Installation manual

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spanning-tree mode
This command selects the spanning tree mode for this switch. Use the no form to restore
the default.
Syntax
spanning-tree mode {stp | rstp
| mstp}
no spanning-tree mode
• stp - Spanning Tree Protocol (IEEE 802.1D)
• rstp - Rapid Spanning Tree Protocol (IEEE 802.1w)
• mstp - Multiple Spanning Tree (IEEE 802.1s)
Default Setting
rstp
Command Mode
Global Configuration
Command Usage
• Spanning Tree 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 between 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 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.
• Multiple Spanning Tree Protocol
- To allow multiple spanning trees to operate over the network, you must configure
a related set of bridges with the same MSTP configuration, allowing them to
participate in a specific set of spanning tree instances.
- A spanning tree instance can exist only on bridges that have compatible VLAN
instance assignments.