In a computer network where each mobile host is assigned a subnetwork-independent logical identifier (L-ID), the mobile host acquires a subnetwork-dependent geographical identifier (G-ID) from an agent-existing subnetwork and sends the G-ID to the home subnetwork of the mobile host for location registration...http://www.google.com/patents/US5862345?utm_source=gb-gplus-sharePatent US5862345 - System for location multicasting and database management for mobile sessions in any computer subnetworks without using a home router of a home subnetwork
