A method of managing an interface to an internal message pipe, such as an FDDI bus, comprises sending a status enquiry message to request the status of each PVC having a DLCI in a specified range, receiving a subset status message containing sequence exchange numbers corresponding to the last status...http://www.google.de/patents/US5539734?utm_source=gb-gplus-sharePatent US5539734 - Method of maintaining PVC status packetized communication system
