COMPUTER NETWORK(Introduction, classification)NETWORK TOPOLOGY.pptx

COMPUTER NETWORK
HALIMA ZANNATI TARIN
ID- 2023-1-70-054
SECTION-01
FALL-23

COURSE OUTLINE
Computer Network Introduction, Motivation, Classification: LAN, MAN, WAN
Network Topology
Definition, Classification: BUS, TREE, STAR, RING, MESH,
HYBRID
Background of Network When there was no network
Motivation Resource Sharing
Resource
Hardware
Software
Data/Information

DEFINITION
 When a number of computers or
devices are interconnected in a single
communication system
 Growth of number & power of
computers is driving need for
interconnection
 Also seeing rapid integration of voice,
data, image & video technologies

Network Components
A network consists of the following
components:
 Computers/other devices (mobile, tab…)
 Network interface cards
 Peripheral devices
 Networking media
 Network devices

CLASSIFICATION
Depending upon the area coverage:
Local Area Network (LAN)
Metropolitan Area network (MAN)
Wide Area Network (WAN)

LAN
 smaller scope
 Building or small campus
 usually owned by same organization
as attached devices
 data rates much higher
 switched LANs, eg Ethernet
 wireless LANs

LAN
LANs make it possible for businesses that
use computer technology to locally share files and printers
efficiently, and make internal communications possible.
A good example of this technology is
“Computer Lab”.
They tie data, local communications, and
computing equipment together.

LAN
Some common LAN technologies are:
 Ethernet
 Token Ring
 FDDI

MAN
Metropolitan Area Network
A MAN is a network that spans a
metropolitan area such as a city or suburban
area.
A MAN usually consists of two or more LANs
in a common geographic area.
For example, a bank with multiple branches
may utilize a MAN.

MAN
Middle ground between LAN and WAN
private or public network
high speed
large area
Typically, a service provider is used to
connect two or more LAN sites using private
communication lines or optical services.
A MAN can also be created using wireless
bridge technology by beaming signals across
public areas.

WAN
Network of the networks (Internet)
 Span a large geographical area
 Rely in part on common carrier circuits
 Alternative technologies used include:
 circuit switching
 packet switching
 frame relay
 Asynchronous Transfer Mode (ATM)

WAN
WANs are designed to do the following:
Operate over a large geographically separated
areas
Allow users to have real-time communication
capabilities with other users
Provide full-time remote resources connected to
local services
Provide e-mail, World Wide Web, file transfer, and
e-commerce services

WAN
Some common WAN technologies are:
Modems
Integrated Services Digital Network (ISDN)
Digital Subscriber Line (DSL)
Frame Relay
US (T) and Europe (E) Carrier Series – T1, E1, T3, E3
Synchronous Optical Network (SONET)

COMPUTER NETWORK(Introduction, classification)NETWORK TOPOLOGY.pptx

STORAGEAREA NETWORK
 A SAN is a dedicated, high-performance network used to
move data between servers and storage resources.
 Because it is a separate, dedicated network,
 it avoids any traffic conflict between clients and servers.
 SAN technology allows high-speed server- to-storage,
storage-to-storage, or server-to- server connectivity

STORAGEAREA NETWORK
This method uses a separate network infrastructure that relieves any problems
associated with existing network connectivity.
SANs offer the following features:
 Performance – SANs enable concurrent access of disk or tape arrays by two or
more servers at high speeds, providing enhanced system performance.
 Availability – SANs have disaster tolerance built in, because data can be
mirrored using a SAN up to 10 kilometers (km) or 6.2 miles away.
 Scalability – Like a LAN/WAN, it can use a variety of technologies. This allows
easy relocation of backup data, operations, file migration, and data replication
between systems.

Virtual Private Network (VPN)
 A VPN is a private network that is constructed within
a public network infrastructure such as the global
Internet.
 Using VPN, a telecommuter can access the network
of the company headquarters through the Internet
by building a secure tunnel between the
telecommuter’s PC and a VPN router in the
headquarters.

Virtual Private Network (VPN)
Benefits of VPN:
A VPN is a service that offers secure, reliable connectivity over a shared
public network infrastructure such as the Internet.
VPNs maintain the same security and management policies as a private
network.
They are the most cost-effective method of establishing a point-to-
point connection between remote users and an enterprise customer's
network.

Intranet
 One common configuration of a LAN is an Intranet.
 Intranet Web servers differ from public Web servers in that the public
must have the proper permissions and passwords to access the
Intranet of an organization.
 Intranets are designed to permit access by users who have access
privileges to the internal LAN of the organization.
 Within an Intranet, Web servers are installed in the network.
 Browser technology is used as the common front end to access
information such as financial data or graphical, text-based data stored
on those servers.

Network Topology
The geometric structure of the interconnections among the
participating computers and devices in the network.

Classification
BUS
Tree
Star
Mesh
Ring
Hybrid

BUS
Architecture:
Each machine is connected to a single
cable called drop cable through some kind of
connector Tap.
Each computer or server is connected to
the single common shared bus cable, called
the backbone of the bus topology network.
A terminator is required at each end of the
bus cable to prevent the signal from
bouncing back and forth on the bus cable.

BUS
 used with multipoint medium
 transmission propagates throughout medium
bi- directionally
 heard by all stations
 full duplex connection between station and
tap
 allows for transmission and reception
 need to regulate transmission
to avoid collisions and hogging
 terminator absorbs frames at end of medium

TREE
 The tree topology is a generalization of the bus
topology.
 The transmission medium is a branching cable with no
closed loops.
 The tree layout begins at a point known as the
headend or root.
 One or more cables start at the headend, and each of
these may have branches.
 The branches in turn may have additional branches to
allow quite complex layouts.
 Again, a transmission from any station propagates
throughout the medium and can be received by all
other stations.

Ring
 A closed loop of repeaters joined by point to point links,
called the backbone.
 Receive data on one link & retransmit on another
o links unidirectional
o stations attach to repeaters
 Data in frames
circulate past all stations
destination recognizes address and copies frame
frame circulates back to source where it is removed
media access control determines when a station can
insert frame

STAR
 In the star LAN topology, each station is directly connected to a common central
node.
 Typically, each station attaches to a central node via two point- to-point links,
one for transmission and one for reception.
 In general, there are two alternatives for the operation of
the central node.
 One approach is for the central node to operate in a broadcast fashion.
o A transmission of a frame from one station to the node is retransmitted on all of the
outgoing links.
o In this case, although the arrangement is physically a star, it is logically a bus: A
transmission from any station is received by all other stations, and only one station at a
time may successfully transmit.
o In this case, the central element is referred to as a hub.

STAR
 Another approach is for the
central node to act as a
frame-switching device.
 An incoming frame is
buffered in the node and
then retransmitted on an
outgoing link to the
destination station.

MESH
All the nodes are directly connected to all other nodes.
 Highly reliable with alternative paths between any
pair of hosts
 Very good for short distance communication
 The physical fully connected mesh topology is
generally too
 costly and complex for practical networks
 Not feasible for long haul communication.
 Fully connected mesh topology
 The number of connections in a full mesh = n(n - 1) / 2

COMPUTER NETWORK(Introduction, classification)NETWORK TOPOLOGY.pptx

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