Types of Network Topology
Types of Network Topology
Network topology refers to the configuration of a
network that includes nodes and connecting lines via sender and receiver. The
various network topologies are as follows:
Ø Point to
Point Topology
Ø Mesh
Topology
Ø Star
Topology
Ø Bus
Topology
Ø Ring
Topology
Ø Tree
Topology
Ø Hybrid
Topology
Point to Point
Topology
Point-to-Point Topology is a type
of topology which focuses on the sender and receiver's working. It is the most
basic form of communication between two nodes, one of which is the sender and
the other the receiver. High bandwidth is provided by point-to-point
connections.
Point to Point Topology
Mesh Topology
A mesh topology is a network
configuration in which each computer and network device is linked to the
others. Most communications can be dispersed using this topology even if one of
the connections fails. It is a wireless network topology that is widely used.
The diagram below depicts a simple computer configuration on a network with a
mesh design.
Figure 1: Each device is connected to the others
via dedicated channels. These channels are referred to as links.
If a N number of devices are connected together in
a mesh topology, the total number of ports required by each device is N-1.
Because there are 5 devices connected in Figure 1, the total number of ports
required by each device is 4. The total number of necessary ports is N * (N-1).
If N devices are connected in a mesh topology, then
the total number of dedicated links necessary to connect them is NC2, i.e.
N(N-1)/2. Because there are 5 devices linked in Figure 1, the total number of
links required is 5*4/2.
There are two types of Mesh topologies which are
mentioned below:
1.
Fully-connected Mesh Topology
2.
Partially-connected Mesh Topology
1. Full Mesh Topology:
All
the nodes within the network are connected with every other. If there are n
number of nodes are connected during a network transmission, each node will
have an n-1 number of connections.
2. Partial Mesh Topology:
The
partial mesh is more practical as compared to the full mesh. In a partially
connected mesh, all the nodes aren't necessary to be connected with one another
during a network.
Some
of the advantages and disadvantages of mesh topology connection are given below:
Advantages of mesh topology:
The following are some of the
advantages or benefits of mesh topology:
Ø Communication
is very fast between the nodes.
Ø Mesh
Topology is robust.
Ø The fault
is diagnosed easily. Data is reliable because data is transferred among the
devices through dedicated channels or links.
Ø Provides
security and privacy.
Ø High-level traffic management of mesh topology
Ø Failure of one single device does not affect the
network
Ø Data transmission consistency
Disadvantages of mesh topology:
Ø Installation
and configuration are difficult.
Ø The cost
of cables is high as bulk wiring is required, hence suitable for less number of
devices.
Ø The cost
of maintenance is high.
Ø Time-consuming
to build and maintain
Ø High cost
Ø Latency
issues
Ø Increased
workload in each node
The
internet backbone, which connects different internet service providers to one
another via unique channels, is a typical example of a mesh topology.
Additionally, a plane navigation systems and military communication systems use
this architecture.
See
the Mesh Topology advantages and disadvantages for more details.
Star Topology
In
a star topology, a cable connects each device to a single hub. All other nodes
are connected to this hub, which serves as the core node. The hub may have a
passive nature, meaning that it is not intelligent, like broadcasting devices,
but it may also be intelligent and known as an active hub. Repeaters are
present in active hubs. Computer connections are made using coaxial or RJ-45
wires. Many well-known Ethernet LAN protocols, such as CD (Collision Detection)
and CSMA (Carrier Sense Multiple Access), are employed in the Star Topology
Advantages of Star Topology
Ø Less damage in case of a single computer failure as
it does not affect the entire network
Ø High Fault Tolerance
Ø Connecting several Types of Devices
Ø Lower possibility of Data Collision
Ø Avoids point-to-point connections
Ø Each
device requires only 1 port i.e. to connect to the hub, therefore the total
number of ports required is N.
Ø Star
topology is cost-effective as it uses inexpensive coaxial cable.
Disadvantages of Star Topology
Ø If the concentrator (hub) on which the whole
topology relies fails, the whole system will crash down.
Ø The cost of installation is high.
Ø Performance is based on the single concentrator
i.e. hub.
Ø More
cables are required to be connected because each computer individually connects
to the central server
Ø Single
point of failure in case the server gets down.
A local area network (LAN) in
an office, where all computers are connected to a central hub, is a typical
example of a star topology. In wireless networks where every device is linked
to a wireless access point, this topology is additionally used.
Read the Star Topology's
advantages and disadvantages for more details.
Bus Topology
Every computer and network device in a bus topology
network is connected to a single cable. It has two directions. It is a
multiple-point connection and a non-robust topology since the topology crashes
if the backbone fails. LAN Ethernet connections using Bus Topology adhere to a
number of MAC (Media Access Control) protocols, including TDMA, Pure Aloha,
CDMA, Slotted Aloha, etc.
Figure 3: A bus topology with shared
backbone cable. The nodes are connected to the channel via drop lines.
Advantages of
Bus Topology
Ø It is easy to connect a device to the network
Ø It is cheaper than other network options
Ø The failure of one station does not affect the rest
of the network
Ø No hubs or switches are required
Ø Extensions can be made to the network
Ø Multiple nodes can be installed without difficulty
Ø Multiple peripherals can be supported through bus
topology
Ø CSMA is the most common method for this type of topology.
Ø Bus
topology is familiar technology as installation and troubleshooting techniques
are well known.
Disadvantages of
Bus Topology
Ø A bus topology is quite simpler, but still, it
requires a lot of cabling
Ø Additional devices slow the network down
Ø Size limitations are always present
Ø Security options are limited with bus topology
Ø Maintenance costs are higher
Ø A break in the backbone can cause an entire network
to collapse
Ø The quality of the data is placed at-risk on large bus topology setups
Ø Bus termination issues can lead to network issues
Ø Security
is very low.
