Network users complain that the network is running very slowly. Upon investigation, a network technician discovers 100% link utilization on all the network devices. Also, numerous syslog messages are being generated that note continuous MAC address relearning. What is the most likely cause of the problem?
- The routing protocol has been misconfigured and a routing loop is evident.
- A Layer 2 STP looping condition is present.
- The dynamic routing protocol has not yet converged the network.
- An incorrect encapsulation has been configured on one of the trunks that connect a Layer 2 device to a Layer 3 device within the affected segment.
- Keepalives are expected but do not arrive.
Explanation: High CPU consumption and low free memory space are common symptoms of a Layer 2 forwarding loop. In Layer 2 forwarding loops, besides constantly consuming switch bandwidth, the CPU spikes as well. As the packet is received on a different interface, the switch must move the MAC address from one interface to the next. The network throughput is impacted drastically, users will probably notice a slow-down on their network applications, and the switches might crash because of an exhausted CPU and low memory resources.