Abstract: Mobile IP presents an efficient solution to the wide-area host mobility problem in the Internet. Nevertheless, its home registration process introduces an overhead in the local-area mobility case. A mobile host is required to register with its possibly distant home agent, whenever it changes its point of attachment to the network. Foreign agent hierarchies have been introduced to perform regional Mobile IP registration to minimize the home registration signaling overhead. In this paper, we propose a novel configurable architecture to organize cooperating foreign agent hierarchies in the foreign domain. An attempt is made not to change the mobile host home registered care-of address as long as it is within the foreign domain. In such manner, home registration signaling overhead is minimized, and the home agent is isolated from any local-area movement by the mobile host.