NETWORK
NETWORK
By By
Bhupendra Ratha, Lecturer Bhupendra Ratha, Lecturer
School of Library and Information Science School of Library and Information Science
Devi Ahilya University, Indore Devi Ahilya University, Indore
Email:
Email: bhu261@gmail.combhu261@gmail.com
Network
Network
A network is a group of devices (Nodes) connected by media links. A node can be a
computer, printer or any other device capable of sending and receiving data generated by other nodes on the network.
In other words, a group of computer and associated peripherals connected by a
communication channel capable of sharing files and other resources between several users is
called network.
Types of Network
Types of Network
Types of Network
LAN
(Local Area Network)
MAN
(Metropolitan Area Network)
WAN
(Wide Area Network)
It is a campus, office or organization
Network extended over An entire city
Network extended over entire globe
LAN
LAN
A LAN can be as simple as two PCs and A LAN can be as simple as two PCs and printer in ones home, office or it can be printer in ones home, office or it can be
throughout a company and include voice, and throughout a company and include voice, and video peripherals. At present LAN size is
video peripherals. At present LAN size is restricted to one kilometers.
restricted to one kilometers.
LAN
LAN
A office
Features of LAN
Features of LAN
LAN uses NOS (Networking Operating System) , which LAN uses NOS (Networking Operating System) , which ties all the components together and makes operations ties all the components together and makes operations transparent to user.
transparent to user.
LANs are wholly owned by an organization.LANs are wholly owned by an organization.
LAN is a system of interlinked personal computers.LAN is a system of interlinked personal computers.
A LAN works on the principle of load sharing because the A LAN works on the principle of load sharing because the program to be executed is down loaded into the personal program to be executed is down loaded into the personal computer memory.
computer memory.
LAN has a very limited geographic range normally less LAN has a very limited geographic range normally less than
than 1 1 km.km.
Advantage of LAN
Advantage of LAN
It permits sharing of expensive hardware'sIt permits sharing of expensive hardware's
LAN improves the productivity, because information storage, LAN improves the productivity, because information storage, processing and retrieval and other functionally can be
processing and retrieval and other functionally can be improved.
improved.
It provide cost effective multiIt provide cost effective multi--user computer environment.user computer environment.
It provide high transmission rate to accommodate the needs of It provide high transmission rate to accommodate the needs of both user and equipment.
both user and equipment.
Error rate is very less because inError rate is very less because in--built method of detecting and built method of detecting and compensating for systems error is implied.
compensating for systems error is implied.
It allows file/record locking.It allows file/record locking.
Disadvantage of LAN
Disadvantage of LAN
Installation and reconfiguration always Installation and reconfiguration always requires technical & skilled man power.
requires technical & skilled man power.
Due to sharing of resources, sometime Due to sharing of resources, sometime operational speed may be slow down.
operational speed may be slow down.
Insufficient knowledge of network Insufficient knowledge of network
administrator creates improper authorization administrator creates improper authorization and security problem.
and security problem.
Problem of password hacking.Problem of password hacking.
MAN
MAN
A network is bigger than LAN but smaller than A network is bigger than LAN but smaller than WAN, “Multiple LANs that are connected
WAN, “Multiple LANs that are connected within the same city to form a citywide
within the same city to form a citywide
network for a specific government or industry network for a specific government or industry using a high speed backbone” It is known as using a high speed backbone” It is known as MAN.
MAN.
MAN
MAN
Indore
Network operated By Public/Private
company
Features of MAN
Features of MAN
MAN is a network designed to extend over an MAN is a network designed to extend over an entire city.
entire city.
MAN includes different private LANs MAN includes different private LANs connected through cable and router or connected through cable and router or gateway.
gateway.
It is bigger than LAN but smaller than WAN.It is bigger than LAN but smaller than WAN.
FDDI technology is the best suited for MAN.FDDI technology is the best suited for MAN.
Advantage of MAN
Advantage of MAN
Any company can connect all its branches Any company can connect all its branches existing in the same city.
existing in the same city.
It is economical because sharing of costly It is economical because sharing of costly resources for all branches of a company.
resources for all branches of a company.
Disadvantage of MAN
Disadvantage of MAN
Network installation is difficult and required Network installation is difficult and required skilled persons.
skilled persons.
Installation cost is very much.Installation cost is very much.
WAN
WAN
A WAN is a network that connect users across A WAN is a network that connect users across large distances, often crossing the geographical large distances, often crossing the geographical boundaries of cities, states or Nations.
boundaries of cities, states or Nations.
