Disclosed is a process for reducing metallic oxide or sulfide materials in a rotary kiln and a rotary kiln for reducing such materials. In one embodiment, the network data processing system includes a local server, several client data processing systems, and a bait server. When the GGSN is going to deactivate the PDP Context for having been inactive for a preestablished time, an indication of such deactivation is sent to the IMS client which maintains the characteristic IMS identity-IP address association and marks it as fictitious.