MIME-Version: 1.0 Server: CERN/3.0 Date: Monday, 06-Jan-97 21:59:37 GMT Content-Type: text/html Content-Length: 1659 Last-Modified: Monday, 09-Dec-96 22:00:09 GMT
The growth of Internet makes it necessary to find a solution to increasing accessing latency. Traditional caching mechanism only made copies in the local machine. However, as we consider the hierarchical topology of the network and notice that the local subnet is always much faster than the internet links, we add a new cache level between local disk and the large-scale network, making copies and storing them in a nearby subnet. Dynamic file replication does this work well. We make router the main controller for our system. A router gathers file request information while it passes the requests to the remote server and makes a replica at its local subnet when the request frequency for such file at this router exceeds a threshold. Therefore the following requests will get faster response for they can reach the replica with a shorter path. On the other hand the server load will be relieved a great deal because the reduce of data request reaching it. We made a simulator to evaluate the performance of this strategy. The simulator assumes easy model for the network and make random requests to randomly distributed files. The result shows that our system performs better than the system without replication mechanism up to the factor of 4.