This document discusses different types of computer networks. It describes four common network structures (topologies): star, bus, ring, and mesh. It also discusses different network types based on area covered (LAN, MAN, WAN), connection model (client-server, peer-to-peer), and purpose (storage area network, wireless network). For each topology, the key characteristics and advantages/disadvantages are provided. Different network devices like hubs, bridges, routers and switches are also explained along with their functions.

1. Computer NetworksStructure and Types
Connecting Devices
BY
Dr. SAJEEVE V.P.
2/2/2014
Dr.SAJEEVE VP
1

2. Network- meaning
Linking of two or more computers
with or without wires
so as to provide access- mutual or one way
2/2/2014
Dr.SAJEEVE VP
2

3. Network – types-
1.
2.
3.
4.
Based on structure-Star, Bus, Ring, Mesh
Based on Area- WAN, LAN, MAN
Based on status- Client-Server, Peer-Peer
Based on Purpose- Storage Area Network,
others
2/2/2014
Dr.SAJEEVE VP
3

4. 1. Network – types- Based on Structures or Topology
geometrical arrangement of devices, nodes and links,
Nodes –end point-ws, terminal, equipment, etc
Link-the comn.path- circuit, channel
1. Star Network
2. Bus Network
3. Ring Network
4. Mesh Network
2/2/2014
Dr.SAJEEVE VP
4

5. 1. STAR NETWORK
One computer at the centre
Others around it.
+
Saves cable
Fault in one node
-other nodes unaffected
No connection between nodes
Node needs to connect through cental
2/2/2014
Dr.SAJEEVE VP
5

6. STAR NETWORK- evaluation
Merits
Nodes easily added / removed
Fault in one node, other nodes unaffected
Easier to diagnose node failures.
Demerits:
If central hub fails, entire system collapses
No connection between nodes
Node needs to connect through cental
2/2/2014
Dr.SAJEEVE VP
6

7. 2. Bus network
Nodes connected in a serial
To a single main (backbone) cable
2/2/2014
Dr.SAJEEVE VP
7

8. Bus network- evaluation
Merits
Saves cable, less costly
To a single main (backbone) cable
Easy extension
Demerits:
Heavy traffic jam the network
Every adnl. connection weakens the system
Difficult to diagnose node failures
2/2/2014
Dr.SAJEEVE VP
8

9. 3.Ring network
Nodes connected in a circular cable
2/2/2014
Dr.SAJEEVE VP
9

10. 3.Ring network- evaluation
Merits
Good for small net works
Span longer distance
Demrits
Expensive
Difficult to diagnse failure
Revision interupts network.
Expansion difficult
2/2/2014
Dr.SAJEEVE VP
10

11. 4.Mesh network
Main ring line connectes every node
Besides nodes are connected mutually
2/2/2014
Dr.SAJEEVE VP
11

12. 4.Mesh network
Merits
Good large organisations
If main line fails, nodes continue to work
Less traffic jam
Demrits
Most expensive
Difficult to diagnse failure
Revision interupts network
2/2/2014
Dr.SAJEEVE VP
12

13. Network – what for? -USES
1.Sharing of resources
 Processor speed
 Storage
 Hardwares
-Peripherals connected-printer, scanner,
camera, microphone, speakers, projector
-Softare
-Internet services
2. Savings in cost / resources/ installation
2/2/2014
Dr.SAJEEVE VP
13

14. Network – what for
3. Quick, real-time two-way communication
Information / data transfer
Banking, fund transfer, email.
4. Easy and quick access to files
5. Personal touchvideo call and conference
6. Leads to efficiency-prompt employees to
report to, work in time.
7. Distributed processing
8. Less supervision-system auto-checks
2/2/2014
Dr.SAJEEVE VP
14

15. Network – risks
1. Failure of one unit in the network collapses
the entire system
2. Too much sophistication makes difficult to
manage and operate without experts
3. Data loss affects the entire system,
especially if no proper backup.
4. Cost
5. Nodes not independent- permission
2/2/2014
Dr.SAJEEVE VP
15

16. 2. Network – Types Based on area



LAN- Local Area Network
MAN- Metropolitan (medium) Area Net Work
WAN – Wide Area Network
2/2/2014
Dr.SAJEEVE VP
16

17. LANLocal Area Network
Network of computers
in restricted (small) limited geographical area.
Whole network confines to single site.
Within an office, one organisation, campus.
2/2/2014
Dr.SAJEEVE VP
17

18. LAN- Components





File servers
Network operating system (software)
PC, W. Stns, nodes-(computers)
Network interface cards
Cabling / wireless connectivity
2/2/2014
Dr.SAJEEVE VP
18

