As mentioned in Chapter 10, Routing and Bridging, there can only be a single path between two network devices. If there is more than one path, then the looping can generate a broadcast storm that brings your network to its knees. It is especially a concern if you have bridged one or more interfaces on your network. One way to prevent looping is to manually configure network ports to ensure there is only one path to each device. The more likely scenario, however, is that you utilize a protocol such as Spanning Tree Protocol (STP), or its successor, Rapid Spanning Tree Protocol (RSTP).

Another situation where looping can occur is when the information in the routing table is incorrect, either through a manual misconfiguration or a failure in automatic route detection. Such errors are often easy to detect, because as with physical loops, they will quickly bog down a network.