Wire Media: UTP

1
Wire Media UTP

• Unshielded Twisted Pair (UTP)
• Ordinary copper wire
• Twisted several times per inch to reduce
  interference
• Pair of wires needed for a complete electrical
  signal
• Unshielded nothing but plastic coating
• No protection from interference

2
Wire Media UTP

• Unshielded Twisted Pair (UTP)
• Business telephone wiring traditionally comes in
  4-pair UTP wire bundles
• Used in LAN wiring to use existing building
  wiring technology

3
Wire Propagation RJ-45

• RJ-45 connector terminates a UTP bundle
• Slightly wider than RJ-11 residential connector
• Width needed for 8 wires

4
Wire Media UTP to the Desktop

• UTP
• Dominant for line from desktop to first hub or
  switch
• Inexpensive to buy and install
• Rugged can take punishment of office work
• Easily 100 Mbps, 1 Gbps with careful insulation

UTP
First Hub or Switch
5
Wire Media Optical Fiber

• Optical Fiber
• Glass core, surrounding glass cladding
• Light source turned on/off for 1/0
• Total internal reflection at boundary
• Almost no attenuation

Cladding
Core
Light Source
Reflection
6
Wire Media Optical Fiber

• Limited by Distortion
• Light entering at different angles travels
  different distances (different number of
  reflections)
• Called different modes
• Light from successive bits becomes mixed over
  long distances

Light Source
7
Wire Media Optical Fiber

• Multimode Fiber
• Wide core makes easy to splice (50 or 62 microns)
• Many angles for rays (modes)
• Short propagation distance (usually 200 m to 500
  m)

Mod B
Light Source
8
Wire Media Optical Fiber

• Single Mode Fiber
• Narrow core difficult to splice (5 or 8 microns)
• Only one angle for rays (one mode), so (almost)
  no distortion
• Longer propagation distance (usually up to 2 km
  for LAN fiber, longer for long-distance fiber)
• Narrow core makes fiber fragile and difficult to
  splice

9
Wire Media Optical Fiber

• Optical Fiber
• High speeds over long distances
• 200 m to 2 km
• Costs more than UTP, but worth it on long runs
• Good for all links between hubs and switches
  within and between buildings in a site network

Optical Fiber
10
Wire Media UTP and Optical Fiber

• The emerging pattern UTP from first hub or
  switch to desk, Fiber everywhere else on site

11
Wire Media Coax

• Coaxial Cable
• Used in cable TV, VCRs
• Central wire, external concentric cylinder
• Outer conductor wrapped in PVC

Inner Wire
Outer Conductor Wrapped in PVC
Screw-On Connector
12
Wire Media Coaxial Cable

• Coaxial Cable
• Installed widely today in old 10 Mbps Ethernet
  LANs
• Not being used in new installations
• Optical fiber more cost-effective for long links
• UTP more cost-effective for desktop links