In Lync Server 2013, the architecture of a large Enterprise Edition deployment has become much simpler. There are no Archiving, Monitoring, or A/V Conferencing Servers to deploy because all are now collocated and Director is now officially an optional role. In a large virtualized deployment, you scale to four host servers and split out the SQL for Monitoring and Archiving to a dedicated virtual machine for performance reasons. At this scale it is likely Office Web Apps servers would have their own dedicated infrastructure. Although Directors are optional, they have been included because typically they are required for security reasons at this scale of deployment. This architecture is shown in Figure 29.7.