Cisco Enhancements to STP

The following sections cover items that Cisco has developed to enhance the performance of STP, thus decreasing your convergence times. These features include Cisco's proprietary PortFast, UplinkFast, and BackboneFast.

PortFast

Cisco's proprietary PortFast feature reduces the size of the STP database by excluding ports that do not have bridges or switches connected to them and removing them from the STP topology, thereby minimizing downtime when changes occur in a switched network. When a change occurs, STP flushes the content-addressable memory (CAM) table, thereby preventing any communication between devices until STP has the ports go through the blocking, listening, learning, and forwarding states. Using the PortFast ...

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