MSTP Key Characteristic

D.

MSTP stands for Multiple Spanning Tree Protocol. It is a protocol that enables multiple VLANs to be mapped to a single spanning-tree instance, reducing the number of spanning-tree instances required in a network.

The correct answer to the question is D - "several VLANs can be mapped to the same spanning-tree instance."

MSTP is an IEEE 802.1s standard, which was created to address the limitations of the original IEEE 802.1D STP (Spanning Tree Protocol) standard. One of the limitations of 802.1D is that it only allows for a single spanning-tree instance per VLAN. This means that in a network with many VLANs, there can be a large number of spanning-tree instances, which can consume a significant amount of network resources.

MSTP allows for multiple VLANs to be mapped to a single spanning-tree instance, which reduces the number of spanning-tree instances required in the network. This is accomplished by grouping VLANs into regions, which share the same spanning-tree instance. Each region has a unique MSTP configuration, which allows for the use of multiple spanning-tree instances in the network.

In addition to reducing the number of spanning-tree instances required, MSTP also provides a faster convergence time than 802.1D. This is because MSTP can detect changes in the network topology more quickly and accurately, and can recalculate the spanning-tree paths more efficiently.

In summary, the key characteristic of MSTP is that it allows several VLANs to be mapped to the same spanning-tree instance, reducing the number of spanning-tree instances required in the network.