Thinnet (10Base2)

1
Thinnet (10Base2)

• Characteristics (cont.)
• Size and scalability
• Allows a maximum of 185 m per network segment
  (see Figure 4-20)
• Noise immunity
• More resistant than twisted-pair wiring
• Less resistant Thicknet

Figure 4-19 Thinnet BNC connectors
2
Thinnet (10Base2)

• Signal bounce
• Caused by improper termination on a bus network
• Travels endlessly between two ends of network
• Prevents new signals from getting through

Figure 4-20 A 10Base2 Ethernet network
3
Twisted-Pair (TP) Cable

• Color-coded pairs of insulated copper wires
  twisted around each other and encased in plastic
  coating
• Twists in wire help reduce effects of crosstalk
• Number of twists per meter or foot known as twist
  ratio
• Alien Crosstalk
• When signals from adjacent cables interfere with
  another cables transmission

Figure 21 Twisted-pair cable
4
Shielded Twisted-Pair (STP)

• STP cable consists of twisted wire pairs that are
  individually insulated and surrounded by
  shielding made of metallic substance

Figure 4-22 STP cable
5
Unshielded Twisted-Pair

• Consists of one or more insulated wire pairs
  encased in a plastic sheath
• Does not contain additional shielding

Figure 4-23 UTP cable
6
Unshielded Twisted-Pair

• To manage network cabling, it is necessary to be
  familiar with standards used on modern networks,
  particularly Category 3 (CAT3) and Category 5
  (CAT5)

Figure 4-24 A CAT5 UTP cable
7
Unshielded Twisted-Pair

• CAT1 2 wire pairs suitable for voice only
• CAT2 4 wire pairs up to 4 Mbps throughput
• CAT3 4 wire pairs up to 10 Mbps and 16 Mhz
  signal
• CAT4 4 wire pairs up to 10 Mbps
• CAT5 4 wire pairs up to 100 Mbps and 100 Mhz
  signal
• CAT5e up to 200 Mhz signal
• CAT6 additional foil insulation 6x throughput
  than CAT5
• CAT7 unfinished standard up to 1Ghz

8
10BaseT

• Popular Ethernet networking standard that
  replaced 10Base2 and 10Base5 technologies
• T for twisted pair

Figure 4-25 A 10BaseT Ethernet network
9
10BaseT

• Enterprise-wide network
• Spans entire organization
• Often services needs of many diverse users

Figure 4-26 Interconnected 10BaseT segments
10
100BaseT

• Enables LANs to run at 100-Mbps data transfer
  rate
• Also known as Fast Ethernet
• Two 100BaseT specifications have competed for
  popularity as organizations move to 100-Mbps
  technology
• 100BaseTX
• 100BaseT4 (can use CAT3 cabling)

11
100BaseVG

• Cousin of Ethernet 100 Mbps technologies
• VG stands for voice grade
• Also called 100VG-AnyLAN
• Originally developed by Hewlett-Packard and ATT
• Now governed by IEEE standard 802.12
• Requires more sophisticated NICs and can reduce
  network performance

12
Comparing STP and UTP

• Throughput
• Both can transmit up to 100 Mbps
• Cost
• Typically, STP is more expensive
• Connector
• Both use RJ-45 connectors and data jacks
• Noise immunity
• STP is more noise-resistant
• Size and scalability
• Maximum segment length for both is 100 meters

13
Fiber-Optic Cable

• Contains one or several glass fibers at its core
• Surrounding the fibers is a layer of glass called
  cladding

Figure 4-28 A fiber-optic cable
14
Fiber-Optic Cable

• Single-mode fiber
• Carries light pulses along single path
• Multimode fiber
• Many pulses of light generated by LED travel at
  different angles

Figure 4-29 Single-mode and multimode
fiber-optic cables
15
Fiber-Optic Cable

• Throughput
• Reliable in transmitting up to 1 gigabit per
  second
• Cost
• Most expensive type of cable
• Connector
• You can use any of 10 different types of
  connectors

