ABSTRACT
This case study deals with the general problem of replica placement in tree networks. Informally, there are clients issuing requests to be satisfied by servers. The clients are known (both their position in the tree and their number of requests), while the number and location of the servers are to be determined. A client is a leaf node of the tree, and its requests can be served by one or several internal nodes. Initially, there are no replicas; when a node is equipped with a replica, it can process a number of requests up to its capacity limit. Nodes equipped with a replica, also called servers, can serve only clients located in their subtree (so that the root, if equipped with a replica, can serve any client); this restriction is usually adopted to enforce the hierarchical nature of the target application platforms where a node has knowledge only of its parent and children in the tree.
