Cisco WS-C2980G-A Software Guide - Page 104

Understanding How STPs Work Chapter 7 Configuring Spanning Tree Figure 7-4 Port 2 in Listening State All segment frames Forwarding Station addresses Port 1 BPDUs Network management and data frames Filtering database System module Frame forwarding Data frames BPDUs Port 2 Network management frames S5693 Listening All segment frames BPDU and network management frames A port in the listening state performs as follows: • Discards frames received from the attached segment • Discards frames switched from another port for forwarding • Does not incorporate station location into its address database (there is no learning at this point, so there is no address database update) • Receives BPDUs and directs them to the system module • Processes BPDUs received from the system module • Receives and responds to network management messages Learning State A port in the learning state prepares to participate in frame forwarding. The port enters the learning state from the listening state. Figure 7-5 shows a port in the learning state. Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide-Release 8.1 7-8 78-15486-01