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Cisco Systems IntelligentGigabit Ethernet Switch Modules for the IBMBladeCenter, Software Configuration Guide
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Chapter9 Configuring STP
Configuring Spanning-Tree Features
Default Spanning-Tree ConfigurationTable 9 -3 shows the default spanning-tree configuration.
Spanning-Tree Configuration GuidelinesIf more VLANs are defined in the VTP than there are spanning-tree instances, you can enable PVST+
or rapid PVST+ on only 64 VLANs. If the number of VLANs exceeds 64, we recommend that you enable
the MSTP to map multiple VLANs to a single spanning-tree instance. For more information, see the
Chapter 10, “Configuring MSTP.”
If 64 instances of spanning tree are already in use, you can disable spanni ng tree on one of the VLANs
and then enable it on the VLAN where you want it to run. Use the no spanning-tree vlan vlan-id global
configuration command to disable spanning tree on a speci fic VLAN, and use the spanning-tree vlan
vlan-id global configuration command to enable spanning tree on the desired VLAN .
Table9-3 Default Spanning-Tree Configuration
Feature Default Setting
Enable state Enabled on VLAN 1 (default management
VLAN for the management module).
Enabled on VLAN 2 (default operational
traffic VLAN for the external ports and the
internal Gigabit Ethernet ports).
For more information, see the “Supported
Spanning-Tree Instances” section on
page9-9.
Spanning-tree mode Rapid PVST+. (PVST+ and MSTP are
disabled.)
Switch priority 32768.
Spanning-tree port priority (configurable on a per-interface basis) 128.
Spanning-tree port cost (configurable on a per-interface basis) 1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
Spanning-tree VLAN port priority (configurable on a per-VLAN basis) 128.
Spanning-tree VLAN port cost (configurable on a per-VLAN basis) 1000 Mbps: 4.
100 Mbps: 19.
10 Mbps: 100.
Spanning-tree timers Hello time: 2 seconds.
Forward-delay time: 15 seconds.
Maximum-aging time: 20 seconds.