Cisco Certified Network Professional Practice Test 2025 - Free CCNP Exam Practice Questions and Study Guide

Including a password in VLAN Trunking Protocol (VTP) configurations serves to restrict access to the VTP domain. When a password is configured, only switches that share the same VTP domain name and the correct password can participate in VTP operations. This enhances security by preventing unauthorized switches from sending or receiving VTP advertisements, thus protecting the VLAN configuration and integrity of the network.

This is particularly important in environments where multiple administrators or third-party devices may have access, as an unauthorized switch could potentially disrupt or interfere with VLAN configurations. By requiring a password, network administrators ensure that only trusted devices can make changes or updates to the VLAN information within the VTP domain, helping maintain network stability and security.

The other options focus on aspects that aren't related to the primary function of VTP passwords; for instance, while encryption of VLAN IDs is a security measure, it isn't a direct function of VTP passwords. Similarly, while VTP can affect advertisement efficiency, the inclusion of a password does not enhance this process, nor does it serve to store VLAN configurations securely.