What are network topologies? Why are they needed? Where are they used and for what purpose? What are their types and types? Is it possible to somehow neutralize the negative aspects of network topologies and strengthen the positive ones? Here is a short list of questions that will be answered within the framework of this article.
general information
Many people know about network devices. The topology for the majority is a dark forest. So, let's imagine a small model. We have computers that operate within the same local network. They are connected by means of communication lines. Depending on how their interaction is built, the following types of network are distinguished:
- The ring.
- Starry.
- Shinnuyu.
- Hierarchical.
- Arbitrary.
All of the above applies to physical topology. But there are also logical ones. They are independent one from the second. Thus, the first is the geometry of the network construction. Logical topology deals with the fact that it directs data flows between different nodes of the network and chooses the method of data transmission. Each of the types of interrelationship discussed below has its own peculiarities, advantages and disadvantages. And now let's look at the basic network topologies.
Bus typology
It is used in cases where a mono channel is used for data transmission. Terminators are installed at its ends. Then each computer is connected to a linear mono channel thanks to the T-connector. The data is transmitted on both sides and is reflected from the terminators. As one can understand from this, information in this case comes to all available nodes. But now it can be accepted only by those for whom it is intended. The data transmission medium in this case is used by all personal computers that are connected to the network. A signal that comes from one PC, spreads across all devices. This technology has been popular with the use of Ethernet architecture. What are the advantages of this network equipment (network topology)? For starters, you should note the ease in setting up and configuring the network. Also, if one node fails, it will be able to continue its work as a whole. Due to this, it can be said that the networks constructed according to the bus typology have considerable resistance to faults. But there are disadvantages. First of all, it is necessary to note restrictions on the length of the cable, as well as the number of workstations. In addition, the disruption of the linear mono channel negatively affects the operability of the entire network. Because of this, it is often difficult to determine the location of the defect, especially if it is covered by insulation.
Network topology "Star"
In this case, a twisted pair of each workstation is connected to a hub or hub. Thanks to them, all computers are connected in parallel. Through a hub or a PC concentrator and communicate with each other. The data is sent to all workstations. But they can only be accepted by the one for which they were intended. Concerning advantages, it should be noted that it is easy to connect a new personal computer to the network. Also, it is resistant to malfunctions of individual nodes and disconnections. And it complements all this with the possibility of centralized management. However, there are certain drawbacks. So, there is a significant consumption of the 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 central role in this case is played by the central concentrator. It is an intelligent device that provides a serial connection of different stations on the principle of "output-input", that is, thanks to it, each computer is connected to two more workstations. For stability of functioning, there are basic and spare rings. Due to this, it is possible to maintain the network performance even if there are significant damages. The problem point is simply turned off. A special marker is used for data transmission. 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 for all workstations. But you have to pay for everything. In this case, this refers to a large cable consumption and expensive wiring layout.
Tree
This network typology is considered as a combination of several stars. The tree can be in the following states:
- Active.
- Passive.
- True.
Depending on the condition, the responsible person 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 with a resource-financial plan.
Ring topology
In this case, it is envisaged to connect the communication channels into one unbroken chain. However, it does not need 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 transmission. Therefore, when the information starts to move from one particular point, eventually it will be there in the same way, after going through one circle. The data in such rings always move in one direction. Recognize and process the received message only from the workstation to which it was addressed. When using the topology, the access is token access. It provides for the right to use the ring in the established order. During the data transfer, a logical ring is used. It is quite easy to create and configure this network. But due to the fact that damage in one place can disable it, in its pure form it is almost not used because of its unreliability. To work in practice, various modifications of this typology can be used.
Combinations
They are used to reduce or eliminate the negative sides when creating the relationship between different computers. The most common combined types of network topology are based on the stellar, bus and ring technologies. To understand the situation, you can give a few examples. Take for the first a star-bus topology. The main thing in it is the concentrator. But not only individual computers can be connected to it, but also whole bus network segments. Of course, not one hub 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 take advantage of both typologies and easily affect the number of computers that are connected to the network. Let's look at one more example. The star-ring topology will be considered. It combines not computers, but concentrators, to which computers are directly connected. Thus, a closed loop is created, in which the advantages of these two topologies are combined, and a number of other amenities also appear. An example of this is that all concentrators can be assembled in one place. And this means that the cable connection points will be together, and work with them will be greatly simplified.
Conclusion
Here we also considered the main types of network topology. Presented within the framework of the article, the possibilities of building the relationship between different computers 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 correct operation. Usually something similar is used only for scientific and military facilities, whereas for civil life there are more than enough common approaches. After all, the network topologies considered are decades of work!