19. 3. Network types- Based on statusNetwork Architectureorganisation of networks
Client – server (main-sub)
one main computer serving the nodes
several nodes needing permission to access
Peer-to peer (equal status)
All computers are of same status
having equal access to any other.
no permission needed
2/2/2014
Dr.SAJEEVE VP
19

20. LAN-WAN Comparison
1.
2.
3.
4.
5.
WAN
Wider area
Aim- Communication
External comunication link
Hired services from third
party- ISP
Interruption frequent
LAN
4.
Small area
Aim-resource sharing
Only internal cables
Owned
1.
Little interruption
1.
2.
3.
2.
Data error chance more
3.
7.
More devices required
4.
7. 2/2/2014 link several LANs Dr.SAJEEVE VP
May
6.
Small chance
Less devices
May be linked to WAN
20

21. What decides LAN-WAN ?
1.
2.
3.
4.
3 computers / 100 computers
WAN needs to have many LANS
One computer in India connected to another
in the USA- WAN OR LAN?
Two computers in the same lab connected
through internet.
2/2/2014
Dr.SAJEEVE VP
21

22. 4. Network – types- Based on Purpose
A.
Storage Area Network (SAN)
centrally managed storage
1. Network Attached Storage (NAS)
A dedicated shared storage
File servers-large capacity to store
Permit nodes to share
2. Direct Attached Storage (DAS)
Storage attached to a single server.
2/2/2014
Dr.SAJEEVE VP
22

23. 5. Other Network – types- Based on Purpose
Based on mode of connection
Wireless and wired
Global and national
Information super Highway
global networking
all digitally deliverable services.
2/2/2014
Dr.SAJEEVE VP
23

24. Network devices
1.
2.
3.
4.
5.
6.
Network Interface Card
Front end processor specialise in extnl. com
Multiplexer-routing multiple requests.
MODEM- wifi
Communication Channels-Cables/ Cell/tower/Satellite
Remote access devices
1.
2.
3.
4.
5.
Hub- connecting link for LANs
Bridge,
Repeater- strenthen- link if obstacles
Router –processor-MAC addresses in NICs
Switches-many ports- IP address
2/2/2014
Dr.SAJEEVE VP
24

25. HUB
1.
2.
3.
4.
5.
6.
7.
8.
A hardware device (include no s/w)
Common linking point
Usually connects two or more LANs
Does not read addresses but
Simply passes data without screening
Flooding- sending all to all nodes other than
sender- so more jam.
Junction point for LANs
Usually used in a campus to connect to LANs
2/2/2014
Dr.SAJEEVE VP
25

26. Gateways
1.
2.
3.
4.
5.
6.
7.
A hardware device (include no s/w)
Entrance to a network
Usually connects two or more LANs
Does not read addresses but
Simply passes data without screening
Flooding- sending all to all nodes other than
sender- so more jam.
No data management capacity unlike routers
or switches
2/2/2014
Dr.SAJEEVE VP
26

27. Bridge
1.
2.
3.
4.
5.
6.
7.
8.
Connects two n/w (LANs or WANs)
Reads the destination address
Sends the data only to the addressee
So less jam
Screens by destination address
No floodingJunction point for LANs
Usually used in different n/ws
2/2/2014
Dr.SAJEEVE VP
27

28. Router
1.
2.
3.
4.
5.
6.
7.
8.
9.
Connects two or more n/ws
Of different protocols
Programmable computer
Reads the destination by MAC address
Sends the data only to the addressee
No flooding-less jam
Reads data inside the packets
So programmable
Allow or not access certain data video/aud.
2/2/2014
Dr.SAJEEVE VP
28

29. Switch
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Connects two or more n/ws
Of different protocols
Many ports
Programmable computer
Reads the destination by MAC address
Sends the data only to the addressee
No flooding-less jam
Reads data inside the packets
So programmable
Allow or not- access certain data video/aud.
2/2/2014
Dr.SAJEEVE VP
29

30. differences
Respect
HUB Gtwys
Bridge
RutrSwitch
Read address
different protocols
Many ports
Programmable compu
Reads MAC address
IP ADDRESS
Addressee ONLY
Fooding / jam
Read inside packets
Programmable
Data screening.
N
N
N
N
N
N
N
Y
N
N
N
Y
N
N
N
N
N
Y
N
N
N
N
Y Y
YY
NY
YY
YY
NY
YY
NN
YY
YY
YY
2/2/2014
Desti
N
N
N
N
N
N
Y
N
N
N
Dr.SAJEEVE VP
30