what is topology in networking and their uses in practical life with example
A Network Topology is the arrangement with which computer systems or network devices are connected to each other. Topologies may define both physical and logical aspect of the network. Both logical and physical topologies could be same or different in a same network.
Point-to-Point
Point-to-point networks contains exactly two hosts such as computer, switches or routers, servers connected back to back using a single piece of cable. Often, the receiving end of one host is connected to sending end of the other and vice-versa.
If the hosts are connected point-to-point logically, then may have multiple intermediate devices. But the end hosts are unaware of underlying network and see each other as if they are connected directly.
Bus Topology
In case of Bus topology, all devices share single communication line or cable.Bus topology may have problem while multiple hosts sending data at the same time. Therefore, Bus topology either uses CSMA/CD ()technology or recognizes one host as Bus Master to solve the issue. It is one of the simple forms of networking where a failure of a device does not affect the other devices. But failure of the shared communication line can make all other devices stop functioning.
Both ends of the shared channel have line terminator. The data is sent in only one direction and as soon as it reaches the extreme end, the terminator removes the data from the line.
an example of bus topology is connecting two floors through a single line. Ethernet networks also use a bus topology. In a bus topology, one computer in the network works as a server and other computers behave as clients. The purpose of the server is to exchange data between client computers …
Star Topology
All hosts in Star topology are connected to a central device, known as hub device, using a point-to-point connection. That is, there exists a point to point connection between hosts and hub. The hub device can be any of the following:
Layer-1 device such as hub or repeater
Layer-2 device such as switch or bridge
Layer-3 device such as router or gateway
As in Bus topology, hub acts as single point of failure. If hub fails, connectivity of all hosts to all other hosts fails. Every communication between hosts, takes place through only the hub.Star topology is not expensive as to connect one more host, only one cable is required and configuration is simple.
So, we connect our laptops, tablet PCs and Smartphones to the Wireless Modem for accessing the Internet. Hence, all our devices connect to a single central device known as Hub. So, this is probably the best Example of Star Topology.
Ring Topology
In ring topology, each host machine connects to exactly two other machines, creating a circular network structure. When one host tries to communicate or send message to a host which is not adjacent to it, the data travels through all intermediate hosts. To connect one more host in the existing structure, the administrator may need only one more extra cable.
school campuses
Ring network topologies are most often found on school campuses, though some commercial organizations also use them. FDDI, SONET, or Token Ring technology are typically used. Data is transported bit by bit from each node until it reaches its destination.23-Oct-2017
Failure of any host results in failure of the whole ring.Thus, every connection in the ring is a point of failure. There are methods which employ one more backup ring.
However, one of the common example that still exists is SONET Rings. SONET stands for Synchronous Optical Networking. It uses Fiber Optic Cables for heavy load data transfers for long distances. You can simply think SONET to be Fiber Optic Cable Ring Topology.
Mesh Topology
In this type of topology, a host is connected to one or multiple hosts.This topology has hosts in point-to-point connection with every other host or may also have hosts which are in point-to-point connection to few hosts only.
Hosts in Mesh topology also work as relay for other hosts which do not have direct point-to-point links. Mesh technology comes into two types:
Full Mesh: All hosts have a point-to-point connection to every other host in the network. Thus for every new host n(n-1)/2 connections are required. It provides the most reliable network structure among all network topologies.
Partially Mesh: Not all hosts have point-to-point connection to every other host. Hosts connect to each other in some arbitrarily fashion. This topology exists where we need to provide reliability to some hosts out of all.
Mesh topology is a type of networking where all nodes cooperate to distribute data amongst each other. This topology was originally developed 30+ years ago for military applications, but today, they are typically used for things like home automation, smart HVAC (Heating, ventilation, and air conditioning)control, and smart buildings.
Tree Topology
Also known as Hierarchical Topology, this is the most common form of network topology in use presently.This topology imitates as extended Star topology and inherits properties of bus topology.
This topology divides the network in to multiple levels/layers of network. Mainly in LANs, a network is bifurcated into three types of network devices. The lowermost is access-layer where computers are attached. The middle layer is known as distribution layer, which works as mediator between upper layer and lower layer. The highest layer is known as core layer, and is central point of the network, i.e. root of the tree from which all nodes fork.
All neighboring hosts have point-to-point connection between them.Similar to the Bus topology, if the root goes down, then the entire network suffers even.though it is not the single point of failure. Every connection serves as point of failure, failing of which divides the network into unreachable segment.
Tree topology is used to identify the system on the network, to share information across network and allows users to have many servers on the network. Tree topology is the best topology because the signals that are transmitted by the root nodes are received by all the computers at the same time.
Daisy Chain
This topology connects all the hosts in a linear fashion. Similar to Ring topology, all hosts are connected to two hosts only, except the end hosts.Means, if the end hosts in daisy chain are connected then it represents Ring topology.
Each link in daisy chain topology represents single point of failure. Every link failure splits the network into two segments.Every intermediate host works as relay for its immediate hosts.
Hybrid Topology
A network structure whose design contains more than one topology is said to be hybrid topology. Hybrid topology inherits merits and demerits of all the incorporating topologies.
