Matakuliah
Tahun
Versi
: M0284/Teknologi & Infrastruktur E-Business
: 2005
: <<versi/revisi>>
Pertemuan 4
Networking Fundamentals
1
Learning Objectives
• Identify Different Communication Media
• Describe digital transmission services
2
Overview
• Communication Media
• Telephone networks
• Digital Transmission Services
3
Transmission Media
• Through which signals flow
• Four characteristics
– Cost
– Transmission capacity
– Length of media before regeneration
– Protection against interference
4
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
5
Media Copper wire
6
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
7
Media Coaxial
8
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
9
Media Fiber Optic
10
Media Wireless
• Two configurations
• Directional
– direct broadcast satellite, Microwave transmission: Satellite and
terrestrial
• Omni-directional
– AM,FM TV broadcast, Cellular phone
11
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
12
Media Satellites (GEO)
13
Satellite Point-to-Point
14
Satellite VSAT
Very small aperture terminal is popular for business applications
15
Telephone Network
16
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)
17
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
18
Telephone: Digital Transmission
• T-1 Carrier system
• SONET/ OC (Synchronous optical
network/ optical carrier system)
• ISDN (Integrated services digital network)
19
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
20
Digital Transmission T-1
21