Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 95
53-1002269-02
Configuring standard STP parameters
6
Enabling or disabling the Spanning Tree Protocol (STP)
STP is enabled by default on devices running Layer 2 code. STP is disabled by default on devices
running Layer 3 code.
You can enable or disable STP on the following levels:
• Globally – Affects all ports and port-based VLANs on the device.
• Port-based VLAN – Affects all ports within the specified port-based VLAN. When you enable or
disable STP within a port-based VLAN, the setting overrides the global setting. Thus, you can
enable STP for the ports within a port-based VLAN even when STP is globally disabled, or
disable the ports within a port-based VLAN when STP is globally enabled.
• Individual port – Affects only the individual port. However, if you change the STP state of the
primary port in a trunk group, the change affects all ports in the trunk group.
NOTE
The CLI converts the STP groups into topology groups when you save the configuration. For
backward compatibility, you can still use the STP group commands. However, the CLI converts the
commands into the topology group syntax. Likewise, the show stp-group command displays STP
topology groups.
Enabling or disabling STP globally
Use the following method to enable or disable STP on a device on which you have not configured
port-based VLANs.
NOTE
When you configure a VLAN, the VLAN inherits the global STP settings. However, once you begin to
define a VLAN, you can no longer configure standard STP parameters globally using the CLI. From
that point on, you can configure STP only within individual VLANs.
To enable STP for all ports in all VLANs on a device, enter the following command.
PowerConnect(config)#spanning-tree
This command enables a separate spanning tree in each VLAN, including the default VLAN.
Syntax: [no] spanning-tree
TABLE 23 Default STP port parameters
Parameter Description Default and valid values
Priority The preference that STP gives this port relative to other
ports for forwarding traffic out of the spanning tree.
A higher numerical value means a lower priority.
128
Possible values in
PowerConnect B-Series TI24X
(configurable in increments of
16)
Path Cost The cost of using the port to reach the root bridge. When
selecting among multiple links to the root bridge, STP
chooses the link with the lowest path cost and blocks the
other paths. Each port type has its own default STP path
cost.
10 Mbps – 100
100 Mbps – 19
Gbps – 4
10 Gbps – 2
Possible values are 0 – 65535