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•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 Tre e Protocol
Uses RSTP for the internal state machine, but sends only 802.1D BPDUs.
- This creates one spanning tree instance for the entire network. If multiple
VLANs are implemented on a network, the path b etween specific VLAN
members may be inadvertently disabled to prevent network loops, thus
isolating group members. When operating multiple VLANs, we
recommend selecting the MSTP option.
• Rapid Span ning 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.
Example
The following example configures the switch to use Rapid Spanning Tree:
Console(config)#spanning-tree mode rstp
Console(config)#