In server load balancing where replicated servers are dispersed geographically and accesses from clients are distributed to replicated servers, a way of distributing the accesses from clients to an adequate server plays an important role from the viewpoint of load balancing. In the paper, we propose a new network paradigm for server load balancing using active anycast. In active anycast, an end user only sends its request to group of servers using an anycast address. When this request arrives at an active router, it selects an adequate server from the viewpoint of load balancing and changes the anycast address of a packet to the unicast address of the selected server. The decision which server is the best one from the viewpoint of server load balancing is made by an active router rather than an end user, so active anycast is a network-initiated method. Simulation results show that active anycast can accomplish efficient server load balancing, even when a small part of routers are equipped with active network technology.

The next-generation IP-based mobile network must accommodate various kinds of wireless access technologies, including W-CDMA. Although the soft handover technique should be supported if W-CDMA is used, redundant paths will be created by the soft handover scheme employed by the 3rd generation mobile communication system. This paper proposes the Network Distributed Soft Handover (NDSHO) method, which achieves soft handover control in an IP network but without any redundant paths. NDSHO continuously optimizes all routing paths by relocating the data copy point dynamically during communication according to the movement of the mobile terminal. To achieve the proposed method, this paper introduces a copy point seamless relocation method and an optimal point selection method which takes advantage of OSPF. Furthermore, we show quantitatively that NDSHO makes more efficient use of system resources than the 3rd generation system.