Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) - Manual (Page 390)

334 Brocade 6910 Ethernet Access Switch Configuration Guide
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Spanning Tree Commands
• 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.
• Be careful when switching between spanning tree modes. Changing modes stops all
spanning-tree instances for the previous mode and restarts the system in the new mode,
temporarily disrupting user traffic.
Example
The following example configures the switch to use Rapid Spanning Tree:
Console(config)#spanning-tree mode rstp
Console(config)#
spanning-tree pathcost method
This command configures the path cost method used for Rapid Spanning Tree and Multiple
Spanning Tree. Use the no form to restore the default.
Syntax
spanning-tree pathcost method {long | short}
no spanning-tree pathcost method
long - Specifies 32-bit based values that range from 1-200,000,000. This method is based
on the IEEE 802.1w Rapid Spanning Tree Protocol.
short - Specifies 16-bit based values that range from 1-65535.
This method is based on the IEEE 802.1 Spanning Tree Protocol.
Default Setting
Long method
Command Mode
Global Configuration