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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 11 Configuring STP
Configur ing Spanning-Tree F eatures
Configuring the Hello Time, page 11-19
Configuring the Forwarding-Delay Time for a VLAN, page 11-19
Configuring t he M axi mu m-Ag ing Time for a V LA N, p age 11- 20
Configuring STP for Use in a Cascaded Stack, page 11-20

Default STP Configuration

Table 11-3 shows the default STP configuration.

STP Configuration Guidelines

If more VLANs are defined in the VTP than there are spanning-tree instances, you can enable STP 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 12,
Configuring RST P and MSTP.
If 64 instances of spanning tree are already in use, you can disable STP on one of the VLANs and then
enab le it on the VL AN wher e you want it t o run. Use the no spanning-t ree vlan vlan-id global
configurati on comma nd to disable STP on a specific VLAN, and use the spanning-tree vlan vlan-id
global con figuration co mman d to enable STP on the desired V LAN.
Table 11-3 Default STP Configuration
Feature Default Setting
Enable state Enabled on VLAN 1.
Up to 64 spanning-tree instances can be
enabled.
Switch priority 32768.
Span ning- tree por t pr iori ty (con figurabl e on a per-inte rface b asisused on
interfaces configured as Layer 2 access ports) 128.
Spanni ng-tre e port cost (configur able on a per-inte rface basisuse d on
interfaces configured as Layer 2 access ports) 1000 M bps: 4.
100 Mb ps: 19.
10 Mbps: 100.
Spanning-tree VLAN port priority (configurable on a per-VLAN basisused on
interfa ces c on figured as L ayer 2 t run k po rts) 128.
Spanni ng- tree VLA N p ort co st (c on figurable on a p er-VLAN basi sused on
interfa ces c on figured as L ayer 2 t run k po rts) 1000 M bps: 4.
100 Mb ps: 19.
10 Mbps: 100.
Hello time 2 seconds.
Forward-de lay time 15 second s.
Maximu m- ag ing t im e 20 second s.