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| Chapter 13 Spanning Tree Protocol |
| Table 31 Advanced Application > Spanning Tree Protocol > MRSTP (continued) | |
| LABEL | DESCRIPTION |
| Bridge Priority | Bridge priority is used in determining the root switch, root port and |
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| designated port. The switch with the highest priority (lowest numeric |
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| value) becomes the STP root switch. If all switches have the same |
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| priority, the switch with the lowest MAC address will then become the |
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| root switch. Select a value from the |
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| The lower the numeric value you assign, the higher the priority for this |
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| bridge. |
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| Bridge Priority determines the root bridge, which in turn determines |
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| Hello Time, Max Age and Forwarding Delay. |
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| Hello Time | This is the time interval in seconds between BPDU (Bridge Protocol Data |
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| Units) configuration message generations by the root switch. The |
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| allowed range is 1 to 10 seconds. |
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| Max Age | This is the maximum time (in seconds) a switch can wait without |
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| receiving a BPDU before attempting to reconfigure. All switch ports |
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| (except for designated ports) should receive BPDUs at regular intervals. |
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| Any port that ages out STP information (provided in the last BPDU) |
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| becomes the designated port for the attached LAN. If it is a root port, a |
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| new root port is selected from among the Switch ports attached to the |
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| network. The allowed range is 6 to 40 seconds. |
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| Forwarding | This is the maximum time (in seconds) a switch will wait before |
| Delay | changing states. This delay is required because every switch must |
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| receive information about topology changes before it starts to forward |
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| frames. In addition, each port needs time to listen for conflicting |
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| information that would make it return to a blocking state; otherwise, |
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| temporary data loops might result. The allowed range is 4 to 30 |
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| seconds. |
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| As a general rule: |
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| Note: 2 * (Forward Delay - 1) >= Max Age >= 2 * (Hello Time + 1) |
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| Port | This field displays the port number. |
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| * | Settings in this row apply to all ports. |
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| Use this row only if you want to make some settings the same for all |
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| ports. Use this row first to set the common settings and then make |
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| adjustments on a |
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| Note: Changes in this row are copied to all the ports as soon as you |
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| make them. |
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| Active | Select this check box to activate STP on this port. |
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| Edge | Select this check box to configure a port as an edge port when it is |
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| directly attached to a computer. An edge port changes its initial STP |
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| port state from blocking state to forwarding state immediately without |
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| going through listening and learning states right after the port is |
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| configured as an edge port or when its link status changes. |
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| Note: An edge port becomes a |
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| a Bridge Protocol Data Unit (BPDU). |
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| 159 |
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