18-13
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
OL-12247-04
Chapter 18 Configuring STP
Configuring Spanning-Tree Features
•
Configuring the Switch Priority of a VLAN, page 18-21
(optional)
•
Configuring Spanning-Tree Timers, page 18-22
(optional)
Default Spanning-Tree Configuration
shows the default spanning-tree configuration.
Spanning-Tree Configuration Guidelines
Each stack member runs its own spanning tree, and the entire stack appears as a single switch to the rest
of the network.
If more VLANs are defined in the VTP than there are spanning-tree instances, you can enable PVST+
or rapid PVST+ on only 128 VLANs on the switch or each switch stack. The remaining VLANs operate
with spanning tree disabled. However, you can map multiple VLANs to the same spanning-tree instances
by using MSTP. For more information, see
Chapter 19, “Configuring MSTP.”
If 128 instances of spanning tree are already in use, you can disable spanning 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 specific VLAN, and use the
spanning-tree vlan
vlan-id
global configuration command to enable spanning tree on the desired VLAN.
Table 18-3
Default Spanning-Tree Configuration
Feature
Default Setting
Enable state
Enabled on VLAN 1.
For more information, see the
Spanning-Tree Instances” section on
page 18-10
Spanning-tree mode
PVST+. (Rapid 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 Mb/s: 4.
100 Mb/s: 19.
10 Mb/s: 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 Mb/s: 4.
100 Mb/s: 19.
10 Mb/s: 100.
Spanning-tree timers
Hello time: 2 seconds.
Forward-delay time: 15 seconds.
Maximum-aging time: 20 seconds.
Transmit hold count: 6 BPDUs