Disabling Stp; Configuring The Root Switch - Cisco Catalyst 2950 Software Manual

Chapter 9 Configuring STP
Table 9-2 Default STP Configuration (continued)
Feature
Forward-delay time
Maximum-aging time
Port Fast
BPDU guard
UplinkFast
BackboneFast
Root guard

Disabling STP

STP is enabled by default on VLAN 1 and on all newly created VLANs up to the spanning-tree limit
specified in
When STP is disabled and loops are present in the topology, excessive traffic and indefinite packet
Caution
duplication can drastically reduce network performance.
Beginning in privileged EXEC mode, follow these steps to disable STP on a per-VLAN basis:
Command
Step 1
configure terminal
Step 2
no spanning-tree vlan vlan-id
Step 3 end
Step 4
show spanning-tree vlan vlan-id
Step 5
copy running-config startup-config
To re-enable STP, use the spanning-tree vlan vlan-id global configuration command.

Configuring the Root Switch

The switch maintains a separate spanning-tree instance for each active VLAN configured on it. A bridge
ID, consisting of the switch priority and the switch MAC address, is associated with each instance. For
each VLAN, the switch with the lowest bridge ID becomes the root switch for that VLAN.
78-11380-03
Table 9-2. Disable STP only if you are sure there are no loops in the network topology.
Purpose
Enter global configuration mode.
Disable STP on a per-VLAN basis.
For vlan-id, the range is 1 to 1005. Do not enter leading zeroes.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Default Setting
15 seconds.
20 seconds.
Disabled on all interfaces.
Disabled on the switch.
Disabled on the switch.
Disabled on the switch.
Disabled on all interfaces.
Catalyst 2950 Desktop Switch Software Configuration Guide
Configuring Basic STP Features
9-21