CertiGuide to A+ (A+ 4 Real)  9  Chapter 13: Basic Networking Terminology       9  OSI Reference Model and Networking Protocols and Technologies            9  Layer 2 - Data Link Layer                 9  Network Topology

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Ring is the topology that is equivalent to the bus, but the ends are connected with each other. The inadequacies of the bus are inherent in this topology. With failure of the first host, the work of all network is interrupted, therefore, it is necessary to accept special measures of prevention, and for creating a double ring, a redundant ring, etc., that connects the same devices. In order to provide reliability and flexibility each networking device is part of two independent ring topologies. From the logical point of view, the data is transferred on a ring from one computer to another and, as a rule, in one direction. In a double ring the data is transferred to the first ring and if it is down, is transferred at once to another. However, this topology is very convenient for a feedback organization; data makes a circle then comes back to the source that can check the process of delivery of the data to the addressee. This property is often used for testing connections and seeking out an incorrectly working unit. Often these days, the ring is incorporated in a central MAU ¹⁸¹ or MSAU, which is like a hub. All the hosts connect to the MAU, so if one host connection fails, the rest of the Ring will still function. If the MAU fails however, the entire Ring will fail.

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