Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 473)

Spanning Tree Introduction: STP, RSTP, and MSTP
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 18.5
Spanning Tree Protocol (STP)
STP uses the process described in Table 18-1 to avoid loops.
STP port states In STP mode, each switch port can be in one of five spanning tree states, and one of two
switch states. The state of a switch port is taken into account by STP. The STP port states
(
Table 18-2 ) affect the behavior of ports whose switch state is enabled.
Table 18-2: STP port states
State Meaning
DISABLED STP operations are disabled on the port. The port does not
participate in the operation of the Spanning Tree Algorithm and
Protocol. The port can still switch if its switch state is enabled.
BLOCKING The forwarding process discards received frames and does not
submit forwarded frames for transmission. This is the “standby”
mode.The port does not participate in frame relay.
LISTENING The port is enabled for receiving frames only. The port is preparing to
participate in frame relay. The forwarding process discards received
frames and does not submit forwarded frames for transmission.
LEARNING The port is enabled for receiving frames only, and the Learning
Process can add new source address information to the Forwarding
Database.
FORWARDING The normal state for a switch port. The forwarding process and the
Spanning Tree entity are enabled for transmit and receive operations
on the port.