Multiple Instance Spanning-Tree Operation

802.1s Multiple Spanning Tree Protocol (MSTP)

Displaying the Region-Level Configuration in Brief. This command output is useful for quickly verifying the allocation of VLANs in the switch’s MSTP configuration and for viewing the configured region identifiers.

Syntax: show spanning-tree mst-config

This command displays the switch’s regional configuration.

Note: The switch computes the MSTP Configuration Digest from the VID to MSTI configuration mappings on the switch itself. As required by the 802.1s standard, all MSTP switches within the same region must have the same VID to MSTI assignments, and any given VID can be assigned to either the IST or one of the MSTIs within the region. Thus, the MSTP Configuration Digest must be identical for all MSTP switches intended to belong to the same region. When comparing two MSTP switches, if their Digest identifiers do not match, then they cannot be members of the same region.

Refer to the “Note”, above.

Figure 5-15. Example of a Region-Level Configuration Display

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