R3721-F3210-F3171-HP High-End Firewalls Network Management Configuration Guide-6PW101

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NOTE:
• To globally enable or disable the spanning tree feature, use the stp enable command or undo stp
enable command in system view. To enable or disable the spannin
g
tree feature for specific VLANs, use
the stp vlan enable command or undo stp vlan enable command.
• You can disable the spanning tree feature for certain ports with the undo stp enable command to
exclude them from spanning tree calculation and save CPU resources of the device.
Performing mCheck
If a port on a device running MSTP or RSTP connects to an STP device, this port will automatically
transition to the STP-compatible mode. However, it cannot automatically transition back to the original
mode when:
• The STP device is shut down or removed.
• The STP device transitions to the MSTP or RSTP mode.
To forcibly transition the port to operate in the original mode, you can perform an mCheck operation.
The following methods for performing mCheck produce the same result.
1. Performing mCheck globally
To perform global mCheck:
Ste
p
Command
1. Enter system view.
system-view
2. Perform mCheck. stp mcheck
2. Performing mCheck in interface view
To perform mCheck in interface view:
Ste
p
Command
1. Enter system view.
system-view
2. Enter Ethernet interface view or Layer 2
aggregate interface view.
interface interface-type interface-number
3. Perform mCheck. stp mcheck
NOTE:
A
n mCheck operation takes effect on a device that operates in MSTP or RSTP mode.
Configuring Digest Snooping
As defined in IEEE 802.1s, interconnected devices are in the same region only when their MST
region-related configurations (region name, revision level, and VLAN-to-instance mappings) are
identical. A spanning tree device identifies devices in the same MST region by checking the configuration
ID in BPDU packets. The configuration ID includes the region name, revision level, and configuration
digest that is in 16-byte length and is the result calculated via the HMAC-MD5 algorithm based on
VLAN-to-instance mappings.