WAN
WAN
Earth
Features of WAN
Features of WAN
In this network, computers and small networks In this network, computers and small networks are inter
are inter--connected without cables but with the connected without cables but with the help of telephone lines, microwave and
help of telephone lines, microwave and satellite links.
satellite links.
WAN can be implemented with the help of WAN can be implemented with the help of private networks as well as public networks.
private networks as well as public networks.
It is the very longIt is the very long--distance communication distance communication network.
network.
Advantage of WAN
Advantage of WAN
WAN has no limit of area, so it is world wide WAN has no limit of area, so it is world wide network.
network.
Multi country’s organizations have facility to form Multi country’s organizations have facility to form their global integrated network through WAN.
their global integrated network through WAN.
WAN support global markets and global business.WAN support global markets and global business.
For a network database, WAN allows users all over a For a network database, WAN allows users all over a network to access and update a single, consistent
network to access and update a single, consistent view of data.
view of data.
Disadvantage of WAN
Disadvantage of WAN
WAN is very big and complex network.WAN is very big and complex network.
It is slow in speed.It is slow in speed.
WAN is not very much secured means not WAN is not very much secured means not reliable.
reliable.
It is very costly because we have to pay every It is very costly because we have to pay every time for transferring data.
time for transferring data.
Very much dependency on the third party Very much dependency on the third party because it is public network.
because it is public network.
Difference between
Difference between
LAN, MAN & WAN
LAN, MAN & WAN
Point of view
Point of view LANLAN MANMAN WANWAN
Range
Range 1km1km CityCity UnlimitedUnlimited
Authority Authority PersonalPersonal Company or Company or
Organizations Organizations
No authority No authority
Cost
Cost NormalNormal MediumMedium Very muchVery much Connectivity
Connectivity Device
Device
Cable media
Cable media Cable media andCable media and Telephone lines Telephone lines
Telephone lines, Telephone lines, microwave and microwave and Satellite
Satellite
Speed
Speed 0.1 to 100mbps0.1 to 100mbps 1 to 1mbps1 to 1mbps 1800 to 9600 bits 1800 to 9600 bits per second
per second
Accuracy
Accuracy Very GoodVery Good GoodGood MediumMedium
Network Topology
Network Topology
A topology defines the arrangement of nodes, A topology defines the arrangement of nodes, cables and connectivity devices that make up cables and connectivity devices that make up the network.
the network.
In other words we can say topology is the In other words we can say topology is the
geometric arrangement of workstations and the geometric arrangement of workstations and the links among them.
links among them.
Parameters to analyses the Topology
Parameters to analyses the Topology
There are certain parameters, to help us select the best There are certain parameters, to help us select the best
topology for our situation and they are;
topology for our situation and they are;
ApplicationApplication
ComplexityComplexity
PerformancePerformance
System overheadSystem overhead
VulnerabilityVulnerability
ExpandabilityExpandability
Application
Application
It shows in what size installation is the topology most It shows in what size installation is the topology most appropriate
appropriate..
Complexity
Complexity
It shows, how technically complex is the topology ? It shows, how technically complex is the topology ?
Performance
Performance
It shows, how much of a traffic load can the It shows, how much of a traffic load can the system support
system support
System overhead
System overhead
It shows, what is the comparative price for It shows, what is the comparative price for excess capability.
excess capability.
Vulnerability
Vulnerability
It shows, how susceptible in the topology to It shows, how susceptible in the topology to failure and damage.
failure and damage.
Expandability Expandability
When we are ready to extend the LAN, how When we are ready to extend the LAN, how easily can be topology accommodate
easily can be topology accommodate
additional workstations and cover larger additional workstations and cover larger distances ?
distances ?
Types of Topology
Types of Topology
Topology can be divide in two basic type;Topology can be divide in two basic type;
1.
1. Physical topologyPhysical topology
2.
2. Logical topologyLogical topology
Physical Topology
Physical Topology
It describes the actual layout of the network It describes the actual layout of the network transmission media, means the way of
transmission media, means the way of networks looks.
networks looks.
Logical Topology
Logical Topology
It describes the logical pathway a signal It describes the logical pathway a signal
follows as it passes among the network nodes, follows as it passes among the network nodes, means the way the data passes among the
means the way the data passes among the nodes.
nodes.
