When expanding an existing Lync environment there are several factors to consider.
- Are you expanding into a new department of people or sub organisation?
- Do the users want to communicate with the existing Lync users?
- Do you want the administrators to have separate controls?
At a recent deployment we harnessed the power of custom RBAC (role based administration) groups to provide Lync for an organisation that participates in a larger multi-tenanted Active Directory service. This enabled the local administrators to confidently manage their own estate whilst knowing they could not affect the operations of Lync users at other organisations.
With regards to topology, Microsoft Lync is incredibly flexible in harnessing segmentation and separation concepts with a flexible design model that allows expansion without full redesign.
Microsoft Lync proves that in this case, you can never have too much of a good thing.