Standard Edition Configuration

In a Standard Edition Configuration, a Front-End server hosts one or more Lync/Skype for Business Server services and the Back-End database. If you are using the Standard Edition Configuration, install IM Security on the same Front-End server that hosts the Lync/Skype for Business Server database and services.

Small to Medium Deployment Scenario

If your environment has fewer than 5,000 users, and you intend to utilize all of the Lync/Skype for Business Server services and allow external user access, you can deploy one IM Security protected Front-End server and one Access Edge server. Refer to the Microsoft Lync Server 2013/Skype for Business Server 2015 Planning Guide for more details and additional deployment scenarios.