A video conferencing bridge is a piece of hardware or imbedded firmware in a video conferencing CODEC or system. Similar to conference calling or three way calling on your cell phone, a video conferencing bridge connects more than 2 end points at one time. If you envision calling not more than four locations on a video conferencing call at one time, most manufactures offer a built-in MCU feature, (Multipoint Conferencing Unit), on a standalone video conferencing CODEC. This allows you to connect to four locations simultaneously including the host or main location. If you anticipate conferencing to more than two locations simultaneously on a weekly basis the MCU feature would yield a great benefit. Keep in mind that MCU feature requires more bandwidth at the host location or the location of the MCU.
Some manufactures have MCU firmware for a CODEC that will connect up to nine locations, however much more bandwidth is required. Additionally continuous presence may become an issue with a built-in 9 port bridge. Continuous presence simply means you can see all 9 locations simultaneously just like The Brady Bunch intro or Hollywood Squares. Some manufactures say they can do 9 locations at one time, but they fail to mention that only 4 locations are seen and the other five are on audio only. If a manufacturer offers 9 locations make sure you have continuous presence as an option.
For a very large enterprise or bridge Service Company a “fixed” video conferencing bridge is required. Fixed video conferencing bridges can connect anywhere from 20 to hundreds of locations simultaneously. Additionally you can have separate simultaneous meetings. For example if your fixed bridge has 20 ports you can have four separate meetings with five locations each in the morning and two separate meetings with ten locations each in the afternoon. Additionally, most fixed videoconferencing bridges can connect mobile devices and standard telephone connections. Large enterprises appreciate the power of a fixed video conferencing bridge as they have a profound return on investment through far less travel and a substantial increase in productivity.