Chapter 13 Spanning Tree Protocol
Table 29 Advanced Application > Spanning Tree Protocol > MRSTP (continued)
LABEL | DESCRIPTION |
Bridge Priority | Bridge priority is used in determining the root switch, root port and |
| designated port. The switch with the highest priority (lowest numeric |
| value) becomes the STP root switch. If all switches have the same |
| priority, the switch with the lowest MAC address will then become the |
| root switch. Select a value from the |
| The lower the numeric value you assign, the higher the priority for this |
| bridge. |
| Bridge Priority determines the root bridge, which in turn determines |
| Hello Time, Max Age and Forwarding Delay. |
|
|
Hello Time | This is the time interval in seconds between BPDU (Bridge Protocol Data |
| Units) configuration message generations by the root switch. The |
| allowed range is 1 to 10 seconds. |
|
|
Max Age | This is the maximum time (in seconds) the Switch can wait without |
| receiving a BPDU before attempting to reconfigure. All Switch ports |
| (except for designated ports) should receive BPDUs at regular intervals. |
| Any port that ages out STP information (provided in the last BPDU) |
| becomes the designated port for the attached LAN. If it is a root port, a |
| new root port is selected from among the Switch ports attached to the |
| network. The allowed range is 6 to 40 seconds. |
|
|
Forwarding | This is the maximum time (in seconds) the Switch will wait before |
Delay | changing states. This delay is required because every switch must |
| receive information about topology changes before it starts to forward |
| frames. In addition, each port needs time to listen for conflicting |
| information that would make it return to a blocking state; otherwise, |
| temporary data loops might result. The allowed range is 4 to 30 |
| seconds. |
| As a general rule: |
| Note: 2 * (Forward Delay - 1) >= Max Age >= 2 * (Hello Time + 1) |
|
|
Port | This field displays the port number. |
|
|
* | Settings in this row apply to all ports. |
| Use this row only if you want to make some settings the same for all |
| ports. Use this row first to set the common settings and then make |
| adjustments on a |
| Note: Changes in this row are copied to all the ports as soon as you |
| make them. |
|
|
Active | Select this check box to activate STP on this port. |
|
|
Priority | Configure the priority for each port here. |
| Priority decides which port should be disabled when more than one port |
| forms a loop in a switch. Ports with a higher priority numeric value are |
| disabled first. The allowed range is between 0 and 255 and the default |
| value is 128. |
|
|
Path Cost | Path cost is the cost of transmitting a frame on to a LAN through that |
| port. It is recommended to assign this value according to the speed of |
| the bridge. The slower the media, the higher the cost - see Table 24 on |
| page 126 for more information. |
138 |
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