Table Of Contents
Spanning Tree Settings
(Switch > Spanning Tree)
Configuring STP Settings for All VLANs
Editing STP Settings for a VLAN or VLANs
Configuring STP Settings for a Specific VLAN
Editing STP Settings for a Specific VLAN
Configuring STP Settings for All Ports
Editing STP Settings for a Port or Ports
Configuring STP Settings for a Specific Port
Editing STP Settings For a Specific Port
Spanning Tree Settings
(Switch > Spanning Tree)
CVDM-C6500 allows you to view and configure VLAN and port spanning tree protocol (STP) settings. STP is a link management protocol that provides path redundancy while preventing undesirable loops in the network. For a Layer 2 Ethernet or Token Ring network to function properly, only one active path can exist between two stations. STP operation is transparent to end stations, which cannot detect whether they are connected to a single LAN segment or a switched LAN of multiple segments.
For more information about configuring STP, see the relevant section in the Catalyst 6500 Family IOS Software Configuration Guide.
Note 
You can configure global STP settings from the Global STP Settings page. For more information, see Configuring Global STP Settings.
The following topics contain information about:
•Configuring STP Settings for All VLANs
•Configuring STP Settings for a Specific VLAN
•Configuring STP Settings for All Ports
•Configuring STP Settings for a Specific Port
Configuring STP Settings for All VLANs
You can view your STP settings for all VLANs. Click Switch at the top of the window, click Spanning Tree in the left-most pane, and select VLANs in the selector to display the Spanning Tree page (see Figure 5-1).
Figure 5-1 STP Page
This page provides a table that displays the following information:
Column
|
Description
|
VLAN
|
Number (ID) of the VLAN.
|
STP Status
|
Status (enabled or disabled) of STP on the VLAN.
|
Primary Root
|
Specifies if the VLAN is on a primary root switch (yes or no).
|
Ports column
|
Contains the following sub-columns:
•Blocking—Number of blocking ports.
Ports in the blocking state do not participate in frame forwarding. A switch always enters the blocking state after switch initialization.
•Listening—Number of listening ports.
Ports enter the listening state when STP determines that the port should participate in frame forwarding. Ports enter the listening state from the blocking state. Learning is disabled in the listening state.
•Learning—Number of learning ports.
Ports in the learning state prepare to participate in frame forwarding. Ports enter the learning state from the listening state.
•Forwarding—Number of forwarding ports.
Ports in the forwarding state forward frames. Ports enter the forwarding state from the learning state.
•STP Active—Total number of blocking, listening, learning, and forwarding VLANs.
|
|
Note CVDM-C6500 supports only PVST and Rapid PVST STP modes. You can change your STP mode from the Global Settings page (for more information, see Configuring Global Settings). However, if you select MST as the STP mode, then CVDM-C6500 does not populate any STP data.
You can edit your STP settings for a VLAN or VLANs from this page. For more information, see Editing STP Settings for a VLAN or VLANs.
Editing STP Settings for a VLAN or VLANs
Step 1 Click Switch at the top of the window, click Spanning Tree in the left-most pane, and select VLANs from the selector.
Step 2 From the table, select the VLAN you want to edit. To select multiple VLANs, press the Ctrl key as you select each VLAN you want to edit.
Step 3 Click Edit... The Edit STP Settings dialog box appears.
Step 4 Edit the appropriate values.
GUI Element
|
Action/Description
|
VLAN Range field
|
Values (IDs) of the VLAN(s) that you want to edit. You cannot edit this field.
|
Enable STP list
|
Select if you want to enable STP (yes or no) on the VLAN or VLANs.
|
Root Configuration list
|
Select the root configuration (Primary, Secondary, or Not Root).
|
Step 5 Click Deliver at the top of the window. For more information on delivering accumulated CLI commands, see Delivering CLI Commands to the Device.
