Changing The Stp Parameters For A Vlan; Changing The Stp Implementation; Changing The Switch Priority - Cisco WS-C2955T-12 Software Manual

Configuring STP

Changing the STP Parameters for a VLAN

The root switch for each VLAN is the switch with the highest priority and sends topology frames to other
switches in the spanning tree. You can change the root parameters for the VLANs on a selected switch.
These options define how your switch responds when STP reconfigures itself.
Protocol Implementation of STP to use: IBM or IEEE. The default is IEEE.
Priority Value (0 to 65535) used to identify the root switch. The switch with the lowest value has the highest priority
and is selected as the root.
Max age Number of seconds (6 to 200) a switch waits without receiving STP configuration messages before attempting
a reconfiguration. This parameter takes effect when a switch is operating as the root switch. Switches not
acting as the root use the root-switch Max age parameter.
Hello Time Number of seconds (1 to 10) between the transmission of hello messages, which mean that the switch is active.
Switches not acting as a root switch use the root-switch Hello-time value.
Forward Number of seconds (4 to 200) a port waits before changing from its STP learning and listening states to the
Delay forwarding state. This wait is necessary so that other switches on the network ensure that no loop is formed
before they allow the port to forward packets.

Changing the STP Implementation

Beginning in privileged EXEC mode, follow these steps to change the STP implementation. The stp-list
is the list of VLANs to which the STP command applies.
Command
Step 1 configure terminal
Step 2 spanning-tree [vlan stp-list]
protocol {ieee | ibm}
Step 3
end
Step 4
show spanning-tree

Changing the Switch Priority

Beginning in privileged EXEC mode, follow these steps to change the switch priority and affect which
switch is the root switch. The stp-list is the list of VLANs to which the STP command applies.
Command
Step 1
configure terminal
Step 2 spanning-tree [vlan stp-list] priority
bridge-priority
Step 3
end
Step 4
show spanning-tree
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
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Purpose
Enter global configuration mode.
Specify the STP implementation to be used for a spanning-tree instance.
Return to privileged EXEC mode.
Verify your entry.
Purpose
Enter global configuration mode.
Configure the switch priority for the specified spanning-tree instance.
Enter a number from 0 to 65535; the lower the number, the more likely the
switch will be chosen as the root switch.
Return to privileged EXEC mode.
Verify your entry.
Chapter 6 Configuring the System
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