Listening State
The listening state is the first transition for a port from the blocking state. Listening is an opportunity for the switch to receive BPDUs that may tell the switch that the port should not continue to transition to the forwarding state, but should return to the blocking state (that is, a different port is a better choice).
There is no address learning or packet forwarding from a port in the listening state.
A port in the listening state does the following:
•Discards frames received from the network segment to which it is attached.
•Discards packets sent from another port on the switch for forwarding.
•Does not add addresses to its forwarding database
•Receives BPDUs and directs them to the CPU.
•Processes BPDUs received from the CPU.
•Receives and responds to network management messages.
