What are network topologies? Why are they needed? Where are they used and for what purpose? What types and types of them exist? Is it possible to somehow neutralize the negative aspects of network topologies and strengthen the positive? Here is a short list of questions that will be answered in the framework of this article.
general information
Many people know about network devices. Topologies for the majority are a dark forest. So, let's introduce a small model. We have computers that operate within the same
local network. They are connected via communication lines. Depending on how their interaction is built, the following types of network are distinguished:
- Roundabout.
- Starry.
- Tire.
- Hierarchical.
- Arbitrary.
All of the above applies to physical topology. But there are also logical ones. They are independent of one from the second. So, by the first they mean the geometry of building a network. The logical topology deals with the fact that it directs data flows between different nodes of the network and selects the method of data transfer. Each of the types of relationship construction discussed below has its own characteristics, advantages and disadvantages. Now let's look at the main network topologies.
Tire typology
It is used in those cases when a linear mono channel is used for data transfer. Terminators are installed at its ends. Then each computer is connected to a linear mono channel thanks to the T-connector. Data is transmitted on both sides and reflected from terminal terminators. As can be understood from this, the information in this case goes to all available nodes. But here it can be accepted only by that for which it is intended. The data transmission medium in this case is used by all personal computers that are connected to the network. And the signal that comes from one PC is distributed across all devices. This technology has gained popularity by using the Ethernet architecture. What advantages does this network equipment provide
(network topology)? First you need to note the ease in setting up and configuring the network. Also, if one node fails, then it will be able to continue its work as a whole. Thanks to this, we can say that networks built according to the bus typology have significant resistance to malfunctions. But there are also disadvantages. First of all, it is necessary to note the restrictions regarding the cable length, as well as the number of workstations. In addition, the break of the linear mono channel negatively affects the performance of the entire network. Because of this, it is often difficult to locate a defect, especially if it is covered by insulation.
Network Topology Star
In this case, twisted pair cable, each workstation is connected to a hub or hub. Thanks to them, a parallel connection of all personal computers is provided. Through a hub or PC hub and communicate with each other. Sent data arrives at all workstations. But only the one for which they were intended can accept them. Regarding the advantages, it is worth noting that it is easy to connect a new personal computer to the network. It is also resistant to malfunctions of individual nodes and breaks in the connection. And all this is complemented by the possibility of centralized management. True, there are certain disadvantages. So, there is a significant consumption of cable. In addition, the failure of the hub or hub will negatively affect the operation of the entire network.
Using a central hub
This network typology is based on the previous type of network creation. The main role in this case is played by the central hub. It is an intelligent device that provides a
serial connection of different stations according to the "output-input" principle, that is, thanks to it, each computer is connected to two more workstations. For stable operation, there are primary and backup rings. Due to this, it is possible to maintain the network's operability even in the presence of significant damage. The problem point is simply turned off. For data transmission, a special marker is used. It contains the address of the sender and recipient of the information. It should be noted that, in addition to high reliability, this typology also provides equal access to the network to all workstations. But you have to pay for everything. In this case, this refers to high cable consumption and expensive wiring of communication lines.
Tree
This network typology is considered as a combination of several stars. A tree can be in the following states:
- Active.
- Passive.
- True.
Depending on the necessary condition, the responsible staff chooses what to use: central computers or hubs (hubs). Each choice has its advantages and disadvantages. In the first case, we can talk about building a more centralized system with better controllability and the like. But the use of hubs or hubs, as a rule, is much more profitable from a resource and financial point of view.
Ring topology
In this case, the connection
of communication channels into one inextricable circuit is provided. However, it does not have to resemble a circle. In this case, it is envisaged that the output of one personal computer that is connected to the input of another computer will be used for data transfer. Therefore, when the information begins to move from any one particular point, in the end it will be there, having gone through one circle. Data in such rings always moves in one direction. Only the workstation to which it was addressed can recognize and process the received message. When working with the topology, marker access is used. It provides for the right to use the ring in the prescribed manner. During data transfer, a logical ring is used. Creating and configuring this network is very easy. But due to the fact that damage in one place can disable it, in its pure form it is almost not used due to its unreliability. To work in practice, various modifications of this typology can be used.
Combinations
They are used to reduce or eliminate the negative side when creating the relationship between different computers. The most common combined types of network topology are based on stellar, bus and ring technologies. To understand the situation, there are several examples. Take for the first star-bus topology. The main thing in it is the hub. But it can connect not only individual computers, but also entire bus network segments. Of course, not one concentrator can be used, but many. A building architecture with a backbone bus can also be used. The advantage of this combination is that the system administrator can get the advantages of both typologies and can easily influence the number of computers that are connected to the network. Let's look at another example. The star-ring topology will be considered. It combines not computers, but hubs, to which computers are directly connected. Thus, a closed loop is created in which the advantages of both of these topologies are combined, and a number of amenities also appear. An example of such is the fact that all hubs can be assembled in one place. This means that the cable connection points will be located together, and work with them will be greatly simplified.
Conclusion
So we have considered the main types of network topology. The possibilities of building the relationship between different computers presented in the article are the most popular due to their practicality. But in some cases, more specialized network topologies may be needed. Their development or use of already created technologies is carried out taking into account all the features, nuances and aspects necessary for the correct operation. Usually something similar is used only for scientific and military facilities, while for civilian life more than enough the most common approaches are more than enough. After all, the considered network topologies are the achievements of decades!