Because of its Huawei OTN network based on wavelength division, is asynchronous, don't need to be synchronized between equipment and devices, of course, this is right, but that is not absolute.Now many otns equipment in addition to wavelength division and optical cross, cross, and electricity to put it bluntly, is in fact more than WDM so simple, is actually the Huawei MSTP (SDH) + IP + DXC + ODXC + WDM, the MSTP (SDH) has become a a piece of the board, its OTN equipment and MSTP is need to be synchronized, if with based on MSTP (SDH) this kind of boards, just need to configure the clock, and configure the clock way transmission between the site (wavelength can be in business with transfer conditions, can also be in OTN management wavelength OSC. For for wavelength conversion interface card only, do not need to configure the clock.