Patent ID: 7287065

Claim:
A data distribution system comprising: a data distribution server for supplying data to a user side; at least one access server provided on the user side and transferring intended data to each user; and a network cache apparatus provided in a network wherein said data is distributed between said data distribution server and said access server, said network cache apparatus having a cache function unit for temporarily storing said data from said data distribution server and an exchange function unit for routing the stored data to said access server corresponding to a destination user, said cache function unit storing said data for a valid term based on a distribution valid term transferred from said distribution server, simultaneously with said data, the stored data being transmitted to said access server after confirming that a reception buffer of said access server is not in a congestion state, wherein both said data distribution server and network cache apparatus and both said network cache apparatus and access server are connected via an optical cross-connect equipment forming said exchange function unit of the network cache apparatus and said data is distributed by wavelength multiplex transmission, said data distribution server is provided with a first congestion monitor indicating unit for transmitting a first inquiry request command to the network cache apparatus and inquiring about the congestion state thereof when said data must be transmitted to said network cache apparatus, said network cache apparatus is provided with a first congestion monitor responding unit for receiving said first inquiry request command, inquiring about the congestion state thereof, and returning the result to said congestion monitor indicating unit as a first inquiry response, and said data distribution server transmits said data when said first inquiry response indicates “no congestion”.