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Configuring a Bridge Port

Web Agent Procedure

To configure a spanning tree bridge port:

  1. In the navigation pane, expand the L2 Switching folder.
  2. Click Spanning Tree.
  3. The Spanning Tree Information Web page is displayed in the content pane. See Figure�40.

  4. In the Bridge Ports field, click the bridge for which you want to configure a port.
  5. The Spanning Tree Per Module Bridge Port Information Web page is displayed in the content pane.

  6. In the Bridge Ports field, click the ports that you want to configure.
  7. The Spanning Tree Bridge Port Information Web page is displayed. See Figure�62.

  8. In the Bridge Port field, click the bridge port that you want to configure.
  9. The Spanning Tree Port Configuration Web page is displayed. See Figure�63.

Figure�63:�Spanning Tree Port Configuration Web Page


  1. Configure the bridge port as appropriate.
  2. Table�43 provides explanations of each field.

  3. Click APPLY to save your changes or CANCEL to restore the previous settings.

Table�43:�Spanning Tree Port Configuration Parameters �
Parameter
Definition
Priority
Priority of the port as a decimal value. A higher priority port (has a lower priority number) is more likely to be chosen as the primary path in the spanning tree when there are two or more paths of equal cost.
The valid range for this field is 0 to 240 in increments of 16. The default setting is 128.
Administrative Path Cost
Sets the path cost for this port. The ports that you prefer be used by the spanning tree should have the lowest path cost.
If the switch is running common Spanning Tree, the valid range for this field is 0 to 65535.
If the switch is running Rapid Spanning Tree, the valid range for this field is 0 to 200,000,000.
The default setting is 0. If this field is set to 0, the port uses the default path cost for the bridge.
Operational Path Cost
The path cost that Spanning Tree is using for the port:
  • If Administrative Path Cost is set to a nonzero value, this field displays that nonzero value.
  • If Administrative Path Cost is set to 0, the switch is running Rapid Spanning Tree, and Path Cost Default for the bridge is set to Rapid-spanning-tree, then this field displays the following values (recommended in Table 17-7 of IEEE Std. 802.1w-2001).
    • 10 Mbps port--2,000,000
    • 100 Mbps port--200,000
    • 1 Gbps port--20,000
    • 10 Gbps port--2,500
    • For hunt groups, this field displays the operational path cost of one link divided by the number of links in the hunt group. For example, if a hunt group comprises four 1-GB ports, and the operational path cost for one port is 20,000, the operational path cost for the hunt group is 5,000 (20,000 4).

  • If Administrative Path Cost is set to 0 and the switch is running common Spanning Tree, then this field displays the following values (regardless of the Path Cost Default setting):
    • For 10 MB ports, 100
    • For 100 MB ports, 19
    • For 1 GB ports, 4
    • For 10 GB ports, 3

Note: If the port is a trunk port (IEEE 802.1q or Multi-Layer tagging is enabled), the operational path cost is one less than the value in the preceding list.

For hunt groups, this field displays the operational path cost of one link minus 1. For example, if a hunt group comprises four 1-GB ports, and the operational path cost for one port is four, the operational path cost of the hunt group is 3 (4 - 1).

Force BPDU Migration
Clicking SEND RSTP BPDU in this field forces the bridge port to send out RSTP BPDUs. By forcing a bridge port to send RSTP BPDUs, you can determine whether legacy 802.1D bridges are present on a LAN segment.
If you remove a legacy 802.1D bridge from a segment, other RSTP bridges on the segment cannot detect the removal so they continue sending STP BPDUs. However, if you force a bridge port to send RSTP BPDUs, they trigger other RSTP bridges on the segment to generate RSTP BPDUs again.
If the switch is running common Spanning Tree, this command has no effect.


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