Map Magazine Subscriptions Article Index Contact Info FAQ Free Newsletters Corporate. There's a fundamental difference between transmitting a videoconference over ISDN and over an IP network. ISDN connections are clean and steady, while IP is bursting with variable delays. Outside the LAN, IP packets travel through gateways and routers on the Internet, which introduce transit delays.
People are somewhat tolerant of video degradation.
Audio is another story. Video can be up to 95 ms delay, plus variance, before frame-freezing sets in. W hile testing the Intel and PictureTel systems, we ping-tested in the San Mateo, Calif., lab and measured only 8 ms to 10 ms delays. When testing between San Mateo and the University of Wisconsin lab on our frame relay network, delays varied between 85 ms and 120 ms. Audio and video quality remained acceptable.