The document discusses computer networks and their key components. It defines a computer network as a group of computers linked together that allows them to communicate and share resources. It then describes the main types of networks as local area networks (LANs) for geographically close computers, and wide area networks (WANs) for computers farther apart connected by telephone lines or radio waves. The document proceeds to outline some common network topologies (arrangements) including star, ring, bus and tree configurations, and notes advantages and disadvantages of each.

1. Mrs.S.Chitradevi
Assistant Professor in Commerce with CA
E.M.G.Yadava Women’s College
Madurai-14

2. A C o m p u t e r N e t w o r k i s a G ro u p O f C o m p u t e r s l i n k e d t o e a c h o t h e r
t h at e n a b l e s t h e C o m p u t e r t o C o mm u n i c at e w it h a n o t h e r C o m p u t e r
a n d s h a re t h e i r R e s o u rc e s , D at a , a n d A p p l i c at i o n s .
Te l e c o m m u n i c at i o n i s t h e s e n d i n g o f i n fo r m at i o n i n a n y fo r m f ro m
o n e p l a c e t o a n o t h e r u s i n g e l e c t ro n i c o r l i g h t e m i t t i n g m e d i a .
COMPUTER NETWORKS

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Types of Networks
1) LAN –Local Area Network  The Computers are
geographically close together (that is, in the same
building).
2) WAN – Wide Area Network  The Computers are
farther apart and are connected by telephone lines
o radio waves.

4. Characteristics of Networks
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 Topology – The geometric arrangement of a
computer.
 Protocol – Defines a common set of rules and
signals that computers on the network use to
communicate.
 Architecture – Peer to peer or Client/Server.

5. LAN Network
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6. LAN Network
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 LAN is a network with small area.
 It is used in a single building or group of building.
 It can be connected another LAN using telephone lines &
radio waves.
 Most LANs connect workstations & personal computers.
 LAN comes under different types and they are
 LAN can transmit data at very fast rate but the distance is
limited.
Token-ring, Ethernet & ARC nets

7. WAN Network
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Connecting one or more LAN is called WAN

8. WAN Network
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9. WAN Network
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 A WAN is a network with large geographical area.
 Computers connected to WAN use public networks.
 They can also connected through leased lines or
satellites.
 The Largest WAN in existence is the Internet.

10. Network Topology
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Network
Topology
Star
Ring
Bus
Tree

11. Star Topology
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12. Star topology
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 It is designed with each node connected directly to
a central hub.
 The hub controls all functions of the network. It act
as a repeater for the data.
 Used to connect one or more small computers.

13. Star topology
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Easy to install and wire.
No disruptions to the network.
Easy to detect faults and tom
remove parts.
Requires more cable length.
If the hub fails, nodes attached
are disabled.
More expensive.
Advantages Disadvantages

14. Ring topology
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15. Ring topology
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 It can be as simple as a circle or point-to-point
connections of computers.
 It has no central hub, all nodes are connected in a
closed loop.
 Access and control of ring networks are maintained
by a “token-passing system.

16. Ring topology
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Growth of System has minimal
impact on performance.
All stations have equal access.
Most expensive.
Failure of one computer may
impact others.
Complex.
Advantages Disadvantages

17. Bus topology
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18. Bus topology
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 It consists of a main run of cable with a terminator
at each end.
 All nodes are connected to the linear cable.
 All communications are carried on a common cable
or bus.

19. Bus topology
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Easy to connect a computer to a
linear bus.
Requires less cable length than
others.
Entire network shuts down if there
is a break in the main cable.
Difficult to identify the problem.
Advantages Disadvantages

20. Tree topology
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21. Tree topology
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 It combines the characteristics of bus and star
topologies.
 It consist of groups of star configured workstations
connected to a linear bus.
 It allow for the expansion of an existing netwrok.

22. Tree topology
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Point-to-point wiring for individual
segments.
Supported by several hardware
and software vendors.
Overall length of each segment is
limited by the type of cabling
used.
If the backbone line breaks, entire
segment goes down.
Advantages Disadvantages

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