The optional designation doesn’t mean a Director should always be excluded from deployments—in fact, it still makes sense to deploy Directors in many cases. Organizations should review their own business requirements and consider the following points before making a decision on the Director pool deployment:
• Directors provide an additional layer of security from denial-of-service attacks at the Edge. Unauthenticated requests will never reach a Front End pool and affect internal users.
• Anonymous web traffic for Lync simple URLs such as
admin can be terminated at the Director’s web services.
• Directors provide centralized authentication and redirection for environments with multiple pools.
• Directors ...