MSTP Configuration Elements

BD

The correct answer is B, D because revision-level is common for the all MSTI instances and it is configured one level up from MSTI instance section.

MSTP (Multiple Spanning Tree Protocol) is a standard-based protocol that provides loop-free paths and redundancy in switched networks. An MSTP instance is a logical entity that runs MSTP protocol and represents a set of VLANs that share the same spanning tree topology.

The configuration elements that can be defined under an MSTP instance are:

A. revision-level: MSTP uses a revision number to maintain backward compatibility with the older version of the protocol. When a switch receives a BPDU (Bridge Protocol Data Unit) from another switch, it compares the revision number in the BPDU with its own revision number. If the received revision number is higher, the switch updates its own revision number and re-calculates the spanning tree topology. The revision level is used to manage the MSTP instances and to prevent loops in the network.

B. bridge-priority: The bridge priority is a value that is used to elect the root bridge in the spanning tree topology. The root bridge is the switch that has the lowest bridge priority value. The bridge priority can be set for each switch in the network, and it is used to influence the path that traffic takes through the network.

C. mstp-level: MSTP supports multiple spanning tree instances on a per-VLAN basis. The mstp-level configuration element is used to assign a VLAN to a specific instance. Each instance has a separate spanning tree topology, and the traffic for each VLAN is mapped to the corresponding instance.

D. vlan: The VLAN configuration element defines the set of VLANs that belong to the MSTP instance. All switches that participate in the MSTP instance must have the same set of VLANs defined in their configuration.

Therefore, the correct answer for the two configuration elements that are defined under an MSTP instance is A. revision-level and B. bridge-priority.