| 摘要 |
This is a system and method for managing data transmission to the set top boxes from a central system server, such as a promotion server which distributes promotion content. A precasting technique is used for transmitting promotion content files prior to promotion activation which takes into account the device attributes of the destination end node devices. More specifically, promotion content files are associated with an expected display or activation start time at the end node devices, such as a cable set top box. A package transmission lead time is calculated which depends upon the memory capacity of a specific group of end node devices, called a "transmission group," to which the promotion file is to be sent. The package transmission lead time is then taken into account to determine exactly when to send the promotion content. The promotion content is then sent at the designated time via broadcast or multicast transmissions. Other factors that may be taken into account to determine the package transmission lead time include network latency, loading factor at the origin server, and bandwidth/data rate allocated to the broadcast, duration (repetition time). Additionally, when a promotion schedule message is used to coordinate the broadcast or multicast of the content file with the end node devices, the timing of the delivery of the schedule message can be itself determined by additional factors including an schedule transmission lead time.
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