Jini?s discovery protocols allow people to access requested services spontaneously in their own federations. However, to access services in remote federations, people have to know where the remote lookup services of them are located. This prerequisite is owing to Jini?s discovery protocols relying on multicasting support, which becomes an issue when people want to access services across non-multicastable federations. Jini system, moreover, cannot handle the mobility. When mobile clients join into a new federation, they have to relocate services, which were installed in the initiating federations. All these problems are consequent on lack of communication between federations in the current Jini system.

In this paper, we propose two new schemes to extend the Jini lookup service: one is called Inter-Federation Communication; and the other is called Proxy-Object Forwarding. In the first scheme, we construct an extended lookup service in charge of the inter-federation service lookup. In the second one, we predict the federations that mobile clients will move to, and forward the requested proxy-objects to the predicted federations. With the effort of this paper, the performance of the Jini system is enhanced. Our experiments show the significant improvement in response time with Inter-Federation Communication and Proxy-Object Forwarding.