Arriving at various companies, you can pay attention to the fact that the network is arranged there in different ways - somewhere a “star” is used, somewhere a “ring”, and somewhere a “bus”. The network topology strongly influences the quality and speed of data exchange between computers, but at the same time, many often do not know the main advantages and disadvantages of each individual option.
What it is?
Despite the fact that this option is the most common today, the term "topology" does not provide only for the "bus" technology. A network topology is simply the union of several computers on a network, so it can be called a similar version of concepts such as configuration or network structure. In addition, the concept of “topology” also contains a large number of rules that determine the location of computers, the technology of cable laying and placement of binding equipment, as well as many other things.
What can she be?
To date, three main variants of such a combination of computers have formed - this is the "star", "ring" and "bus". The topology in each case is different from the rest, and also has its own characteristics and advantages. That is why it is important to know these subtleties before conducting a network between computers at a particular object.
"Tire"
According to the "bus" technology, the topology provides for the use of a single cable, with which all workstations used are interconnected.
Thus, a single cable is used by each station in turn, and all messages sent by these stations can be received and listened to by any computer on the network. From this stream, all workstations select only those messages that were originally addressed to them.
What are the benefits?
The advantages of the bus topology are as follows:
- The setup is extremely simple for any advanced user.
- The system is quite simple to install and at the same time causes a minimum of financial costs if all workstations are located at a short distance between each other.
- If a particular station in the network breaks down or starts to fail, all the others continue to work in the previous mode without any problems.
What are the disadvantages?
There are also disadvantages to the bus topology:
- If a malfunction occurs in any place, the entire network instantly fails.
- It is difficult enough to find any problems if they arise.
- Quite low performance compared to other technologies. This is due to the fact that the bus network topology provides for the simultaneous transfer of data from only one computer, and if the number of workstations increases, the performance of the network used decreases in parallel.
- Low scalability. To add new workstations, it is necessary to completely replace the sections of the already used "bus".
It was this technology that was used to connect computers to the local network when using a coaxial cable. In this case, in the role of the “bus”, pieces of coaxial cable were used, combined between the failure using T-connectors. The "bus" is laid completely through the entire room, after which it is connected to each individual computer, and the side terminal of the connector is inserted into the connector installed on the network card.
Due to the fact that such equipment is already hopelessly outdated, and the star network topology has become more widespread, the bus is practically not used, but it can still be found at various enterprises.
"Ring"
The "ring" is such a topology of the local network, in accordance with which various all workstations are connected together in series, forming a completely vicious circle. In such a network, data is transmitted from one workstation to another in a single direction, with each individual computer acting as a repeater, relaying the message to the next, thus forming a kind of relay. Such a system already has little in common with what the common bus topology is, and therefore has a lot of its features and advantages.
What are the benefits?
- Computers are simply networked together.
- There is practically no need to use additional equipment.
- It is possible to achieve stable operation without any noticeable drop in the speed of data broadcasting with a serious network load.
- Any workstation should be actively used in the data transfer procedure, and if at least one computer breaks down, or a cable breaks in a certain place, the whole system will completely cease to function.
- If a new workstation will be connected, the network must be turned off for a certain time, since ring opening is required during the installation of new equipment.
- The system has a rather complicated configuration and settings.
- If any malfunctions occur, it is even difficult for specialists to find what exactly the malfunction is.
What are the disadvantages?
In connection with these minuses, it is not so often possible to meet the use of ring topology, and it is most often found in fiber networks of the Token Ring standard.
"Star"
If each workstation is connected directly to a central device, which can serve as a router or a switch, then this is a star topology. The "tire" has been replaced with this technology over time, as it is characterized by higher productivity and efficiency. This technology provides for the management of all packet movements in the network directly by the central device, and each computer through its own network card is connected to this switch with a completely separate cable.
If necessary, it is possible to combine several networks using the described topology at the same time, as a result of which a network configuration with a tree topology will be obtained. Tree topology is distributed in large organizations, but it differs in a number of its features and implementation subtleties.
Today, the star topology is used as the basis for the construction of almost all local area networks, and, in particular, this is the result of a number of advantages of this technology for combining computers.
What are the benefits?
- If any particular station breaks (or its cable is damaged), this does not affect the operation of the entire network, that is, all other equipment continues to work stably.
- Great scalability. In order to connect a new workstation, you just need to lay a separate cable from the switch.
- You can simply find it, and then fix the malfunctions or any breaks in the network.
- Extremely high performance, especially when compared with similar topology options.
- Ideal ease of setup and administration of all equipment.
- You can easily integrate additional devices into the network.
- If the central switch breaks, the entire network stops working.
- To use network equipment, you also need to allocate additional costs, since it requires the purchase of a separate device to which all computers connected to the network will connect.
- The number of workstations is limited by the number of ports in the central switch used.
What are the disadvantages?
Today, the "star" is the most common technology for modern wired or wireless networks. As an example of a star-shaped topology, one can imagine a network using a twisted-pair cable, as well as a switch, which is a central device. Such networks can often be found today in the predominant majority of companies.
Topology and its significance
The network topology allows you to determine not only the physical location of computers, but, more importantly, provides the nature of the connection between them, as well as various features of the propagation of signals through the network. It is the nature of communication that can determine how fault tolerant the network is, as well as find out the required complexity of the network equipment and the most relevant exchange control method and many other parameters. If the literature considers the topology of local networks “bus” or other technologies, then four completely different concepts can be envisaged that relate to different types of network architecture :
- Physical - the layout of computers, as well as the laying of cables connecting them. In this vein, the passive “star” has no differences from the active one, in connection with which the technology is most often called simply “star”.
- Logical - the structure of connections, as well as how signals propagate through the network. This definition of topology can probably be called the most correct.
- Exchange management - the principle, as well as the sequence of transfer of the right to terminate the network connection between certain computers.
- Information - the direction of information flows that are transmitted through the network.
For example, a network having a physical and logical topology of the "bus" format can use relay control technology to transfer network capture rights as a control, as well as provide simultaneous transfer of all data through a specific dedicated computer. And in such content constitute technology "star".