Spanning-Tree Operation

802.1s Multiple Spanning Tree Protocol (MSTP)

Syntax: spanning-tree config-revision < revision-number>

This command configures the revision number you designate for the MST region in which you want the switch to reside. This setting must be the same for all switches residing in the same region. Use this setting to differentiate between region configurations in situations such as the following:

Changing configuration settings within a region where you want to track the configuration versions you use

Creating a new region from a subset of switches in a current region and want to maintain the same region name.

Using the pending option to maintain two different configuration options for the same physical region.

Note that this setting must be the same for all MSTP switches in the same MST region. (Range: 0 - 65535; Default: 0)

Note: This option is available only when the switch is configured for MSTP operation.

Syntax: spanning-tree max-hops < hop-count>

This command resets the number of hops allowed for BPDUs in an MST region. When an MSTP switch receives a BPDU, it decrements the hop-count setting the BPDU carries. If the hop- count reaches zero, the receiving switch drops the BPDU. Note that the switch does not change the message-age and maximum-age data carried in the BPDU as it moves through the MST region and is propagated to other regions. (Range: 1 - 40; Default: 20)

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