Which authentication method is recommended for a small number of users?

Using local users as an authentication method is particularly recommended for a small number of users due to its simplicity and ease of management. Local user accounts are typically stored within the device itself, which means there is no need for additional external services or servers. This approach allows for quick and straightforward access control without the overhead of maintaining external authentication systems, making it ideal for smaller environments or organizations where the number of users is limited.

Moreover, local user authentication supports basic credential management, such as username and password combinations, which is sufficient when dealing with a limited user base. This method is also helpful in scenarios where users do not require complex or centralized access management features that are typically found in larger networks.

In contrast, options like RADIUS and LDAP are generally better suited for environments with a higher number of users, as they provide centralized authentication and can manage extensive user directories, which isn't necessary when the user count is low. The multicast option does not relate to authentication and is not an appropriate choice in this context.