Configuring STP Settings for a Specific VLAN
You can view your STP settings for a particular VLAN. Click Switch at the top of the window, click Spanning Tree from the left-most pane, and select VLANs from the selector. Then, from the selector, select the VLAN for which you want to view your STP settings. The following information is displayed:
GUI Element
|
Description
|
STP Summary pane
|
VLAN field
|
Number (ID) of the VLAN.
|
Protocol field
|
Protocol.
|
STP Status field
|
Status (enabled or disabled) of STP.
|
Root Switch field
|
Specifies if the switch is a root (yes or no).
The STP root switch is the logical center of the STP topology in a switched network.
|
Root Cost field
|
Also called Root Path Cost—the cumulative cost of all links to the root bridge.
In a BPDU, this is the value transmitted in the cost field. In a bridge, this value is calculated by adding the receiving port's path cost to the value contained in the BPDU.
|
Root Port field
|
Specifies the port that is closest to the root bridge. Every nonroot bridge must select one root port.
|
Bridge Priority field
|
Priority value of the bridge. The value can be from 1 to 65535.
|
MAC Address field
|
MAC address of this switch.
|
Hello Time field
(seconds)
|
Determines how often the root switch broadcasts its hello message to other switches.
|
Max Age field
(seconds)
|
Measures the age of the received protocol information recorded for a port and ensures that this information is discarded when its age limit exceeds the value of the maximum age parameter recorded by the switch. The timeout value is the maximum age parameter of the switches.
|
Forward Delay field
(seconds)
|
Monitors the time spent by a port in the learning and listening states. The timeout value is the forward delay parameter of the switches.
|
Root Bridge pane
|
Bridge Priority field
|
Priority value of the root bridge. The value can be from 1 to 65535.
|
MAC Address field
|
MAC address of the root bridge.
|
Hello Time field
(seconds)
|
Determines how often the switch broadcasts its hello message to other switches.
|
Max Age field
(seconds)
|
Measures the age of the received protocol information recorded for a port and ensures that this information is discarded when its age limit exceeds the value of the maximum age parameter recorded by the switch. The timeout value is the maximum age parameter of the switches.
|
Forward Delay field
|
Monitors the time spent by a port in the learning and listening states. The timeout value is the forward delay parameter of the switches.
|
Ports table
|
Interface column
|
Names of the access and trunk ports associated with this VLAN.
|
Role column
|
STP-assigned role; STP works by assigning roles to switches and ports to ensure that there is only one path through the switched network at any one time. The roles assigned are root bridge, root port, designated port, and nondesignated port.
There is only one root bridge in any loop and only one designated port in any one segment. On the root bridge, all ports are designated. The selection of the root bridge is based on either an assigned number or an arbitrary number such as a MAC address.
|
Status column
|
Status (blocking, learning, listening, or forwarding) of the port on this VLAN.
|
Cost column
|
Port cost value; ports with lower port costs are more likely to be chosen to forward frames.
|
Priority column
|
Port priority value; the port with the lowest priority value forwards frames for all VLANs.
|
Number column
|
Port number; if all ports have the same port priority value, STP puts the port with the lowest port number in the forwarding states and blocks other ports.
|
Link Type column
|
Link type on the port (Shared or Point-to-point):
•Shared indicates that the link is a shared segment and can contain more than one device.
•Point-to-point indicates that the link is a point-to-point link to another device.
|
From this page, you can edit your STP settings for a VLAN. See Editing STP Settings for a Specific VLAN for more information.
Editing STP Settings for a Specific VLAN
Step 1 Click Switch at the top of the window, click Spanning Tree from the left-most pane, and select VLANs from the selector. Then, from the selector, select the VLAN for which you want to edit STP settings.
Step 2 From the Edit STP Settings pane, select the Edit button. The Edit STP Settings dialog box appears.
Step 3 Edit the appropriate values.
GUI Element
|
Action/Description
|
VLAN Number field
|
Number (ID) of the VLAN. You cannot edit this field.
|
Enable STP check box
|
Click the check box to enable STP on the VLAN.
|
Root Config radio button
|
Specify the configuration of the root. Do one of the following:
•Select the via Macro radio button and select the root type (Primary, Secondary, Not Root) from the Root Type list.
