The topology of the local network is a logical schemeconnection of computers or network nodes by communication channels. Topology refers to the geometric representation of relationships in a network. There are a lot of different topologies. The main ones are "bus", "star", "ring", in addition, there are additional ones - "tree", "graph", "lattice" and others.
The topology of "star" networks is suchA kind of network when all computers are connected through a central node. The role of the central node is usually played by a server or a hub. This topology has its advantages and disadvantages. The advantages include high performance, since the performance of the entire network depends directly on the maximum performance of the central device. The advantage is that there is no possibility of collision of data that is transmitted over the network, because the data exchange between the station and the server is carried out on a separate channel and does not affect other computers.
The central node is the most vulnerable placetopology, the reliability of the network is determined precisely by the reliability of the central element. If for some reason the central node stops working, the network will cease to function. The downside of the "star" is also called the high cost of connection, because every new subscriber of the network needs to maintain a separate line.
The topology of the "ring" networks is based on the fact that allWorkstations are connected to a line closed in a ring, from where the name appeared. The signals in the "ring" are transmitted only in one direction and go through all the computers sequentially. The essence of the transfer of information is that a special marker is transferred from the computer to the computer until it is received by the workstation to which the data should be transmitted. The computer, having received the token, creates a packet containing the destination address and data, and then sends the packet along the ring. The information passes through each station until it reaches the one whose address is identical to the recipient's address. After this, the receiving party sends a confirmation to the source of the data receipt. The advantages of this topology is that the sending of messages is quite effective, because you can send several messages one by one. The length of such a network can reach considerable sizes without the use of any signal amplifiers. A huge disadvantage is the low reliability of the network with such a topology, because the failure of any one computer will lead to the collapse of the entire system. To connect a new client, you will have to disconnect the entire network, and if the number of subscribers is large, the speed of work is significantly slowed down. The total network performance is determined by the performance of the slowest computer.
The topology of the "bus" networks is that allsubscribers are connected to one common information transfer channel. In this case, customers can come into contact with any computer on the network. Data is sent to all computers, but only the station whose address corresponds to the recipient's address can receive information. Such a network topology has several important advantages. First, all the data is on the network and accessible to each workstation; secondly, computers can be connected independently; thirdly, such networks are cheaper due to the fact that you do not need to spend money on laying additional lines by connecting a new subscriber. Has such a network of high reliability. Unfortunately, the transmission speed is quite low, since all data is circulated on one bus, and the speed depends on the number of connected clients. The more this number, the slower the information is transmitted. Security in such a network is at a low level, because the data on each workstation can be accessed from another computer.
The considered topologies of local networks are quite effective, but in practice the simultaneous combination of several topologies is often used.
