Chapter 2 Topologies
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Transcript of Chapter 2 Topologies
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Chapter 2 1
Topologies
Chapter 2
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Chapter 2 2
Chapter Objectives
Explain the different topologies
Explain the structure of various topologies Compare different topologies
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Chapter 2 3
Recall
LAN types are Ethernet, Token Ring, Token bus and
Fiber Distributed Data Interface (FDDI).
OSI layers are Physical, Data Link, Network,
Transport, Session, Presentation and Applicationlayer
The factors of network selection criteria are
Performance, Reliability and Security
Standards organization is unit which develops,maintains, improves, amends and revises standards
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Chapter 2 4
Introducing Topologies
Topology refers to physical or logical arrangement of
network
Physical topologies are
Single Node Bus
Star
Ring
Mesh Tree
Hybrid
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Chapter 2 5
Single Node Topology - I
Single device, at times device called dumb terminal
is connected to the server
Devices operates on files from server and returns
them back after completing task
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Chapter 2 6
Single Node Topology - II
Advantages:
Easy to install,configure and manage
Least expensive
Single cable is required
Disadvantages:
Network consists ofsingle device
Dumb terminal isdependent on server
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Chapter 2 7
Bus topology - I
All devices are connected to a common cable calledtrunk
Maximum segment length of cable is 200 m
Maximum of 30 devices per segment
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Chapter 2 8
Bus topology - II
Server is at one end and devices are at different
positions
50 ohm terminator is used
Devices are not responsible for data transmission Number of collisions are more
Daisy chain method can be used to add more
devices
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Chapter 2 9
Bus topology - III
Advantages:
Installation of devicesis easy
Requires less cablecompared to startopology
Less expensive andworks better for smallernetworks
Disadvantages:
If backbone breaks,entire network gets
down
Difficult to isolateproblems
Limited number ofdevices
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Chapter 2 10
Star Topology - I
Each device is connected to a central device calledhub through cable
Data passes through hub before reachingdestination
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Chapter 2 11
Star Topology - II
Advantages:
Easy to install,configure, manage and
expand
Centralizedmanagement
Addition or removal ofdevice does not affectthe whole network
Disadvantages:
Requires more cable
Failure of hub affectsentire network
More Expensive
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Chapter 2 12
Case Study 1
Hyderabad branch of the MoneyMaker bank has builtan insurance department in such a way that eachdevice is connected to one another. This department
consists of seven agents. It is required that agentsshould handle only their specific clients since theinformation is confidential. But in the existing topologythe data is not secured. So, Smith, the networkadministrator, wants to switch over to other topology.
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Chapter 2 13
Problem
Design a new type of network for this department.
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Chapter 2 14
Suggested Solution
The current topology implemented by the bank is
mesh in which information is shared between differentdevices. To obtain security of data star network seems
to be the best choice. It also provides ease of
troubleshooting, centralized management and ease of
reconfiguration.
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Chapter 2 15
Ring Topology - I
Devices are connected
in a closed loop
All devices have equal
access to media Device waits for its turn
to transmit
Most common type is
Token Ring
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Chapter 2 16
Ring Topology - II
Advantages:
Data travels at greater
speed
No collisions
Handles large volumeof traffic
Disadvantages:
More cabling is
required compared tobus
One faulty deviceaffects the entire
network
Addition of devicesaffect network
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Chapter 2 17
Dual Ring Topology
Consists of two
independent primary
and secondary rings
Secondary ring is
redundant, used only
when primary stops
functioning
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Chapter 2 18
Mesh Topology - I
Used in WANs to
interconnect LANs
Every device is
connected to everyother device
Use routers to
determine the best path
of communication
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Chapter 2 19
Mesh Topology - II
Types
Full mesh Partial mesh
Full mesh topology All devices are connected to
each other
Partial mesh topology - Some devices are
connected to only those with whom they exchange
most of the data
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Chapter 2 20
Mesh Topology - III
Advantages:
Improves fault
tolerance
Failure of one linkdoes not affect entirenetwork
Centralizedmanagement is notrequired
Disadvantages:
Difficult to install and
manage
Each link from one
device to other
requires individual NIC
Very much expensive
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Chapter 2 21
Tree Topology - I
Connects groups of star
networks
Devices are wired to
root hub Root hub is connected
to second level devices
Lowest level devices
are smaller computers
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Chapter 2 22
Tree Topology - II
Advantages:
Easy to add new
devices
Point-to-point wiring foreach device
Fault detection is easy
Disadvantages:
Difficult to configure
If backbone breaks,
entire network goesdown
More expensive
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Chapter 2 23
Hybrid Topology - I
Combines two or more different physical topologies
Commonly Star-Bus or Star-Ring
Star-Ring uses Multistation Access Unit (MAU)
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Chapter 2 24
Hybrid Topology - II
Advantages:
Used for creating
larger networks
Handles large volumeof traffic
Fault detection is easy
Disadvantages:
Installation andconfiguration is difficult
More expensive thanother topologies
More cabling isrequired
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Chapter 2 25
Case Study 2
MoneyMaker Bank at Mumbai has implemented a
star topology in their IT department.All computers
are connected to the central switch. In the Loandepartment, all computers are connected in closed
loop format. Network administrator, John wants to
connect these two networks so that data can be
shared among different departments.
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Chapter 2 26
Problem
Connect two different departments
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Chapter 2 27
Suggested Solution
The administrator can join these two star and ring
networks to form a hybrid network with the help of
MultistationAccess Unit (MAU). It is a centralizedhub. Ensure that there is no break in the link
between two computers in a ring network and switch
in star network is working properly.
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Chapter 2 28
Summary - I
Network is an interconnection of many
communicating entities that are connected for the
purpose of data communication
Topology describes the way in which networkingdevices are connected to each other
Physical topologies are how the wires are
interconnected, while logical topology is how the
network behaves and interoperates Different types of topologies are Single Node, Star,
Bus, Ring, Mesh, Tree and Hybrid
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Chapter 2 29
Summary - II
In a single node topology, just a single device calleddumb terminal is connected to the server
Bus topology connects each device to a single cable
and at either end of the cable terminator is used toremove unsent data from the cable
In star topology, multiple devices are connected to acentral connection point known as hub or switch
In a ring topology, data travels around the loop inone direction and passes through each device
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