Macro looks at the bridge priority value of all other switches and compares it to the value of this switch; to make this switch the root switch, Macro gives this switch a lower value to force it to become the root.
•Select the via Bridge Priority radio button and specify the bridge priority. Do one of the following:
–If Extended System ID is enabled, the Bridge Priority list is shown; select the bridge priority value from this list.
–If Extended System ID is disabled, enter any bridge priority value from 1 to 65535 in the Bridge Priority field.
You can configure Extended System ID settings from the Global STP Settings page. For more information, see Configuring Global STP Settings.
The switch becomes the root when its bridge priority value is the lowest value.
If the bridge priority value of this switch is the same as the bridge priority value of another switch, the switch with the lower MAC address becomes the root switch.
|
Step 4 Click Deliver at the top of the window. For more information on delivering accumulated CLI commands, see Delivering CLI Commands to the Device.
Configuring STP Settings for All Ports
You can view your STP settings for all ports. Click Switch at the top of the window, click Spanning Tree in the left-most pane, and select Ports from the selector. The following information is displayed:
Column
|
Description
|
Port Name
|
Name of the port.
|
PortFast
|
Indicates the status of PortFast (Enabled, Disabled, or Global) on the port.
PortFast causes a port to immediately enter the spanning-tree forwarding state, bypassing the listening and learning states.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
VLANs
|
Contains the following sub-columns:
•Blocking VLANs—Number of VLANs on which the port is blocking.
•Listening VLANs—Number of VLANs on which the port is listening.
•Learning VLANs—Number of VLANs on which the port is learning.
•Forwarding VLANs—Number of VLANs on which the port is forwarding.
|
You can edit your STP settings for a port or ports from this page. See Editing STP Settings for a Port or Ports for more information.
Editing STP Settings for a Port or Ports
Step 1 Click Switch at the top of the window, select Spanning Tree in the left-most pane, and select Ports from the selector.
Step 2 From the table, select the port you want to edit. To select multiple ports, press the Ctrl key as you select each ports you want to edit.
Step 3 Click the Edit... button. The Edit STP Settings dialog box appears.
Step 4 Edit the appropriate values.
GUI Element
|
Action/Description
|
Port(s) field
|
Name of the port(s) that you want to edit. You cannot edit this field.
|
Enable PortFast list
|
Select the status of PortFast (Enabled, Disabled, or Global) on the port.
PortFast causes a port to immediately enter the spanning-tree forwarding state, bypassing the listening and learning states.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
Step 5 Click Deliver at the top of the window. For more information on delivering accumulated CLI commands, see Delivering CLI Commands to the Device.
Configuring STP Settings for a Specific Port
You can view your STP settings for a particular port. Click Switch at the top of the window, click Spanning Tree in the left-most pane, and select Ports from the selector. Then, select the port for which you want to view STP settings. The following information is provided:
GUI Element
|
Description
|
STP Summary pane
|
Name field
|
Name of the port.
|
Port Cost field
|
Port cost value; ports with lower port costs are more likely to be chosen to forward frames. If the port does not have a port cost value in the device running configuration, default is displayed.
|
Port Priority field
|
Port priority value; the port with the lowest priority value forwards frames for all VLANs. If the port does not have a port priority value, default is displayed.
|
Link Type field
|
Link type on the port (Shared, Point-to-point, or Default):
•Shared indicates that the link is a shared segment and can contain more than one device.
•Point-to-point indicates that the link is a point-to-point link to another device.
|
PortFast field
|
Status (Enabled, Disabled, or Global) or PortFast.
PortFast causes a port to immediately enter the spanning-tree forwarding state, bypassing the listening and learning states.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
BPDU Guard field
|
Status (Enabled, Disabled, or Global) of BPDU guarding.
When enabled, BPDU guard causes STP to shut down PortFast-configured interfaces that receive BPDUs, instead of putting them into the spanning-tree blocking state.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
BPDU Filter field
|
Status (Enabled, Disabled, or Global) of BPDU filtering.