16
Fiber-Optic Cable

• Two popular connectors used with fiber-optic
  cable
• ST connectors
• SC connectors

Figure 4-30 ST and SC fiber connectors
17
Fiber-Optic Cable

• Noise immunity
• Unaffected by either EMI or RFI
• Size and scalability
• Network segments made from fiber can span 100
  meters
• Signals transmitted over fiber can experience
  optical loss

18
10BaseF and 100BaseFX

• 10BaseF
• Physical layer standard for networks specifying
  baseband transmission, multimode fiber cabling,
  and 10-Mbps throughput
• 100BaseFX
• Physical layer standard for networks specifying
  baseband transmission, multimode fiber cabling,
  and 100-Mbps throughput

19
Physical Layer Networking Standards
Table 4-3 Physical layer networking standards
20
Cable Design and Management

• 1991 TIA/EIA released its joint 568 Commercial
  Building Wiring Standard
• TIA Telecommunication Industry Assoc.
• www.tiaonline.org
• EIA Electronic Industries Assoc.
• www.eia.org
• T568A
• T568B

21
Cable Design and Management

• Cable plant
• Hardware comprising enterprise-wide cabling
  system
• Structured cabling
• Method for uniform, enterprise-wide, multivendor
  cabling systems

Figure 4-31 TIA/EIA structured cabling subsystems
22
Cable Design and Management

• Entrance facilities
• Backbone wiring
• Backbone cabling that provides vertical
  connections between floors of a building are
  called risers

Table 4-4 TIA/EIA specifications for backbone
cabling
23
Cable Design and Management

• Equipment room
• Telecommunication closet
• Punch-down block is a panel of data receptors
• Patch panel is a wall-mounted panel of data
  receptors

Figure 4-32 Patch panel (left) and punch-down
block (right)
24
Cable Design and Management

• Horizontal wiring
• Max distance is 100m

Figure 4-33 Horizontal wiring
25
Cable Design and Management

• Work area
• Patch cable is a relatively short section of
  twisted-pair cabling with connectors on both ends
  that connect network devices to data outlets

Figure 4-34 Standard TIA/EIA wall jack
26
Cable Design and Management
Figure 4-35 A structured cabling hierarchy
27
Installing Cable
Figure 4-36 A typical UTP cabling installation
28
Installing Cable
T568A Standard
Table 4-5 Pin numbers and color codes for an
RJ-45 connector
29
Installing Cable

• Straight-through cable
• Terminations at both ends are identical
• Crossover cable
• Terminations locations of transmit and receiver
  wires on one end of cable are reversed

Figure 4-37 RJ-45 terminations on a crossover
30
Installing Cable

• Do not untwist twisted-pair cables more than
  one-half inch before inserting them
• Do not strip off more than one inch of insulation
  from copper wire in twisted-pair cables
• Watch bend radius limitations for cable being
  installed
• Test each segment of cabling with cable tester
• Use only cable ties to cinch groups of cable
  together

31
Installing Cable

• Avoid laying cable across floor where it may
  sustain damage
• Install cable at least three feet away from
  fluorescent lights or other sources of EMI
• Always leave slack in cable runs
• If running cable in plenum, area above ceiling
  tile or below subflooring, make sure cable sheath
  is plenum-rated
• Pay attention to grounding requirements

32
Atmospheric Transmission Media

• Infrared transmission
• Infrared networks use infrared light signals to
  transmit data through space
• Direct infrared transmission depends on
  transmitter and receiver remaining within line of
  sight
• In indirect infrared transmission, signals can
  bounce off of walls, ceilings, and any other
  objects in their path

33
Atmospheric Transmission Media

• RF transmission
• Radio frequency (RF) transmission relies on
  signals broadcast over specific frequencies
• Very susceptible to interference
• Two most common RF technologies
• Narrowband
• Concentrates RF energy at a single frequency
• Spread spectrum
• Distributed over several frequencies
  simultaneously

34
Choosing the Right Transmission Media

• Areas of high EMI or RFI
• Corners and small spaces
• Distance
• Security
• Existing infrastructure
• Growth