1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities@ IEC publishes International Standards@ Technical Specifications@ Technical Reports@ Publicly Available Specifications (PAS) and Guides (hereafter referred to as ??IEC Publication(s)??). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International@ governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.2) The formal decisions or agreements of IEC on technical matters express@ as nearly as possible@ an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate@ IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.4) In order to promote international uniformity@ IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication.6) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC/IEEE 61588 has been processed through subcommittee 65C: Digital communications@ of IEC technical committee 65: Industrial-process measurement and control.This standard defines a protocol enabling precise synchronization of clocks in measurement and control systems implemented with technologies such as network communication@ local computing@ and distributed objects. The protocol will be applicable to systems communicating by local area networks supporting multicast messaging including@ but not limited to@ Ethernet. The protocol will enable heterogeneous systems that include clocks of various inherent precision@ resolution@ and stability to synchronize. The protocol will support systemwide synchronization accuracy in the submicrosecond range with minimal network and local clock computing resources. The default behavior of the protocol will allow simple systems to be installed and operated without requiring the administrative attention of users.