D-Link DES-3326 User Manual page 373

DES-3326 Layer 3 Fast Ethernet Switch User's Guide
U
NDERSTANDING AND
T
ROUBLESHOOTING THE
S
When the spanning-tree algorithm determines a port should be
transitioned to the forwarding state, the following occurs:
The port is put into the listening state where it receives
BPDUs and passes them to the switch's CPU.
packets from the CPU are processed. If no BPDUs that
suggest the port should go to the blocking state are
received:
The port waits for the expiration of the forward delay
timer. It then moves to the learning state.
In the learning state, the port learns station location
information from the source address of packets and adds
this information to its forwarding database.
The expiration of forwarding delay timer moves the port to
the forwarding state, where both learning and forwarding
are enabled. At this point, packets are forwarded by the
port.
Understanding and Troubleshooting the Spanning Tree Protocol
PANNING
P
ROTOCOL
E
T
REE
BPDU
359