Transcript Chapter 1

Chapter 1
Lecture 2
Review
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Topology Types
Name the Physical Topologies and their
logical topology
Peer to peer network
Client/server network
LAN
WAN
CSMA/CD
IEEE
Topics
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Wireless Topology
Standards
Standard Elements
802.3
802.5
802.11
ANSI X3T9.5
Wireless Topology
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Requires a WAP (wireless access point)
and a Wireless NIC
Provides easy, flexible access
No cables
Slower than wired network
Security is an issue
Standards
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Agreed upon rules for how the network
operates
IEEE – Institute of Electrical and
Electronics Engineers
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International body that developed the 802
standards
ANSI – American National Standard
Institute
Standards Elements
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Access
Speed
Media
Topologies
802.3
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Ethernet standard
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Access method: CSMA/CD (carrier sense multiple
access with collision detection)
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Contention-based access
All nodes have equal access
Speed: 10 Mbps
Media: Twisted pair cable, thin coaxial cable,
thick coaxial cable, or fiber optic
Physical Topologies: Star, bus
Logical Topology: bus
802.3u
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Fast Ethernet standard
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Access method: CSMA/CD (carrier sense
multiple access with collision detection)
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Contention-based access
All nodes have equal access
Speed: 100 Mbps
Media: Twisted pair cable, fiber optic cable
Physical Topologies: Star, bus
Logical Topology: bus
802.3z
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Gigabit Ethernet standard
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Access method: CSMA/CD (carrier sense
multiple access with collision detection)
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Contention-based access
All nodes have equal access
Speed: 1000 Mbps (1 Gbps)
Media: Fiber Optic, twisted pair cable
Physical Topologies: Star, bus
Logical Topology: bus
802.5
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Token Ring (second most popular)
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Not contention-based
A node must wait for a token to be able to
transmit
Lack of collisions (good for applications that
require constant communication such as
videoconferencing)
Reduced speed because of overhead created by
token process
Requires expensive hardware and software
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MSAU – multistation access unit (hub)
802.5 cont’d
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Access: Token-passing
Speed: 4 Mbps or 16 Mbps
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ALL devices in the network must be set to
the same speed
Media: Twisted pair
Physical Topology: star, ring
Logical Topology: ring
802.11b
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Access: CSMA/CA
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Carrier Sense Multiple Access with Collision
Avoidance
Speed: 11 Mbps, 5.5 Mbps, 2 Mbps,
1 Mbps
Media: Radio frequency
Physical Topology: Wireless
802.11g
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Access: CSMA/CA
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Carrier Sense Multiple Access with Collision
Avoidance
Speed: 54 Mbps
Media: Radio frequency
Physical Topology: Wireless
802.12
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100VG-AnyLAN
Based on Ethernet std.
Access: Demand Priority
Speed: 100 Mbps
Media: Twisted pair or fiber optic
Physical Topology: star
Logical Topology: bus
X3T9.5
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FDDI (Fiber Distributed Data Interface)
Developed by ANSI
Access: Token passing
Speed: 100 Mbps
Media: fiber optic
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Or Twisted pair (CDDI)
Physical Topology: star
Logical Topology: ring (dual ring)