Network
topology and its types:
Definition
1:
The physical arrangement of connected devices in a
network is called network topology;
Definition
1:
The way in which computer and other devices are connected
is called network topology.
Types
of network topology:
·
Star topology
·
Ring topology
·
Bus topology
·
Mesh topology
·
Hybrid topology
Star
topology:
In the computer networking world the most common used
topology in LAN is the star topology.
All the computer in star topology are connected to
central devices like hub, switch or router using the twisted pair cables.
In star topology, the sending computer sends the data to
hub. the hub sends data to receiving computer. Each computer in star network
communicates with a central hub.
Star topology can be implemented in home, offices, or
even in a building .
Advantages
of star topology:
·
It is easy to install and maintain the
network.
·
Adding or removing computers can be done
without disturbing the network.
·
Easy to detect faults.
·
Failure of computer or link does not effect
the whole network.
Disadvantages
of star topology:
·
Failure of central hub suffers the entire
network.
·
It requires large number of cables to connect
computers.
·
It is more expensive.
Ring
topology:
Each computer is connected to the next computer while the
last one is connected to the first one and making ring.
Messages that are transmitted travel around the ring
until they reach the destination computer.
In ring topology, every
computer is connected to next computer .each computer receives message from the
previous computer and transmits it to the next computer. the message flows in
one direction.
Advantages
of ring topology:
·
It is less expensive than star topology.
·
Every computer has equal access to the
network.
·
Perform better than a star network under
heavy network load.
·
There is no need of server to control the
connectivity between computers.
Disadvantages
of ring topology:
·
Failure of one node brings the whole network
down
·
Error detection and network administration
becomes difficult.
·
Moves, adds and changes of devices can
effects the network
·
Network is highly dependent on wire which
connects different devices.
Bus
topology:
Bus topology is that in which all the nodes (computer as
well as servers) are connect to the single cable(called bus).
This central cable is the backbone of the network and is
known as bus.
Every workstation communicates with the other devices
through this BUS. signal from the source is broadcasted and it travels to all
workstations connected to bus cable. although the message is broadcasted but
only the intended recipient ,whose MAC address or IP address matches. accepts it. if the MAC/IP
address of machine doesn’t matches with the intended address, machine discards
the signal.
A collision can occur in bus topology if two computer transmit
data at the same time .
Advantages
of BUS topology:
·
It is very easy and simple to use.
·
It requires short amount of cables
·
More computer can easily be connected without
disturbing the network .
·
If one node fails, it does not effect the
whole network.
Disadvantages
of bus topology:
·
Entire network goes down if main cable fails.
·
Difficult to detect problem if the entire
network shuts down.
·
Not suitable for network with heavy load.
Mesh
topology:
Mesh means net in this topology, every computer is
directly connected to every other computer ,multiple links exist among network
computers, in mesh network message sent can take any of server possible paths
form sources to destination this topology is very expensive as it requires more
connection mesh network is come only used in very less networks
Advantages
of mesh topology:
·
Due to multiple links mesh network can work
very fine even under heavy load.
·
Troubleshooting of mesh network is easy as
compare to other network.
·
On this network it is easy to add new computer
without disturbing other computer
·
Disadvantages of mesh top0logy:
·
Cable cost is too high due to multiple links
·
It is very difficult to maintain this network
due to large number of computer
Hybrid
mesh:
In hybrid mesh total links are less than in (n-1)/2 for
”n” computers each computer is not directly connected with each other computer
in the network, if for example the total number of computers “n” is 6 in 3 or 9
links instead of 15 then such a network will be a hybrid mesh.
Advantages:
·
Mesh network has high fault tolerance due to
multiple links
·
Due to multiple links mesh network can work
fine even under severe loads
·
Troubleshooting of mesh network is easy as
compared to other network.
Disadvantages:
·
Cable cost is too high due to multiple links
this cable cost may even be more than a star network in case of true mesh
network among a large number of computers.
·
It is also very difficult to maintain a true
mesh for a large number of computers
