IIS is the Web server that hosts Communicator Web Access. Both IIS 6.0 and IIS 7.0 (running in IIS 6.0 compatibility mode) are supported for the 2007 R2 version of Communicator Web Access. If you use IIS 7.0 with Communicator Web Access, you must enable several IIS 7.0 features.

Communicator Web Access supports any combination of internal and external virtual server instances on the same or different computers.

The IIS queue length setting affects user capacity for Communicator Web Access.

You can optimize IIS 6.0 scalability and the user limit to increase capacity.

For details about Communicator Web Access components and capacity, see Capacity Planningand Communicator Web Access Support.