As shown in the figure, four Huawei switches have been running and configured with the MSTP protocol. Now SW3 needs to be set as the root bridge of Instance 10. SW1, SW2, SW3, SW4 Configuration: stp…

Question

Options

• Astp vlan 10 root primary
• Bstp instance 10 priority 4096
• Cstp root primary
• Dstp instance 10 root primary

• A
  6% (3)
• B
  4% (2)
• C
  19% (9)
• D
  70% (33)

Explanation

Option D is correct because MSTP operates on instances, and the proper Huawei syntax to designate a root bridge for a specific instance is stp instance <id> root primary, which automatically sets the bridge priority to 0 to guarantee root election for that instance. Option A uses vlan 10 instead of instance 10, which is PVST-style syntax not applicable to MSTP - in MSTP, VLANs are mapped to instances, so commands target the instance, not the VLAN directly. Option B (stp instance 10 priority 4096) sets a lower priority but does not guarantee root election because another switch could have an equal or lower priority value, making it unreliable. Option C (stp root primary) lacks the instance specification, so it does not correctly target instance 10 in an MSTP environment.

Memory tip: In MSTP, always think "instance, not VLAN" - even though instance 10 maps to VLAN 10, every MSTP command references the instance number. Pair that with root primary to guarantee the win, and you will always land on the correct syntax.

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