The most common types of Network
The most common types of Network
Topology
Topology
Bus TopologyBus Topology
Ring TopologyRing Topology
Star TopologyStar Topology
Tree TopologyTree Topology
Mesh TopologyMesh Topology
Token ring TopologyToken ring Topology
Bus Topology
Bus Topology
Drop lines/Interface units
Terminator Terminator
Characteristics of Bus Topology
Characteristics of Bus Topology
A bus topology is one in which all device A bus topology is one in which all device
connect to common shared cable (backbone) connect to common shared cable (backbone) through interface units/drop lines and taps.
through interface units/drop lines and taps.
This topology is used in traditional data This topology is used in traditional data
communication networks where the host at one communication networks where the host at one end of the bus communicate with several
end of the bus communicate with several terminals attached along its length.
terminals attached along its length.
Cont…
Cont…
Special connector called terminator must be Special connector called terminator must be placed at the end of the backbone cable to placed at the end of the backbone cable to prevent signals from reflecting back on the prevent signals from reflecting back on the cable and causing interference.
cable and causing interference.
Bus configuration is known as multiBus configuration is known as multi--drop line.drop line.
Advantage of Bus Topology
Advantage of Bus Topology
Installation is very easy because it is a single cable Installation is very easy because it is a single cable network.
network.
It uses less cabling than any other topology.It uses less cabling than any other topology.
Additional nodes can be connected to an existing bus Additional nodes can be connected to an existing bus network at any point along its length.
network at any point along its length.
It is a resilient (flexible) architecture means simple It is a resilient (flexible) architecture means simple and reliable .
and reliable .
It is very economical.It is very economical.
Disadvantage of Bus Topology
Disadvantage of Bus Topology
Difficult reconfiguration and fault isolation.Difficult reconfiguration and fault isolation.
All the nodes are directly connected to central All the nodes are directly connected to central cable and nodes have to decide which uses the cable and nodes have to decide which uses the network first.
network first.
Entire network shutdown if there is a failure in Entire network shutdown if there is a failure in the backbone.
the backbone.
The damage area reflects signals back in the The damage area reflects signals back in the direction of origin, creating noise in both
direction of origin, creating noise in both directions.
directions.
Ring Topology
Ring Topology
Features of Ring Topology
Features of Ring Topology
Ring topology are wired in a circle, each node is connected to Ring topology are wired in a circle, each node is connected to its neighbors on either side.
its neighbors on either side.
Data signals passes around the ring in one direction.Data signals passes around the ring in one direction.
Each device incorporates a receiver and a transmitter, and Each device incorporates a receiver and a transmitter, and
serves as a repeater that passes the signal on to the next device serves as a repeater that passes the signal on to the next device in the ring.
in the ring.
Ring topologies are quite rare.Ring topologies are quite rare.
No routing capability is required as messages automatically No routing capability is required as messages automatically travel to the next workstation on the network.
travel to the next workstation on the network.
Advantage of Ring Topology
Advantage of Ring Topology
A ring relatively easy to install and reconfigure.A ring relatively easy to install and reconfigure.
Less cabling involved in a ring topology comparable Less cabling involved in a ring topology comparable to that of bus and is small relative to other.
to that of bus and is small relative to other.
Each device is linked only to its immediate neighbors Each device is linked only to its immediate neighbors so to add or delete a device requires moving only two so to add or delete a device requires moving only two connections.
connections.
It is good for small number of workstations operating It is good for small number of workstations operating at high speeds over short distances are to be
at high speeds over short distances are to be connected.
connected.
Disadvantage of Ring Topology
Disadvantage of Ring Topology
A node failure causes entire network failure.A node failure causes entire network failure.
A ring requires relatively complex hardware to A ring requires relatively complex hardware to implement.
implement.
The failure of one node will affect all others The failure of one node will affect all others has serious problem for fault diagnosis.
has serious problem for fault diagnosis.
Topology affects the access protocol.Topology affects the access protocol.
Star Topology
Star Topology
Features of Star Topology
Features of Star Topology
It require that all devices connect to a central hub or It require that all devices connect to a central hub or wiring concentrator through a dedicated point to point.
wiring concentrator through a dedicated point to point.
The hub receives signals from the other network devices The hub receives signals from the other network devices and routs the signals to the proper destinations.
and routs the signals to the proper destinations.
Nodes do not have to make routing decisions, as all Nodes do not have to make routing decisions, as all
communications must pass through the central hub before communications must pass through the central hub before going to their destinations.
going to their destinations.
