Transcript Other Ethernet Physical Layer Standards

Other Ethernet technologies
Light
Source
Other Ethernet Physical Layer
Standards
 100Base-X
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100 Mbps
100Base-TX uses Cat 5 UTP to desktop
 1000Base-X
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Gigabit Ethernet
 Traditional Ethernet (before 10Base-T)
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10Base5
10Base2
10Base5
Drop Cable
Trunk
Cable Segment
 Original Ethernet with slight changes
 Thick coaxial cables
 No hubs
 Drop cables from stations to trunk cable
 500 Meters maximum per segment
 Maximum 5 segments between farthest
stations
10Base5
15-pin DIX
Connector
AUI Drop Cable
(Attachment Unit Interface)
50 meters maximum distance
10Base5 Trunk Cable
500 meters maximum
distance
Transceiver
(Medium Attachment Unit or MAU)
10Base5 Segments
 Runs of trunk cable
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500 meters per segment (the 5 in
10Base5)
 Repeaters
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Connect trunk cable segments
Up to 5 segments between farthest two
stations
2500 meters maximum distance
Coax (Coaxial Cable)
 Signal is trapped between the two
conductors
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Signals travel far
Interference from outside signals is low
 Problem: Being squeezed out of the
market
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Cheaper UTP can now go almost as fast
Optical fiber is faster, only slightly more
expensive
Coax (Coaxial Cable)
 Widely used in
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Cable television service
To connect VCRs to televisions
 Two conductors
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Inner wire
Outer cylinder
Inner
Wire
Outer
Cylinder
Co-Axial Cable
Outer
Conductor
(cylinder)
Inner
Conductor
(wire)
Insulation
Insulation
Linking 10Base-T Hubs with 10Base5
Hub
10Base5
AUI
Connector
10Base5 Segment
500 meters maximum
Hub
Ethernet Hub with 10Base-T
and 10Base5 Ports
10Base5
DIX Connector
for AUI
To Transceiver (MAU)
on 10Base5 Trunk Cable
10Base-T
Multiple RJ-45 Jacks
for UTP Wires
To Stations and Other Hubs
10Base2
 Uses less expensive thin coaxial cable
(Cheapernet or Thinnet)
 Segment can connect up to 30 stations
 185 Meters/segment (the 2 in 10Base2)
 With repeaters, 5 segments maximum
between distant stations
Daisy Chain Layout
Segment with
3 PCs
10Base2
 NIC has BNC Connector
 T-Connector attaches to NIC BNC
connector
 Cable segments attach to tops of T
T-Connector
 Don’t
forget
terminator
Segment to Next PC
Segment to Next PC
BNC Connector
NIC
10Base2
Connection
BNC
T-Connector
NIC
Thin Ethernet (10Base2) Coaxial Cable
185m Maximum Per Segment
30 Stations Per Segment Maximum
NIC
BNC
T-Connector
NIC
Linking Hubs with 10Base2
Hub
10Base2
BNC
Connector
Hub
10Base2
Segment
185 meters maximum
Optical Fiber
 Very thin glass
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Core is where signal travels
Cladding is ring of glass around core
Core and cladding have different indices of
refraction
Cladding
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Source
Core
Single Mode Optical Fiber
 Core and cladding are very thin
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All parts of a bit’s wavefront travel the same
distance
Arrive with little distortion
Can propagate long distances
Used in telephone company long-distance links
Too expensive, difficult to install for LAN use
Cladding
Light
Source
Core
Wavefront
Multimode Optical Fiber
 Thick (usually around 62.5 micron core): easy to join
 Different parts of wavefront travel different paths:
limits distance before successive wavefronts overlap
 Multimode is most common type in LANs
 Step Index: core index of refraction is constant
across core
Cladding
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Core
Multimode Optical Fiber
 Graded Index
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Index of refraction varies along core
Rays at different angles travel similar distances
Signals travel longer distances before distortion is
bad
Multimode graded index fiber is dominant today
Cladding
Light Source
Core
10Base-F
 Standard for connecting hubs
 Can carry signals for 2,000 meters
(2Km =~ 1.2 miles)
 much farther and faster than 10Base5
Stackable Hubs
 Physically Stacked
 Can mix hubs of various types
 Easy to add capacity
 High-speed backplane or 10Base2
connectors link the stacked hubs
(switch next class meeting)
Visit 3Com for a view of actual products.
Chassis Hubs
 Chassis provides slots for expansion
boards
 Expansion boards are hubs of different
types
 Very high-speed backplane bus to link
hubs