D-Link DES-3326S manual Blocking State, Port in the blocking state does the following

DES-3326S Layer 3 Fast Ethernet Switch User’s Guide

Blocking State

A port in the blocking state does not forward packets. When the switch is booted, a BPDU is sent to each port in the switch putting these ports into the blocking state. A switch initially assumes it is the root, and then begins the exchange of BPDUs with other switches. This will determine which switch in the network is the best choice for the root switch. If there is only one switch on the network, no BPDU exchange occurs, the forward delay timer expires, and the ports move to the listening state. All STP enabled ports enter the blocking state following switch boot.

A port in the blocking state does the following:

•Discards packets 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.

•Does not transmit BPDUs received from the CPU.

•Receives and responds to network management messages.

320Understanding and Troubleshooting the Spanning Tree Protocol