Topology and Cabling

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Chapter 3

• Topology and Cabling

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Building a Network

• Step 1. Connecting all computers physically by
  using various networking hardware
• Step 2. Installing networking software in each
  computer

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Network Topology

• What is Network Topology?
• Physical topology
• Logical topology

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Physical Topology versus Logical Topology

• Physical topology
• The way that the computers are physically
  connected to one another
• Logical topology
• The way that the signals travel over the network
  from one computer to the next without regard to
  the physical interconnection of the computers

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Network Topology

• What are the four basic Network Topologies?
• Bus topology (physical and logical topology)
• Ring topology (physical and logical topology)
• Star topology (physical topology)
• Mesh topology (physical topology)

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Bus Topology

• What is the Bus Topology?
• All computers are connected to a main line (BUS
  CABLE (BUS) (physical bus topology)

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Bus Topology

• What are the characteristics of the Bus Topology?
• When a computer transmits data, the signal
  travels down the BUS in both directions and
  reaches all of the other computers (logical bus
  topology)
• At the two open ends of a bus, there are
  terminators to kill/destroy/absorb the signal.
• The main disadvantage of the Bus Topology
• A single faulty terminator or a break in the BUS
  causes the signal to bounce back into the
  network, and therefore, creates a continuously
  busy network

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Bus Topology
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Ring Topology

• What is Ring Topology?
• All computers are attached to one another to form
  a closed loop (a ring) (physical ring topology)
• Information is passed from one computer to
  another in either clock-wise direction or counter
  clock-wise direction (logical ring topology) and
  after receiving the information, the receiver
  must send the acknowledgement message (ACK
  message) back to the sender to complete the
  transmission. As a result, when one computer or
  ring cable fails, the whole network fails.
• ACTIVE TOPOLOGY
• EACH computer actively participates in
  information delivery (actively passing
  information to another computer)
• Every computer in a ring network is a repeater to
  regenerate the signal that has been
  attenuated/weakened

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Ring Topology
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Ring Topology

• What are the characteristics of the Ring
  Topology?
• The main disadvantage
• Break in one of the computers or the RING CABLE
  fails the entire network

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Star Topology

• What is Star Topology?
• All computers are connected to a central wiring
  point/device (i.e., hub)
• Only physical topology (NO logical star topology)
• The signal in a star topology will travel based
  on BUS or RING logical topology

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Star Topology

• What are the characteristics of the Star
  Topology?
• Every computer has its own dedicated connection
  to the hub.
• Hence, if a single cable fails, only the
  computer connected to the hub by that cable is
  affected
• better fault tolerance than bus and ring
• The main disadvantage
• A faulty hub fails the entire network

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Star Topology
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Mesh Topology

• What is Mesh Topology?
• Pure mesh topology
• Each computer has a direct, dedicated line to
  every other computer in the network

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Mesh Topology
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Mesh Topology (Fully Connected Topology)

• What are the characteristics of the Mesh
  Topology?
• Advantage
• Resilience
• Disadvantage
• Difficult and expensive to build in WIRE/CABLE
  network. More common in WIRELESS network

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Network Technology

• What is Network Technology (Standard)?
• The actual PHYSICAL and DATA LINK layer
  technology standard that provides a method for a
  computer to share resource(s) with other
  computer(s)

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Examples of Network Technology

• Ethernet
• A family of network technologies to build LAN
• 10 Base 5 (Thicknet)
• 10 Base 2 (Thinnet)
• 10 Base T
• 100 Base T
• 100 Base F
• 1000 Base T
• 1000 Base F
• Token Ring (out of date)
• A family of network technologies to build LAN

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Network Technology networking hardware

• Network technology defines all of the networking
  hardware that must be used
• If using 10 Base 5 Ethernet, then you will have
  to use 10 Base 5 NIC, thicknet coaxial cable, ...
• If using 100 Base T, then you will have to use
  100 Base T NIC, UTP cable, ...
• If using 100 Base F, then you will have to use
  100 Base F NIC, fiber optic cable, ...