The above picture represents an arbitrarily hybrid topology. The combining topologies may contain attributes of Star, Ring, Bus, and Daisy-chain topologies. Most WANs are connected by means of Dual-Ring topology and networks connected to them are mostly Star topology networks. Internet is the best example of largest Hybrid topology
A hybrid topology is a combination of two or more topologies. For example, if you combine Ring and star topology to make bigger network then it will be called hybrid network or hybrid topology. ... Most common hybrid topologies include star-bus and star-ring network.29-Jul-2020
These topologies can include a mix of bus topology, mesh topology, ring topology, star topology, and tree topology. The choice to use a hybrid topology over a standard topology depends on the needs of a business, school, or the users.03-Jun-2020
Network Topologies Explained with Examples
This tutorial explains network topologies (Bus, Star, Ring, Mesh, Point-to-point, Point-to-multipoint, and Hybrid) in detail with their advantages and disadvantages.
Network topology is the layout of a network. It consists of two parts; physical and logical. The physical part describes the physical layout of a network while the logical part describes how the data flows in that network. Both, physical and logical parts are also known as the physical topology and the logical topology.
Physical part (topology) + Logical part (topology) = Network topology
Types of network topology
The popular types of network topology are; Bus, Star, Hybrid, Ring, Mesh, point-to-point, and point-to-multipoint. Let’s understand each of these types in detail.
Bus topology
In this topology, all computers connect through a single continuous coaxial cable. This cable is known as the backbone cable. Both ends of the backbone cable are terminated through the terminators. To connect a computer to the backbone cable, a drop cable is used. To connect the drop cable to the computer and backbone cable, the BNC plug and BNC T connector are used respectively.
The following image shows the bus topology.
When a computer transmits data in this topology, all computers see that data over the wire, but only that computer accepts the data to which it is addressed. It is just like an announcement that is heard by all but answered only by the person to whom the announcement is made.
For example, if in the above network, PC-A sends data to the PC-C then all computers of the network receive this data but only the PC-C accepts it. The following image shows this process.
If PC-C replies, only the PC-A accepts the return data. The following image shows this process.
The following table lists the advantages and disadvantages of the bus topology.
This topology is no longer used. But there was a time when this topology used to be the first choice among the network administrators. The concept that this topology uses to transmit the data is also used in the other topologies.
Star topology
In this topology, all computers connect to a centralized networking device. Usually, a networking switch or a Hub (in earlier days) is used as the centralized device. Each computer in the network uses its own separate twisted pair cable to connect to the switch. Twisted pair cable uses RJ-45 connectors on both ends.
The following image shows an example of the star topology.
To transmit data, the star topology uses the same concept which the bus topology uses. It means, if you build a network using the star topology, then that network will use the bus topology to transmit the data.
The following table lists the advantages and disadvantages of the star topology.
In modern computer networks, the star topology is the king. Nearly all new network installations, including small home and office networks, use some form of the star topology.
Hybrid Topology
This topology is a mix of two or more topologies. For example, there are two networks; one is built from the star topology and another is built from the bus topology. If we connect both networks to build a single large network, the topology of the new network will be known as the hybrid topology.
You are not restricted to the bus and star topologies. You can combine any topology with another topology. In modern network implementations, the hybrid topology is mostly used to mix the wired network with the wireless network.
The following image shows an example of the hybrid network topology.
Unlike a wired network, a wireless network does not use cables to connect computers. A wireless network uses radio spectrum to transmit data.
Ring topology
In this topology, all computers connect in a circle. Each computer directly connects to two other computers in the network. Data moves down a one-way path from one computer to another. When data signals pass from one computer to the next, each computer regenerates the signals. Since the signals are regenerated on each passing computer, the quality of the signals remains constant throughout the ring.
The following image shows a typical ring topology.
The following table lists the advantages and disadvantages of the ring topology.
Like the bus topology, this topology is also no longer used in modern networks. This topology was originally developed by IBM to overcome the existing drawbacks of the bus topology.
Mesh Topology
In this topology, multiple paths exist between end devices. Based on paths, a mesh topology can be divided into two types; fully meshed and partially meshed. If a direct path exists from each end device to every other end devices in the network, it’s a fully meshed topology. If multiple paths exist between the end devices in the network, it’s a partially meshed topology.
To know how many connections require to make a network fully meshed, we can use the following formula.
Required connections = n * (n-1)/2
Here, n is the number of end devices or locations.
For example, to make a fully meshed network of 4 end devices, we need 4*(4-1)/2 = 6 connections.
We can also use this formula to figure out whether a network is fully meshed or partially meshed. If the number of connections in a network is less than the total required number of the connections then the network is considered as the partially meshed network. For example, a network of 4 end devices has less than 6 connections, then it will be considered as the partially meshed network.
The following image shows an example of both types.
Mesh topology is commonly used in the WAN network for backup purposes. This topology is not used in the LAN network implementations.
Point-to-multipoint topology
In this topology, an end device connects directly to multiple end devices in the network. Just like mesh topology, this topology is also used in the WAN network to connect multiple remote sites/locations/offices with a central site/location/office.
The following image shows an example of the point-to-multipoint topology.
Partially meshed topology and the point-to-multipoint topology are the same except the number of connections. In partially meshed topology number of connections are higher the point-to-multipoint topology.
Point-to-point topology
This is the simplest form of network topology. In this topology, two end devices directly connect with each other. The following image shows a few examples of this topology.
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