This invention relates to a protocol, an information processing system, an information processing method for use with the system, information processing apparatuses, information processing methods for use with the apparatuses, storage media, and programs for allowing two-way network status to be known....http://www.google.de/patents/US20050182850?utm_source=gb-gplus-sharePatent US20050182850 - Protocol information processing system and method information processing device and method recording medium and program
