Application Scenarios for STP/RSTP
On a complex network, multiple physical links are often deployed between two devices to implement link redundancy. However, this may lead to loops, which can cause broadcast storms and damage MAC address entries on network devices.
As shown in Figure 9-14, STP is deployed on the devices. The devices exchange information to discover loops on the network and block a port to trim the ring topology into a loop-free tree topology. The tree topology prevents infinite looping of packets on the network and ensures packet processing capabilities of the devices.