The size and capacity of the network is the depend on the The size and capacity of the network is the depend on the central hub.
central hub.
Advantage of Star Topology
Advantage of Star Topology
Each device needs only one link and one I/O Each device needs only one link and one I/O port to connect it to any number of others.
port to connect it to any number of others.
It is easy to install and reconfigure.It is easy to install and reconfigure.
Robustness of network means if one link fails, Robustness of network means if one link fails, only that link is affected and all other links
only that link is affected and all other links remain active.
remain active.
Due to the above fact, fault identification and Due to the above fact, fault identification and fault isolation is very easy.
fault isolation is very easy.
Disadvantage of Star Topology
Disadvantage of Star Topology
Cabling is required very much.Cabling is required very much.
Difficult to expand the network.Difficult to expand the network.
If the central node in a star network fails the If the central node in a star network fails the entire network is rendered inoperable
entire network is rendered inoperable
Maintenance and installation problems can Maintenance and installation problems can increase costs considerably.
increase costs considerably.
Tree Topology
Tree Topology
Server Central/Primary node
Secondary hub
Features of Tree Topology
Features of Tree Topology
In tree , central hub is used to connect only In tree , central hub is used to connect only secondary hubs, not with all nodes.
secondary hubs, not with all nodes.
So nodes & devices are connected through the So nodes & devices are connected through the secondary hubs.
secondary hubs.
Normally the central hub of tree is an active Normally the central hub of tree is an active hub so it is able to filter & regenerate the
hub so it is able to filter & regenerate the signals
signals
Secondary hub may be active or passive.Secondary hub may be active or passive.
Advantage of Tree Topology
Advantage of Tree Topology
Tree network can be easily extended because Tree network can be easily extended because central hub has so many hubs.
central hub has so many hubs.
Network (or subNetwork (or sub--network) can be isolated and network) can be isolated and communication can be prioritized.
communication can be prioritized.
Due to the above fact time sensitive data will Due to the above fact time sensitive data will not have to wait for access to the network.
not have to wait for access to the network.
Disadvantage of Tree Topology
Disadvantage of Tree Topology
Tree topology has all the disadvantages of star Tree topology has all the disadvantages of star topology .
topology .
The subsection has dependence on the root The subsection has dependence on the root section.
section.
Bigger branches slow down the speed of Bigger branches slow down the speed of network.
network.
Mesh Topology
Mesh Topology
Features of Mesh Topology
Features of Mesh Topology
Every device has a dedicated point to point Every device has a dedicated point to point link to every other device.
link to every other device.
Mesh is really a hybrid model representing an Mesh is really a hybrid model representing an all channels topology.
all channels topology.
Every device on the network must have Every device on the network must have n
n--1 input/output ports.1 input/output ports.
Advantage of Mesh Topology
Advantage of Mesh Topology
It is very much fault tolerance capacity.It is very much fault tolerance capacity.
Privacy or security is very high, every message Privacy or security is very high, every message sent travels along a dedicated line only the
sent travels along a dedicated line only the intended recipient sees it.
intended recipient sees it.
Disadvantage of Mesh Topology
Disadvantage of Mesh Topology
Installation & reconfiguration is very difficult.Installation & reconfiguration is very difficult.
Extra workload to network administrator.Extra workload to network administrator.
It requires very much cabling & I/O ports.It requires very much cabling & I/O ports.
Extra wiring can be greater than the available Extra wiring can be greater than the available space can accommodate.
space can accommodate.
It is the most expansive network.It is the most expansive network.
Token Ring Topology
Token Ring Topology
Features of Token Ring Topology
Features of Token Ring Topology
In this topology, wired in a circular format but In this topology, wired in a circular format but all the node connected by the drop lines and T all the node connected by the drop lines and T-- shape tokens.
shape tokens.
In this topology all the nodes have only In this topology all the nodes have only receiver and transmitter not a repeater.
receiver and transmitter not a repeater.
Advantage of Token Ring Topology
Advantage of Token Ring Topology
A node failure causes entire network are not A node failure causes entire network are not failure.
failure.
No problems in fault diagnosis.No problems in fault diagnosis.
Privacy and accuracy in data transmission.Privacy and accuracy in data transmission.
Disadvantage of Token Ring Topology
Disadvantage of Token Ring Topology
A token ring is difficult to install and A token ring is difficult to install and reconfigure.
reconfigure.
Cabling is required very much.Cabling is required very much.
It does not allow direct traffic between It does not allow direct traffic between devices.
devices.
