What Is an Arbitrated Loop?

An arbitrated loop is a type of connection model used in networks in which the network’s devices are in a ring formation. The arbitrated loop used to be less expensive and the preferred connection model, but a decrease in network switch prices changed that. This type of loop is able to support 126 devices and computers at once, and any further devices will be ignored. One problem with using this loop is that all the devices share the overall bandwidth, which means the loop may need a lot of bandwidth to function.

There are many types of loops and network connection models, and the arbitrated loop is characterized by its ring formation. This means all the devices are connected in a ring, and the ring starts and ends with the host computer. For example, if there is a host computer and two devices, then the host would be directly connected to the first device, the first device would be connected to the second and the second device would be connected to the host. Not every device is connected to the host, which decreases the overall amount of cables needed.

For a long time the arbitrated loop was a commonly used and inexpensive network connection model. The competing model, fabric topology, was faster but the required switches initially were very expensive. Technological advances brought down the price of switches, and the arbitrated loop fell out of favor.

The arbitrated loop is able to support a large number of different devices at once, allowing users to make a big network. The number of different devices that officially can be included in the ring is 126, and any extra devices will not properly work with the network. At the same time, if any device goes down, then all the other devices lose their connection to the network, which could be a big problem if any devices regularly malfunction.

Bandwidth usually is precious on a network, because it allows the data to move and is responsible for transfer speeds. A problem with the arbitrated loop is that the overall bandwidth is shared. This means that, if several computers are running intensive applications or downloads, then the other devices will suffer and may function very slowly. Therefore, the loop requires a lot of computer resources, especially if there are a high number of devices on the network at once.