Transcript Module 1 Internetworking Basics

Introduction to
Network
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Computer Networks
Primary purposes of network is to
increase productivity.
 The minimum requirements for setting
up a network are:
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An NIC card
 Network Media
 Connectors
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Network Interface Circuit
(NIC) Card
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IS a printed circuit board that provides
network communication capabilities to and
from a PC.
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Amplifies electronic signals
Package data for transmission
Physically connects computer to
transmission media
Each NIC card is stored with a unique
address provided by IEEE called MAC
address.
MAC is a 48 bit address, the first 24 bits is
the vendor code and the next 24 bits
represent the Serial Number.
Network Media
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IS the actual physical environment which
data travels as it moves from one computer
to another, and it connects network devices.
The most common types of network media
are:
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Coaxial Cables
Twisted Pair Cables
Fiber Optic Cables
Wireless
Coaxial Cables
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Consists of
 Single copper conductor
 Plastic insulation
 Over a wire mesh( Braided Copper Shielding)
 Another plastic insulation.
Used to connect dish antenna to a TV set.
Coaxial Cables are of two types:
 Thicknet (longest distance )
 Thinnet
Connectors used:
BNC
T
Terminators.
Twisted Pair Cables
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Used for both LANs and telephone systems.
Composed of four color-coded pairs of
copper conductors twisted around each
other.
The outer jacket provides protection and
keeps the pairs in alignment.
There are two types:
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Unshielded Twisted Pair Cable (UTP)
Shielded Twisted Pair Cable (STP)
Twisted Pair Cables
Unshielded Twisted Pair Cable (UTP)
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Used in normal office environments.
IS the most popular network media.
Connectors used is RJ 45 connectors.
Twisted Pair Cables
Unshielded Twisted Pair Cable (UTP)
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The advantage of UTP is its ability to limit
signal degradation from electromagnetic
interference (EMI) and Radio frequency
interference.
Reduces Crosstalk
There are different categories of UTP cable.
The most used is CAT5 –have the
maximum segment length 100m.(shorter
than coax)
Twisted Pair Cables
Unshielded Twisted Pair Cable (UTP)
Implementation
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Straight through Cable
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Used for
• Switch to router
• Switch to PC or server
• Hub to PC or server
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Twisted Pair Cables
Unshielded Twisted Pair Cable (UTP)
Implementation
 Crossover Cable (pins 1 and 2 on one connector connect to pins 3
and 6 on the other)
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Used for
• Switch to switch
• Switch to hub
• Hub to hub
• Router to router
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PC to PC
Twisted Pair Cables
Unshielded Twisted Pair Cable (UTP)
Implementation
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Roll-over Cable
(pins 1 on one connector connect to pins 8 on the
other)
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Used for
• Console port of a router or switch to the PC
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Twisted Pair Cables
shielded Twisted Pair Cable (STP)
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Protect against signal degradation.
Each pair of wires is wrapped in a metallic foil.
The four pairs of wires are then wrapped in an
overall metallic braid or foil.
Twisted Pair Cables
shielded Twisted Pair Cable (STP)
Reduces electrical noise within and
outside the cable.
 Used in Token Ring.
 Maximum segment length is 100m
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Fiber Optic Cables
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Capable of conducting modulated light
transmission.
Consists of two fibers encased in
separate sheaths.
A cable, consisting of a center glass core
surrounded by layers of plastic, that
transmits data using light rather than
electricity.
Connectors used are multimode.
Not effected by EMI
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There are two types of fiber-optic cables:
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Single-mode
Multimode
Fiber Optic Cables
Single-mode
Allow only one mode of light to
propagate through the fiber.
 Capable of higher bandwidth and
greater distances
 Uses Lasers as the light-generation
method and is expensive.
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Fiber Optic Cables
Multimode
Allows multiple modes of light to
propagate through the fiber.
 Often used for workgroup
applications.
 The segment length is less than the
single-mode.
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Wireless
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The device use to signal distribution called wireless
hub or access point
To receive the signal from the access point the pc
needs to install wireless (NIC)
Radio frequency (RF)
• Transmit voice, video and data
• Affected by electromagnetic interference
• Limited distance
Wireless LAN (WLAN) use radio waves, microwave
and Infrared waves.
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Network Topologies
The configurations of network components
 Widely used network topologies
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Bus
Star
Extended star
Ring
Mesh
Partial Mesh
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Bus Network Topology
Most simple network topology
 All devices connected to a common central
cable (wire or other media )
 Inexpensive
 Easily expanded
 If cable fails, the entire network will shut down
 Earlier Ethernet commonly implement a bus
topology
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Bus Network Topology (Continued)
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Star Network Topology
Star topology is centered around central
routing device called a switch or a hub by
point-to-point links.
 All network nodes connect to the hub
 Easy to install and update
 If hub fails, network fails
 Disadvantage that it require more cabling
therefore, higher cost than the bus.
 Extended star
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Ring Network Topology
Each node connected to two other nodes in a
ring
 Similar to the buss, but with the ends of the
buss connected together by unidirectional
transmission link to form a single closed loop.
 Each station on the network connects to the
network at a repeater.
 Expensive and difficult to install
 One example of a ring topology is Token Ring
networks
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Ring Network Topology
(Continued)
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Dual-Ring
Tow rings allow data to be sent in both
directions
 Creates redundancy.
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Mesh Network Topology
Every node connected to every other node
 Fast
 Reliable
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Expensive
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No hub or bus to fail
If one device goes down, it is the only node
affected
Every node must be wired to every other node
Difficult to add nodes
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If there are 32 nodes in a mesh network and
you wish to add a new node, how many new
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cables
must you add?
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Partial Mesh
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At least one derive is connected to all
other devices without being fully
meshed.
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