e outcome is limited by the statistical probability of network bits available for unknown peak program content payload bits. Therefore, the only way to guarantee error-free transport of variable rate program content is to use CBR service, or if VBR-rt service is chosen, set the Sustained Cell Rate (SCR) of the transmission channel to match the payload bitrate. However, bear in mind that CBR traffic gets a higher priority than lower class variable bitrate traffic when it comes to restoring the network from a path outage. Another undesirable characteristic, especially for live traffic where the content takes the form of an interactive interview, is the additional delay experienced by variable bitrate traffic. THE MIGRATION FROM ANALOG TO DIGITAL CONTENT TRANSPORT Consider the traditional analog world in which program content is backhauled with analog telecom facilities and 34-MHz full- or half- transponder satellite transmission facilities, then delivered to radio and television audiences over amplitude modulation (AM), frequency modulation (FM), TV, and cable transmission systems. It's been around since the beginning and works well, one program per channel. On the other hand, newer digital transmission systems such as Direct Broadcast Satellite (DBS), Digital TV (DTV), digital radio, and cable services use the same radio frequency spectrum structure, but the transmitting and receiving equipment is digital instead of analog. The DBS architecture permits 32 carriers or transponders in each satellite orbital slot. Each transponder can carry 6 to 10 standard definition programs allocated into timeslots or virtual channels in a 30Mbs digital bit stream occupying approximately 30MHz RF chan- nel bandwidth. Similarly, 6 standard definition programs (maybe more), or 2 high-definition programs can be fitted into virtual chan- nels created from a 19.4Mbs digital bit stream occupying 6MHz RF PRACTICAL IP AND TELECOM FOR BROADCAST ENGINEERING AND OPERATIONS channel bandwidth, within the Federal Communications Commis- sion's l