SPANNING TREE COMMANDS
spanning-tree mode
Use this command to select the Spanning Tree mode for this switch. Use the no form to disable it.
Syntax
spanning-tree mode {stp rstp} no spanning-tree mode
•stp - Spanning Tree Protocol (IEEE 802.1D)
•rstp - Rapid Spanning Tree Protocol (IEEE 802.1w)
Default Setting
rstp
Command Mode
Global Configuration
Command Usage
•Spanning Tree Protocol
STP creates one Spanning Tree instance for the entire network. If multiple VLANs are implemented on a network, the path between specific VLAN members may be inadvertently disabled to prevent network loops, thus isolating group members. STP uses RSTP for the internal state machine, but sends only 802.1D BPDUs.
•Rapid Spanning Tree Protocol
RSTP supports connections to either STP or RSTP nodes by monitoring the incoming protocol messages and dynamically adjusting the type of protocol messages the RSTP node transmits, as described below:
-STP Mode – If the switch receives an 802.1D BPDU after a port’s migration delay timer expires, the switch assumes it is connected to an 802.1D bridge and starts using only 802.1D BPDUs.
-RSTP Mode – If RSTP is using 802.1D BPDUs on a port and receives an RSTP BPDU after the migration delay expires, RSTP restarts the migration delay timer and begins using RSTP BPDUs on that port.
