Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 476)

Spanning Tree Introduction: STP, RSTP, and MSTP
Software Reference for x310 Series Switches
18.8 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
Rapid Spanning Tree Protocol (RSTP)
RSTP uses the process described in Table 18-1 to avoid loops.
A spanning tree running in STP mode can take up to one minute to rebuild after a topology
or configuration change. The RSTP algorithm provides for a faster recovery of connectivity
following the failure of a bridge, bridge port, or a LAN. RSTP provides rapid recovery by
including port roles in the computation of port states, and by allowing neighboring
bridges to explicitly acknowledge signals on a point-to-point link that indicate that a port
wants to enter the forwarding mode.
In rapid mode, the rapid transition of a port to the forwarding state is possible when the
port is considered to be part of a point-to-point link, or when the port is considered to be
an edge port. An edge port is one that attaches to a LAN that has no other bridges
attached.
Table 18-4: RSTP port states
State Meaning
DISABLED STP operations are disabled on the port.
DISCARDING The port does not 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. The port does not forward any frames.
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.