Layer 2 loop detection is a security mechanism used to detect loops on a Layer 2 network. When a Layer 2 loop occurs, a large number of packets will be repeatedly sent to a router's CPU. The traffic burst overloads the CPU, causing normal protocol packets to fail to be sent to the CPU. As a result, normal services will be interrupted. Layer 2 loop detection determines whether a loop has occurred based on information about packets sent to the CPU. After detecting a loop, a router will take the configured responsive action. For example, the system may send a trap to the network management system (NMS) or shut down the interface where the loop has occurred.
If Layer 2 loop detection is enabled, the system can rapidly locate the interface where a loop has occurred and send a trap or shut down the interface. This function minimizes service loss caused by Layer 2 loops.
Layer 2 loop detection offers the following benefits: