Default Spanning-Tree Configuration; Spanning-Tree Configuration Guidelines - Cisco Catalyst 3120 Software Manual

Chapter 17 Configuring STP
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Default Spanning-Tree Configuration

Table 17-3
Table 17-3 Default Spanning-Tree Configuration
Feature
Enable state
Spanning-tree mode
Switch priority
Spanning-tree port priority (configurable on a per-interface basis)
Spanning-tree port cost (configurable on a per-interface basis)
Spanning-tree VLAN port priority (configurable on a per-VLAN basis)
Spanning-tree VLAN port cost (configurable on a per-VLAN basis)
Spanning-tree timers

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
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.
OL-12247-01
Configuring the Switch Priority of a VLAN, page 17-21
Configuring Spanning-Tree Timers, page 17-22
shows the default spanning-tree configuration.
(optional)
Default Setting
Enabled on VLAN 1.
For more information, see the
Spanning-Tree Instances" section on
page
PVST+. (Rapid PVST+ and MSTP are
disabled.)
32768.
128.
1000 Mb/s: 4.
100 Mb/s: 19.
10 Mb/s: 100.
128.
1000 Mb/s: 4.
100 Mb/s: 19.
10 Mb/s: 100.
Hello time: 2 seconds.
Forward-delay time: 15 seconds.
Maximum-aging time: 20 seconds.
Transmit hold count: 6 BPDUs
Chapter 18, "Configuring MSTP."
Cisco Catalyst Blade Switch 3120 for HP Software Configuration Guide
Configuring Spanning-Tree Features
(optional)
17-10.
"Supported
17-13