Network Topologies. Bus Topology
All computers on the network are connected by lines of communication. Geometric arrangement of lines relative to hosts and physical connection to the network nodes called the physical topology. Depending on the topology of the network are distinguished: the bus, ring, star, hierarchical and arbitrary structure. distinguish between physical and logical topology. The logical and physical topology of the network independent of one another. The physical topology – a geometry of networking, and the logical topology determines the direction of flow of data between network nodes and transmission technology. Currently, local networks, the following physical topology:
- physical “bus” (bus);
- physical “star” (star);
- physical “ring” (ring);
- physical “star” and a logical “ring” (Token Ring).
Network with bus topology using mono line (coaxial cable) data, which are installed at the ends terminating resistors (terminators). Every computer connected to the coaxial cable with T-connector (T – connector). The data from the transmitting node are transmitted via both ways, reflecting from the terminal terminators. Terminators prevent signal reflections, ie used to extinguish the signals that reach the ends of the data link. Thus, the information is shared by all nodes, but only accepted by the node to which it is intended. In topology, logical bus communication media are used together at the same time all the PCs on your network, and the signals from the PC are released simultaneously in all directions through the medium of transmission. Since the transmission of signals in the physical topology of the bus is a broadcast, ie signals propagate simultaneously in all directions, then the logical topology of the network is a logical bus.
This topology is used in local area networks with the architecture of Ethernet (10Base-classes 5 and 10Base-2 for the thick and thin coaxial cable, respectively).
Advantages of bus topology networks:
- the failure of one node does not affect the operation of the network as a whole;
- network easily set up and configure;
- network resistant to faults of individual nodes. Disadvantages network bus topology:
- Cable break can affect the entire network;
- Limited cable length and number of stations;
- difficult to determine the defect in the