Scaling Web Conferencing

A variety of Communications Server 2007 components must be connected to an organization’s corporate LAN, perimeter network, and PBX to support large-scale Web conferencing. Although all of Communications Server 2007’s Web conferencing features can be run on a single physical server, conferences will be limited to users inside the organization’s intranet firewall, and such a topology will probably not scale for large organizations. More complex Communications Server 2007 topologies allow for redundancy and scalability, support workers outside of the organization’s firewall, and allow conference leaders to control a remote teleconference bridge.

To improve scalability and fault tolerance, many Web conferencing components can be isolated and run on different physical servers and additional servers can be added to meet demand. Among other services, the front end servers (pictured at the top center in the illustration) provide conference setup, authentication, and tracking and management of conference state. Communications Server 2007 also requires Internet Information Services running on each Front End server or on separate servers (shown as Web servers in the illustration). A hardware load balancer (such as F5’s BIG-IP) must be installed in configurations with multiple Front End servers and Web servers (Front End and Web servers can use separate or, as shown, the same load balancer). The Live Meeting 2007 client uses the Web servers to download meeting content, such as PowerPoint presentations. Similarly, the Audio and Video (A/V) server can run on the Front End servers or separately, as can the Web Conferencing server, which manages the exchange of data other than audio and video to support features such as desktop sharing, meeting Q&A, and polling.