Which statement is true about the port roles of the 802.1w Rapid Spanning Tree Protocol?
- Cisco-proprietary enhancements to the legacy 802.1D, such as UplinkFast and BackboneFast, are compatible with RSTP.
- An alternate or backup port can immediately change to a forwarding state without waiting for the network to converge.
- It takes an edge port 15 seconds to go from blocking to forwarding.
- Ports are manually configured to be in the designated role.
Explanation: In order to create a loop-free topology, 802.1w RSTP has the following port roles: root, designated, alternate, edge, and backup. RSTP is able to actively confirm that a port can safely transition to the forwarding state without having to rely on a timer configuration.