In the MSTP domain, multiple spanning trees can be generated based on instance calculations, and each spanning tree is called an MSTI. Which of the following statements about MSTI is correct?…

Question

Options

• AEach MSTI can share parameters to calculate its own spanning tree
• BThe role and status of each port on different MSTIs can be different
• CThe calculation of MSTIs depends on the VLAN mapping and different topologies
• DThe spanning tree parameters of each port on different MSTIs can be different

• A
  30% (13)
• B
  70% (31)

Explanation

B, C, and D are correct because MSTP is specifically designed to give each MSTI independent control: a port can be a Root Port on MSTI 1 and an Alternate Port on MSTI 2 simultaneously (B), each MSTI's topology is derived from its specific VLAN-to-instance mapping and the resulting network topology for those VLANs (C), and each port maintains per-instance parameters like port priority and path cost, enabling load balancing across instances (D).

A is wrong because each MSTI does not share parameters with other MSTIs - each instance holds its own independent bridge priority and port costs for its own calculation. The word "share" is the trap: MSTIs are isolated from each other's parameters by design, which is the whole point of running multiple trees.

Memory tip: Think of each MSTI as a separate city with its own traffic laws (parameters) and road maps (topology). A single intersection (port) can be a main road in one city and a side street in another - same physical port, different roles per instance. The city boundaries are drawn by VLAN mapping.

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