TOI Author :: Kailin Zhang

The new feature maintains STP restartability while a portfast-enabled port’s link status changes. In older releases, when portfast is enabled on an interface and the interface is flapping, i.e., going up and down, STP becomes non-restartable. After the new feature is introduced, STP remains restartable during port flapping. This may be applicable in several scenarios, but the most common usage is to keep STP restartable after endpoints are connected and disconnected. This feature is important for SSU because an SSU can only be performed while STP is restartable. After the portfast port's link status changes, SSU can still be conducted.

In STP Rapid-PVST mode, when multiple VLANs are assigned to different interfaces using switchport mode access and these interfaces are interconnected, the VLANs perceive each other as part of the same VLAN, thereby forming a large single VLAN network.