Cisco 2100 Series, Configuration Manual

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Cisco Wireless LAN Controller Configuration Guide
OL-17037-01
Chapter 3 Configuring Ports and Interfaces
Configuring Ports
When two ports on a controller are part of a loop, the spanning-tree port priority and path cost settings
determine which port is put in the forwarding state and which is put in the blocking state. The port
priority value represents the location of a port in the network topology and how well it is located to pass
traffic. The path cost value represents media speed.
The controller maintains a separate spanning-tree instance for each active VLAN configured on it. A
bridge ID, consisting of the bridge priority and the controller’s MAC address, is associated with each
instance. For each VLAN, the controller with the lowest controller ID becomes the spanning-tree root
for that VLAN.
STP is disabled for the controller’s distribution system ports by default. The following sections provide
instructions for configuring STP for your controller using either the GUI or CLI.
Note
STP cannot be configured for the controller in the Catalyst 3750G Integrated Wireless LAN Controller
Switch.
Using the GUI to Configure Spanning Tree Protocol
Follow these steps to configure STP using the GUI.
Step 1 Click Controller > Ports to open the Ports page (see Figure 3-8 ).
Step 2
Click the number of the port for which you want to configure STP. The Port > Configure page appears
(see
Figure 3-9 ). This page shows the STP status of the port and enables you to configure STP
parameters.
Table 3-4 interprets the current STP status of the port.
Table 3-4 Port Spanning Tree Status
Parameter Description
STP Port ID The number of the port for which STP is enabled or disabled.
STP State The port’s current STP state. It controls the action that a port takes upon
receiving a frame.
Values: Disabled, Blocking, Listening, Learning, Forwarding, and
Broken
STP State Description
Disabled The port is not participating in spanning tree because the
port is shut down, the link is down, or STP is not enabled
for this port.
Blocking The port does not participate in frame forwarding.
Listening The first transitional state after the blocking state when
STP determines that the port should participate in frame
forwarding.
Learning The port prepares to participate in frame forwarding.
Forwarding The port forwards frames.
Broken The port is malfunctioning.
STP Port Designated Root The unique identifier of the root bridge in the configuration BPDUs.