Cascading is a technique for connecting videoconferencing systems together, so that more sites can join in a meeting. With TANDBERG videoconferencing systems, for example, up to 10 video sites and 4 audio sites can be connected in a single call. The sites can be connected by ISDN, IP or both networks in the same call. 14 sites can be connected if the sites use audio only. The main advantage of cascading a videoconference is that is eliminates the need to use an external bridging service.