http://www.rfc-editor.org/rfc/rfc7583.txt
RFC 7583: DNSSEC Key Rollover Timing Considerations, S. Morris, J. Ihren, J. Dickinson, W. Mekking2015-10-01T23:00:00-00:00This document describes the issues surrounding the timing of events in the rolling of a key in a DNSSEC-secured zone. It presents timelines for the key rollover and explicitly identifies the relationships between the various parameters affecting the process.