Planet IGSW-2840, User Manual

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User’s Manual of IGSW-2840
535
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. -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 forward-time
This command configures the spanning tree bridge forward time globally for this switch. Use the no form to restore the default.
Syntax
spanning-tree forward-time seconds
no spanning-tree forward-time