http://www.rfc-editor.org/rfc/rfc3992.txt
RFC 3992: Media Gateway Control Protocol (MGCP) Lockstep State Reporting Mechanism, B. Foster, F. Andreasen2005-02-01T23:00:00-00:00A Media Gateway Control Protocol (MGCP) endpoint that has encountered an adverse failure condition (such as being involved in a transient call when a Call Agent failover occurred) could be left in a lockstep state whereby events are quarantined but not notified. The MGCP package described in this document provides a mechanism for reporting these situations so that the new Call Agent can take the necessary fault recovery procedures. This memo provides information for the Internet community.