| 摘要 |
To minimise traffic over an expensive transmission link (6), data obtained from an information provider (1, 2) in response to a request by a user (11, 12) is semi-permanently stored in the cache memory (10) of a node (8) local to the users whence it can be supplied to another user. When a user (11) requests data, its local node (8) checks its directory to see if the data is held by itself or by another node (38, Fig. 2). Only if neither node has it, is the data obtained from an information provider (1) via the expensive line 6, the information then becoming stored in the nodes cache memory (10) as well as being supplied to the user who requested it. The directories of any other nodes are updated accordingly to inform them that fresh data is available. Transaction information for chargeable data may be exchanged between nodes and between nodes and information providers. An electronic funds transfer message may accompany the request for data. Nodes may cooperate to cache data (28, 38 in Fig. 2). Node 8 may charge users 11, 12 on behalf of information providers 1, 2, so that the users need not have an account with the information provider. <IMAGE>
|
