documents (called print jobs) to a networked printer at the same time.
• E-Mail• Teleconferencing• Video Conferencing
The Uses of a Network -Shared Peripheral Devices
The Uses of a Network - Personal Communication
1 2 3 4
Email service – process flow
Transmission Media
Types of Media
• Twisted-Pair
• Coaxial Cable
• Fiber-Optic Cable
• Microwave Transmission
• Satellite Transmission
Twisted-Pair
Twisted-Pair Wire Cable
Advantages
-least expensive
-widely available
-moderate capacity
-easy to install
-transfer 10-100Mbps
Disadvantages
-Slow(low bandwidth), Easily tapped
Coaxial Cable
Coaxial Cable
• -moderately expensive• -higher capacity• -bulky• --transfers 1-2 Gbps• -usually used to carry TV signals
Fiber Optic Cable
Fiber Optic Cable…
• -very expensive• -high capacity• -uses light• -travels long distance
without attenuation (several Gbps for about 100-200 Km)
Microwave Transmission
• -Expensive• -Requires no cabling• -best for high volume and long distance• -limited to line of sight• -waves travel in a straight line and
narrowly focused in a parabolic antennae• -can’t penetrate solid objects
Microwave Transmission
Satellite Transmission
Technological Updatesin Information Systems
Emerging Technologies
• WiFi
• WiMax
• VOIP
• GPS
• RFID
WiFi
• Wireless Fidelity = wireless LAN
• Wireless Connection to access a Network
• Wireless LAN
• Standard for transmitting information in the form of radio waves over distances up to about 100 - 300 feet
WiMax
• Worldwide Interoperability Microwave Access = Metro based broadband wireless access
• Longer distance coverage (~50 km)
• Connecting geographically remote areas
VOIP
• Voice Over Internet Protocol
• VOIP Phones are connected to the internet using n/w cables or WiFi
• Preferred over normal cabled telephone
• Interactive user interface
• Easy connectivity
VOIP
• Cost Reduction
• Quality
• Parallel calls using same connection
• No limitation on location
GPS
• Global Positioning System
• Satellite based tracking
• Used for navigation
• Applications:– Fleet Management– Logistics– Asset tracking
RFID
• Radio Frequency Identification• Transmitting signal over Radio Wave from an
object connected to RFID device to the reader
• Objective is to keep track• Applications :
– Inventory Management– Retail Store– Logistics
RFID Applications