Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 254)

Default STP port parameters TABLE 45
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: 0 - 240 (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
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.
Configuration modes for STP
The following configuration modes apply while configuring STP.
• Spanning-tree single - This configuration can be enabled on systems running IEEE 802.1D. The
single spanning tree controls all the 4000 VLANs. You can opt in and out of this single spanning
tree using the spanning-tree command under the VLAN prompt.
• Spanning-tree single 802.1w - This configuration can be enabled on systems running IEEE 802.1w.
The single rapid spanning tree controls all the 4000 VLANs. The VLAN can opt in and out of this
single rapid spanning tree using the spanning-tree command under the VLAN prompt. If there is a
“spanning-tree” configuration under the VLAN, that VLAN will be with that single 802.1w instance’s
control, which implies that the VLAN traffic is subject to blocking or forwarding by that spanning tree
instance.
• Per VLAN spanning tree - In this configuration mode you can turn on 802.1D or 802.1w (Rapid
Spanning Tree) at the VLAN level individually.
Enabling or disabling the Spanning Tree Protocol (STP)
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