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Pertemuan 4 Networking Fundamentals

Matakuliah : M0284/Teknologi & Infrastruktur E-Business

Tahun : 2005

Versi : <<versi/revisi>>

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Learning Objectives

• Identify Different Communication Media• Describe digital transmission services

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Overview

• Communication Media

• Telephone networks

• Digital Transmission Services

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Transmission Media

• Through which signals flow

• Four characteristics– Cost– Transmission capacity– Length of media before regeneration– Protection against interference

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Media Twisted Pair Copper Wire

• Twisted pair copper wiring

• Used in telephone lines connecting our homes– low capacity 3kilobits/second

• Used in local area networks. – Cat 5 cables up to 100 million bits/second

• Low cost, low capacity, frequent regeneration and subject to interference

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Media Copper wire

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Media Coaxial Cable

• Coaxial Cable

• Used in local area networks and in cable television transmission

• Used for high speed Internet connection provided by cable t.v. companies

• Medium cost, 100 million bits per second, moderate protection against second

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Media Coaxial

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Media Fiber Optic

• Fiber Optic Laser lights on and off and in different colors

• High as 10 gigabits per second

• Immune to electrical interference

• High cost

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Media Fiber Optic

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Media Wireless

• Two configurations

• Directional – direct broadcast satellite, Microwave transmission: Satellite and

terrestrial

• Omni-directional – AM,FM TV broadcast, Cellular phone

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Media Satellite

• Geo-synchronous orbit

• Low earth orbit within 1000 miles from Earth. Few hundred satellites to cover the planet. Iridium, Teledisc, Globalstar

• Medium Earth orbit within 6000 miles from Earth. More than 10 satellites to cover the planet

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Media Satellites (GEO)

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Satellite Point-to-Point

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Satellite VSAT

Very small aperture terminal is popular for business applications

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Telephone Network

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Telephone Network

• A hierarchical network system• Connection from home to Central Office

– CO: Level 5 switch. Usually with low capacity copper wires

• Level 4 switch (toll office) – Calls that are billed pass through a toll office. Lines

from here on are high capacity fiber optics

• Level 3 switch (primary center)• Level 2 switch (sectional center)• Level 1 switch (regional center)

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Networks: Switched and Packet

• Telephone network is switched specific connection between two ends maintained throughout the conversation. Uses PCM to translate analog signals to digital. Uses TDM and FDM to multiplex signals over trunk lines

• Packet Switching Signals travel as independent packets as in US mail. Different packets (like cars) share the same line. No specific connection maintained between 2 ends. Basis of Internet and World Wide Web system

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Telephone: Digital Transmission

• T-1 Carrier system

• SONET/ OC (Synchronous optical network/ optical carrier system)

• ISDN (Integrated services digital network)

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Digital Transmission: T series

• Developed to send digital signals over old copper wires.

• A hierarchy of signals

• T-1 is 1.544 mbps. Connect offices to Central Offices with high capacity lines

• T-3 lines carry 28 T-1 lines 44.726 mbps

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Digital Transmission T-1