D-Link DES-3326 User Manual - Blocking State
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
360
Understanding and Troubleshooting the Spanning Tree Protocol
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.