Nokia Nokia Alcatel This document specifies Hierarchical Mobile IPv6 Regional Paging (HMIPv6RP), a small and link-layer independent extension to the Hierarchical Mobile IPv6 with regional registrations, to support power-constrained operation in the mobile nodes and to reduce routing state information in the visited domain. The extension allows a mobile node to enter a power saving idle mode during which its location is known with the coarse accuracy defined by a paging area. In the visited domain only the paging mobility anchor point (PMAP) is responsible for keeping the binding cache entries for idle mobile nodes and, it re-establishes the downlink routes on demand by means of paging. This does not require snooping of data packets but is a natural extension to network-level routing. Optionally, the mobile node and the visited domain can agree on time slot based paging used for Paging Agent Advertisements to restrict link interface power-on time in the mobile node.