Network Topologies: 17 flashcards

Each device (node) is connected to exactly two other devices, forming a circular data path. Data travels in one direction (or sometimes two) around the ring from node to node until it reaches the destination.

Data travels in a single direction around the ring. Each node receives the data, checks if it is the intended recipient, and if not, regenerates and forwards it to the next node.

A token is a special data frame that circulates around the ring. A node can only transmit data when it possesses the token, ensuring orderly access and preventing data collisions.

The entire network fails because the ring is broken. Data can no longer pass through the failed node or link, isolating all devices on either side.

A dual ring uses two concentric rings, with data flowing in opposite directions. If one ring fails, the other can be used, or the two rings can wrap together to bypass the failure, maintaining network connectivity.

It handles heavy loads more effectively than bus topology because each node has a dedicated point-to-point connection to its neighbors, and the token-passing mechanism prevents collisions, allowing predictable performance.

Adding a device requires breaking the ring at some point and inserting the new node, which temporarily disrupts the network. The network must be brought down to add the new device.

Identifying the exact location of a fault can be difficult because data must traverse the entire ring. Network administrators may need to check each node and connection to find the problem.

Ring topology can be faster than bus topology because data travels in a dedicated path without collisions (in token-passing rings), and each node regenerates the signal, reducing attenuation. However, the delay increases with the number of nodes.

The delay increases because data must pass through each intermediate node before reaching its destination. Each node introduces a small amount of latency as it processes and forwards the data.

There is no strict maximum, but practical limits are imposed by performance. As the number of nodes increases, the delay increases, and the network becomes slower. The exact limit depends on the technology and cabling used.

In a token-passing ring, data collisions are avoided entirely because only the node holding the token can transmit. This ensures that data packets do not interfere with each other.

Expanding the network is difficult and disruptive. Adding a new node requires breaking the ring, which temporarily halts network operation. Also, the network must be carefully planned to accommodate future growth.

Each node in a ring topology acts as a repeater, regenerating the signal before forwarding it. This prevents signal degradation over long distances, unlike bus topology where signal quality diminishes along the cable.

Fiber Distributed Data Interface (FDDI) networks use a dual ring topology for high-speed and fault-tolerant backbone networks. Token Ring networks (IEEE 802.5) are also a classic example.

A physical ring has devices connected in a circular physical layout. A logical ring, like in Token Ring over a hub, has devices physically connected in a star but data travels logically in a ring, passing from one device to the next in a predetermined order.

Ring topology is often considered more reliable because a failure in one node or cable does not necessarily bring down the entire network if a dual ring or bypass mechanism is used. In a single ring, however, it is less reliable than a star topology.