White Rabbit Absolute Calibration

White Rabbit (WR) is a widely used implementation to create high accuracy time dissemination networks. On-site network calibration can be avoided when using absolute calibrated components, which can be freely exchanged without recalibration. Absolute calibration of high accuracy time dissemination network components enables independent developers and/or vendors to exchange their calibrated components while achieving absolute sub ns timing. Absolute calibration enforces standardization. This paper presents procedures and methods for absolute calibration of time dissemination networks, in particular WR.