Ø If
the network traffic is heavy, it increases collisions in the network. To avoid
this, various protocols are used in the MAC layer known as Pure Aloha, Slotted
Aloha, CSMA/CD, etc.
The Ethernet LAN, where all
devices are connected to a single coaxial cable or twisted pair cable, is a
typical example of a bus topology. Cable TV networks also make advantage of
this topology. See the Bus Topology advantages and disadvantages for more
details.
Ring Topology
It creates a ring connecting
devices with precisely two neighbouring devices in a ring topology. With a
large number of nodes, a ring topology requires a number of repeaters because,
in order to convey data to the last node in a ring topology with 100 nodes, the
data must first go via 99 nodes. Therefore, repeaters are utilized in the
network to prevent data loss.
Data flow is unidirectional, or
flows in only one direction, while dual ring topology, or having two links
between each Network Node, allows for bidirectional data flow. The workstations
communicate data using the Token Ring Passing protocol and an In-Ring Topology.
The most common access method of ring topology is
token passing.
Ø Token passing: It
is a network access method in which a token is passed from one node to another
node.
Ø Token: It
is a frame that circulates around the network.
Operations
of Ring Topology:
1.
One station, referred to as a monitor station, is
in charge of carrying out all operations.
2.
The token will move about in the ring when there is
no station sending data.
3.
The station must possess the token in order to
transmit the data. The token must be made available for use by other stations
after the transmission is over.
4.
There are two different methods for releasing
tokens: Early token release releases the token immediately after data
transmission, and Delayed token release distributes the token once the receiver
acknowledges receipt of the data.
Advantages of Ring Topology
Ø The
data transmission is high-speed.
Ø
The possibility of collision is minimum in this
type of topology.
Ø
Cheap to install and expand.
Ø
It is less costly than a star topology.
Ø
because data passes around the network in one
direction, there are no network collisions
Ø adding
additional nodes has very little impact on bandwidth
Disadvantages of
Ring Topology
Ø if
any of the nodes fail, the ring is broken and data cannot be transmitted
Ø
it is difficult to troubleshoot a ring network
topology
Ø
because all nodes are wired together, the network
must be temporarily stopped to add additional nodes
Ø
The failure of a single node in the network can
cause the entire network to fail.
Ø
Troubleshooting is difficult in this topology.
Ø
The addition of stations in between or the removal
of stations can disturb the whole topology.
Ø Less
secure.
Read Ring Topology's
advantages and disadvantages for more details.
Tree
Topology
The Star topology is a
subset of this topology. The data flow in this topology is hierarchical.
Protocols like DHCP and SAC (Standard Automatic Configuration) are employed in
tree topology.
A tree topology is sometimes referred to as a
star bus topology in computer networks. Both a bus topology and a star topology
are represented in it. The centre nodes of two star networks are connected to
one another in the example network diagram of a tree topology that is shown
below.
In the diagram, the two-star topology networks
would be unable to interact with one another if the main cable (trunk)
connecting them failed. However, communication between computers on the same
star topology would still be possible.
In Figure: shows how the different subsidiary hubs are connected to the
main hub, that contains the repeater. Both top and bottom directions—from the
central hub to the secondary hub and then to the devices—or bottom and top—from
the devices to the secondary hub and then to the central hub—are possible for
this data flow. It is a multiple-point connection and a non-robust topology
since the topology crashes if the backbone fails.
Advantages of Tree Topology
Ø
It reduces the distance that the
signal has to cover between the devices by allowing more devices to be
connected to a single central hub.
Ø
It enables the network to grow more
separate and prioritize traffic from other computers.
Ø
We can add new devices to the
existing network.
Ø
In a tree topology, errors detection
and correction are simple.
Disadvantages of Tree Topology
Ø
If the central hub gets fails, the
entire system fails.
Ø
The cost is high because of the
cabling.
Ø
If new devices are added, it becomes
difficult to reconfigure.
A common
example of a tree topology is the hierarchy in a large organization. At the top
of the tree is the CEO, who is connected to the different departments or
divisions (child nodes) of the company. Each department has its own hierarchy,
with managers overseeing different teams (grandchild nodes). The team members
(leaf nodes) are at the bottom of the hierarchy, connected to their respective
managers and departments.
More details can be read according to the
Advantages and Disadvantages of Tree Topology.
Hybrid Topology
This
topological technology includes all of the various kinds of topologies
discussed above. When nodes are free to take any shape, hybrid topology is
used. It indicates that they can be individual topologies like Ring or Star
topology or a combination of the various sorts of topologies shown above. Each
separate topology employs the previously mentioned protocol.
In figure: The above figure shows
the structure of the Hybrid topology. As seen it contains a combination of all
different types of networks.
Advantages of Hybrid Topology
Ø This topology is very flexible.
Ø The size of the network can be easily
expanded by adding new devices.
Disadvantages of Hybrid Topology
Ø It is challenging to design the architecture of
the Hybrid Network.
Ø Hubs used in this topology are very
expensive.
Ø The infrastructure cost is very high as a
hybrid network requires a lot of cabling and network devices.
A common example of a hybrid topology is
a university campus network. The network may have a backbone of a star
topology, with each building connected to the backbone through a switch or
router. Within each building, there may be a bus or ring topology connecting
the different rooms and offices. The wireless access points also create a mesh
topology for wireless devices. This hybrid topology allows for efficient
communication between different buildings while providing flexibility and
redundancy within each building.
More details can be read under the
Advantages and Disadvantages of Hybrid Topology.
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