Network topology

LAN topology like star

The concept of this topology of a LAN was borrowed from area of big computers when all data obtained from peripheral devices are processed by the head machine. At the same time data exchange between peripheral jobs happens via the head machine which is central node of a LAN. Such topology of a local computer network is used, for example, by e-mail RELCOM.

Capacity of such local computing is guaranteed for each workstation of network and depends only on the computing power of a node. Emergence of collisions in network of such topology is impossible.

The networks built on topology "star" have the greatest possible high-speed performance as data between workstations are transmitted through central node on separate lines which are used only by these stations. Interrogation rate for information transfer between stations is rather small.

Performance of a LAN is in direct dependence on the power of a file server. If the central node fails, the network also stops work.

Installation of cable connection is simple as each workstation is connected only with the head machine, but the total cost of a cable can turn out rather big, and increases in case of arrangement of the main machine not in the center of network.

Installation of a separate cable from the new workstation to the head machine is necessary for expansion of network.

Network management is exercised from its center, in the center the data protection mechanism is implemented.

Ring topology of a LAN

Ring topology of a local computer network means that workstations are connected with each other around: the first with the second, third with the fourth and so on. The last station contacts the first, closing a ring.

The complexity and cost of installation of cables between workstations directly depends on geographic location of stations from each other.

Information transfer is performed around. The operating station receives a request from a ring, and then sends information on the specific address. The information transmission system such LAN is considered rather effective as messages can be sent one after another quickly enough, besides it is easy to send a request for all workstations of a ring. Transmission time of information grows with increase in number of stations in a LAN.

Lack of local networks with a ring topology that at failure at least of one workstation all network becomes disabled. It is simple to detect any fault of cable connection in such network.

Connection of the new station in a local network requires temporary shutdown of network. Extent of such network can be unlimited.

Logical ring local computer network

The logical ring local computer network is a special form of topology of a LAN. It represents connection of several networks organized on topology a star. For connection in network of separate "stars" special hubs which are often called hubs are used. Hubs can be active or passive. Difference of active hubs – available the alternate amplifier which serves for connection of 4 - 16 workstations. The passive hub is expected three workstations and in essence is just razvetvitelny device. Control of each specific station in network is exercised in the same way as in a ring LAN. Each operating station of network receives own address to which transfer of management is performed. Failure in work as one of machines can influence only the subordinate stations, failure of all network is improbable.

Bus topology of a LAN

The bus topology of network assumes that Wednesday for data transmission the communication way to which all workstations are connected serves. Each of stations of network can come into direct contact with the LAN any other station.

Connection or shutdown of workstations is performed without interruption of work of a LAN, the status of separate workstations in general does not affect operability of network.