| 摘要 |
A scheduling system and method, which employ a token passing scheme, for scheduling transmission of multimedia information between information warehouses (IWHs) and CO clusters (CCs) interconnected by ATM switch(es). Each CO cluster employs a CC schedule processor, which has means for receiving and means for storing requests for multimedia information, means for sorting and prioritizing the requests, means for forwarding requests to appropriate IWHs, and means for accepting or rejecting tokens offered by IWHs in response to a request. The IWH employs an IWH schedule processor which includes means for receiving and means for storing requests from CO clusters, means for selecting a request and generating a token to be sent to the CO cluster originating the request, and means for storing a list of CO cluster rejecting tokens. Requests received from multiple subscribers are stored, sorted, and prioritized at CC schedule processors, which forward the requests to appropriate IWHs. The schedule processor of each IWH receives and stores requests from CO clusters, selects a request to be serviced based on a first distance function and issues a token to the CO cluster originating the selected request. The CC schedule processor of each CO cluster selects a token to be accepted based upon a second distance function, and the requested multimedia information is transmitted from the IWH issuing the token to the CO cluster. Other tokens are rejected and returned to the issuing IWH. Each IWH may maintain a list of CO cluster rejecting its issued tokens.
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