3. BASIC GAME
The caching problem we study is to find a configuration that meets certain objectives (e.g.,minimum total cost). Figure 1 shows examples of caching among four servers. In network (a), A stores an object. Suppose B wants to access the object. If it is cheaper to access the remote replica than to cache it, B accesses the remote replica as shown in network (b). In network (c), C wants to accesses the object. If C is far from A, C caches the object in stead of accessing the object from A .It is possible that in anoptimal configuration it would be better to place replicas in A and B. Understanding the placement of replicas by selfish servers is the focus of our study.