When enabled, the BPDU filter allows you to avoid transmitting BPDUs on PortFast-enabled ports that are connected to an end system.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
Guard field
|
Type of guard enabled on the port. Values can be:
•Loop—Verifies whether or not a root port or an alternate root port receives BPDUs. If the port is not receiving BPDUs, the loop guard feature puts the port into an inconsistent state until it starts receiving BPDUs again.
•Root—Forces a Layer 2 LAN interface to become a designated port; if any device accessible through the interface becomes the root bridge, root guard puts the interface into the blocked state.
•None—No guarding is enabled On the port.
•Global—Value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
STP VLAN Summary table
|
VLAN Number column
|
Number (ID) of the VLAN to which the port belongs.
|
Status column
|
Status (blocking, learning, listening, or forwarding) of the port on this VLAN.
|
Role column
|
STP-assigned role; STP works by assigning roles to switches and ports to ensure that there is only one path through the switched network at any one time. The roles assigned are root bridge, root port, designated port, and nondesignated port.
There is only one root bridge in any loop and only one designated port in any one segment. On the root bridge, all ports are designated. The selection of the root bridge is based on either an assigned number or an arbitrary number such as a MAC address.
|
Cost column
|
Cost value on this VLAN; ports with lower port-VLAN costs are more likely to be chosen to forward frames. This value takes precedence over the global port cost value (displayed in the STP Summary Pane).
|
Priority column
|
Port priority value on this VLAN; the port with the lowest priority value forwards frames for all VLANs. This value takes precedence over the global port priority value (displayed in the STP Summary Pane).
|
You can edit your STP settings for a port from this page. See Editing STP Settings For a Specific Port for more information.
Editing STP Settings For a Specific Port
Step 1 Click Switch at the top of the window, click Spanning Tree in the left-most pane, and select Ports from the selector. Then, from the selector, select the port for which you want to configure STP settings.
Step 2 From the STP Summary field, click the Edit button. The Edit STP Settings dialog box appears.
Step 3 Edit the appropriate values.
GUI Element
|
Action/Description
|
Port Cost field
|
Enter the port cost value.
Ports with lower port costs are more likely to be chosen to forward frames.
|
Port Priority list
|
Select the port priority value.
The port with the lowest priority value forwards frames for all VLANs.
|
Link Type list
|
Select the link type on the port (Shared, Point-to-point, or Default):
•Shared indicates that the link is a shared segment and can contain more than one device.
•Point-to-point indicates that the link is a point-to-point link to another device.
|
PortFast list
|
Select the status of PortFast (Enabled, Disabled, or Global) on the port.
When enabled, PortFast causes a switch or trunk port to immediately enter the STP forwarding state, bypassing the listening and learning states.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
BPDU Guard list
|
Select the status of BPDU guard (Enabled, Disabled, or Global) on the port.
When enabled, BPDU guard causes STP to shut down PortFast-configured interfaces that receive bridge protocol data units (BPDUs), instead of putting them into the spanning-tree blocking state.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
BPDU Filter list
|
Select the status of BPDU filter (Enabled, Disabled, or Global) on the port.
When enabled, BPDU filter allows you to avoid transmitting BPDUs on PortFast-enabled ports that are connected to an end system.
Note The Global value is the value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
STP Guard list
|
Select the type of STP guard (None, Root, Loop, or Global).
•Loop—Verifies whether or not a root port or an alternate root port receives BPDUs. If the port is not receiving BPDUs, the loop guard feature puts the port into an inconsistent state until it starts receiving BPDUs again.
•Root—Forces a Layer 2 LAN interface to become a designated port; if any device accessible through the interface becomes the root bridge, root guard puts the interface into the blocked state.
•None—No guarding is enabled on the port.
•Global—Value specified in the Global STP Settings page. For more information, see Configuring Global STP Settings.
|
Step 4 Click Deliver at the top of the window. For more information on delivering accumulated CLI commands, see Delivering CLI Commands to the Device.
