Module 7 Chapter 6 Ethernet Technologies

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Module 7Chapter 6 Ethernet Technologies
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10-Mbps Ethernet

• Legacy Ethernet
• 10BASE5, 10BASE2, and 10BASE-T
• Four common features of Legacy Ethernet
• Timing parameters
• Frame format
• Transmission process
• Basic design rule

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10-Mbps Ethernet

• 10BASE5

Single thick coaxial cable bus Cable is large and heavy
Primary benefit was length (500m) Only in half-duplex
Inexpensive Sensitive to signal reflection
No configuration Not for new installations
Components are difficult to find Difficult to install
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10-Mbps Ethernet

• 10BASE2

Uses half-duplex Compared to 10Base5
Components are difficult to find Low cost
No need for hubs Smaller size, lighter weight
Not for new installations Greater flexibility
Thin net Installation easier
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10-Mbps Ethernet

• 10BASE-T

Cheaper and easier to install Extended Star
Category 3 Originally half-duplex protocol
Category 5 Full-duplex features added later
Category 5e New installations Cat5e or better
Uses a hub 10 Mbps in half-duplex mode
Star topology 20 Mbps in full-duplex mode   
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Wiring and Architecture

• 5-4-3 rule
• No more than five segments
• Separated by no more than four repeaters.
• No more than three populated segments between any
  two distant stations
• Hubs or repeaters merely extend the length of a
  network segment within a single collision domain
• Bridges and switches divide a segment into
  separate collision domains

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Manchester Encoding

• Manchester encoding is used in 10 Mbps systems
• The direction of the edge transition in the
  middle of the timing window determines the binary
  value

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100-Mbps Ethernet

• 100-Mbps Ethernet is also known as Fast Ethernet
• 100BASE-TX is copper UTP
• 100BASE-FX is multimode optical fiber
• Three common characteristics
• Timing parameters
• Frame format
• Parts of the transmission process

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100-Mbps Ethernet

• Timing parameters
• One bit time in 100-Mbps Ethernet is 10nsec
• Frame format
• 100-Mbps frame format is the same as the 10-Mbps
  frame
• Parts of the transmission process
• Two separate encoding steps are used
• The first part of the encoding uses a technique
  called 4B/5B
• The second part of the encoding is the actual
  line encoding specific to copper or fiber

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100-Mbps Ethernet

• 100BASE-TX uses 4B/5B encoding which is then
  scrambled
• Converted to multi-level transmit-3 levels or
  MLT-3.
• Half-duplex 100 Mbps
• Full-duplex 200 Mbps

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Fast Ethernet Architecture

• Fast Ethernet links consist of a connection
  between a station and a hub or switch
• Hubs are considered multi-port repeaters
• Switches are considered multi-port bridges
• These are subject to the 100 m UTP distance
  limitation

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Fast Ethernet Architecture

• Class I repeater
• Any repeater that changes between one Ethernet
  implementation and another
• 140 bit-times of latency
• Class II repeater
• 92 bit-times latency
• Cable between Class II repeaters may not exceed 5
  meters

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Fast Ethernet Architecture

• Signaling scheme is inherently full duplex
• Half duplex are not uncommon
• Half duplex is undesirable
• Switches have made the 100m limitation less
  important
• Workstations are located within 100m of the
  switch
• 100 m distance starts over at the switch

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1000-Mbps Ethernet

• 1000-Mbps Ethernet or Gigabit Ethernet
  Transmission
• Fiber and copper media  
• The 1000BASE-X IEEE 802.3z
• Specifies 1 Gbps full duplex over optical fiber
• 1000BASE-TX, 1000BASE-SX, and 1000BASE-LX
• Timing parameters
• 1 nanosecond or 1 billionth of a second bit time.
• Frame Format
• Same format used for 10 and 100-Mbps Ethernet
• Transmission
• Depending on the implementation

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1000-Mbps Ethernet

• 1000BASE-T (IEEE 802.3ab) was developed to
  provide additional bandwidth for
• Intra-building backbones
• Inter-switch links
• Server farms
• Connections for high-end workstations
• Supports both half-duplex and full-duplex
• Fiber-based Gigabit Ethernet (1000BASE-X)
• Uses 8B/10B encoding (similar to 4B/5B)
• This is followed by Non-Return to Zero (NRZ) line
  encoding

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1000Base-LX/SX

• Common to all versions of 1000 Mbps
• Timing
• Frame format
• Transmission
• NRZ signals are pulsed into the fiber
• Short-wavelength (1000BASE-SX )
• Long-wavelength (1000BASE-LX)
• Media Access Control
• Link as point-to-point
• Separate fibers
• Transmitting (Tx)
• Receiving (Rx)
• Inherently full duplex

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Gigabit Ethernet

• Gigabit Ethernet is the dominant technology for
• Backbone installations,
• High-speed cross-connects
• General infrastructure

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10 Gigabit Ethernet

• IEEE 802.3ae, governs the 10GbE family
• Provide increased bandwidth
• Interoperable with existing infrastructure
• Implementations being considered
• 10GBASE-SR
• 10GBASE-LX4
• 10GBASE-LR and 10GBASE-ER
• 10GBASE-SW, 10GBASE-LW, and 10GBASE-EW

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10 Gigabit Ethernet

• 10GBASE-SR
• short distances, supports a range between 26 m to
  82 m
• 10GBASE-LX4
• Uses wide wavelength division multiplexing (WWDM)
• 240 m to 300 m over multimode fiber
• 10 km over single-mode fiber
• 10GBASE-LR and 10GBASE-ER
• Support 10 km and 40 km over single-mode fiber
• 10GBASE-SW, 10GBASE-LW, and 10GBASE-EW
• Known collectively as 10GBASE-W
• Works with OC-192 synchronous transport module

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Future of Ethernet

• The future of networking media is three-fold
• Copper (up to 1000 Mbps, perhaps more)
• Wireless (approaching 100 Mbps, perhaps more)
• Optical fiber (currently at 10,000 Mbps and soon
  to be more)
• Copper and wireless media have certain physical
  and practical limitations
• Limitations on optical fiber are
• Electronics technology
• emitters and detectors
• Fiber manufacturing processes
• Developments in Ethernet
• Heavily weighted towards Laser light sources
• Single-mode optical fiber

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The End Break Time