Communicator Web Access is an extension of Office Communications Server that enables IM, presence, desktop sharing, and audio features on Web-based clients. This enables computers that don’t have unified communications client software installed to benefit from Office Communications Server features, without the need to download additional software. The client computers can run Windows-based, Macintosh, or Linux operating systems, and they can be either inside or outside of your organization’s firewall.
To enable Communicator Web Access, you deploy one or more Communicator Web Access servers in your internal network. We recommend that you deploy at least two servers, one for internal users and another for remote users. This enhances the security and availability of the feature; if any issue arises that causes the need for you to shut down the Communicator Web Access server for external users, internal users are not affected.
If you have scaling needs, you can deploy an array of Communicator Web Access servers behind a load balancer for internal users, external users, or both.
Both internal and external users connect to Communicator Web Access by entering a URI, such as https://extusers.contoso.com, in their Web browser. The Communicator Web Access server performs authentication and authorization before it forwards the traffic to the Enterprise pool to provide presence and IM.
Remote users can sign in to Communicator Web Access through the SSL-based external URI, which is published to the Web by a reverse proxy server. Communicator Web Access supports any firewall or reverse proxy configuration for creating a perimeter network, including Microsoft Internet Security and Acceleration (ISA) Server.