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Communication Media Wire/Cable Media

• Coaxial Cable
• RG-8
• RG-58
• Twisted Pair Cable
• STP
• UTP
• Fiber Optic Cable

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Coaxial Cable

• Designed to protect data transmission from
  electromagnetic interference (EMI)
• The signal travels in the center wire
• Two examples of coaxial cable
• RG-8, RG-58
• Use in the Old Ethernet technology (10Base5,
  10Base2)

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RG-8

• Thick Ethernet (Thicknet, 10Base5) cable
• Transmission Rate - 10 Mbps
• Maximum Length (without Repeaters) - 500
  meters/segment
• Uses transceivers and AUI (Attachment Unit
  Interface) cable
• 2.5 meter between two consecutive connections
• Up to 100 nodes per segment/segment

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RG-8
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Transceiver
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RG-58

• Thin Ethernet (Thinnet, 10Base2) cable
• Transmission Rate - 10 Mbps
• Maximum Length (without Repeaters) - 185 meters
• BNC (Bayonet-Neill-Concelman) connections
• Minimum 0.5 meter between two consecutive
  connections
• Maximum 30 nodes per segment

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RG-58
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Twisted Pair

• STP
• The shielding protects data transmission from
  electromagnetic interference (EMI)
• It is used in the Token Ring technology
• UTP
• No shielding
• Most popular cable (because it is the cheapest
  and good enough for most environments)
• CAT rating (CAT1, CAT2, CAT3, CAT4, CAT5, CAT5e,
  CAT6)
• Rated in MHz
• Indicating the highest frequency (data
  transmission rate/speed) the cable can handle
• It comes in different numbers of pair (e.g., 2
  pairs, 4 pairs)

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Fiber Optic Cable

• It transmits light
• The three basic parts
• Fiber where the light travels
• Cladding that makes the light reflects down the
  fiber
• Insulating jacket
• Two types of lights
• Light generated by LED
• Laser light
• High bandwidth (high data transmission rate/speed)

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Fiber Optic Cable

• Multimode Fiber Optic Cable
• LED light
• Slower
• Shorter distance data transmission
• Larger diameter
• Singlemode Fiber Optic Cable
• Laser light
• Faster
• Longer distance data transmission
• Smaller diameter

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Fiber Optic Cable

• Advantages
• No EMI
• Faster
• Longer distance data transmission (5000 meters
  versus 100 meters for UTP)
• Smaller size (smaller diameter)
• More secure (difficult to tap)
• Disadvantages
• Expensive
• Difficult to install
• Fragile
• Fiber Optic cable animation
• http//www.datacottage.com/nch/fibre.htm

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Fiber Optic Cable

• Fiber optic in YouTube
• http//www.youtube.com/watch?vv1JEuzBkOD8feature
  related
• http//www.youtube.com/watch?vsOif2kjyiCEfeature
  related
• Why fiber optic? Why not satellite? (Reliability,
  capacity, speed, cost)
• http//www.betelco.com/bd/bdstel/icee.pdf

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Thicknet, Thinnet, UTP, STP, Fiber Optic
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Fire Ratings

• To reduce the risk of network cables burning and
  creating toxic fumes and smokes
• PVC
• Riser
• Plenum

• Less smoke
• Less toxic fume

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Networking Industry Standards

• What is IEEE?
• Non-profit organization
• Electrical, computer engineers
• To develop and promote the use of electronic and
  computer technology standards
• In the context of IEEE, what is 802?
• An IEEE committee whose major responsibility is
  to develop and promote the use of network
  technology standards
• What are IEEE 802.3, 802.11?
• 802.3 a sub-committee of IEEE 802 whose major
  responsibility is to develop and promote the use
  of the Ethernet network technology standards
• 802.11 a sub-committee of IEEE 802 whose major
  responsibility is to develop and promote the use
  of the wireless network technology standards