Abstract: Configuring a node (410, A-I, L-O) of a synchronization network, involves determining information about synchronization sources of a plurality of synchronization trails for passing synchronization information from the synchronization source (A, L, O, PRC) to the node to provide a synchronization reference. After determining automatically (210, 230, 330, 335, 340) synchronization transmission characteristics of trails (EF, FG, GH, HM, MN, OF, FI, IH) which use packet-based communication, the trails are compared automatically (240, 370), using their source information and their synchronization transmission characteristics, for selecting which of these trails to use for providing the synchronization reference for the node (N).

Abstract: The invention relates in general to clock recovery in a communications network, and in particular to clock recovery in a packet based communications network. Methods and apparatus are disclosed for determining a client timing signal 64, 70 for at least one client device 18, 20, 22, 54, 56, 92, 94, 96 at a master device 24, 58, 98. The client timing signal is compared 126 with a reference timing signal 76 of the master device. A timing difference value 36 is then determined 128 between the client timing signal and the reference timing signal. At least one packet indicative of the timing difference value is transmitted 130 from the master device 24, 58, 98 for receipt by the at least one client device for adjusting the client timing signal at the at least one client device.

Abstract: A method and mechanism for adaptive clock recovery of a service clock of a constant bit rate (CBR) service transmitted as a stream of packets over a packet network from a sending end node to a receiving end node via at least one intermediate node. The intermediate node associates the data packets relating to the CBR service with updated timestamps generated by a second reference timing signal available in the intermediate node. When recovering the service clock in the receiving end node, an adaptive clock recovery mechanism uses the updated timestamps to derive an estimated service clock, thereby reducing the effect of network-caused packet delay variation on clock recovery.

Abstract: Operation of a synchronization network that includes a number of nodes and reference clock distribution logic includes, at each of the nodes, storing a table that represents a most recent status of the synchronization network. Reference clocks are then distributed to each node in the synchronization network. If a change in synchronization status occurs at a node in the synchronization network, this change is detected. The table at the node is updated to represent an updated status of the synchronization network. Then, a synchronization network management protocol is used to distribute the updated status to other nodes in the synchronization network. Other nodes may change their status in response to receipt of the updated information, and information about these additional updates are distributed throughout the synchronization network in a similar manner, thereby facilitating control of the synchronization network.

Abstract: The present invention relates to a method and device for determining a synchronization fault in a synchronization network, where values of a clock control parameter associated with the synchronization control in a node are compared with a predicted mask value for said clock control parameter, and a synchronization fault is determined if one or more of the measured values lies outside of the predicted mask.

Abstract: The present invention relates to a method and to an arrangement for synchronising at least one local oscillator (21) with a central time-generating unit (11). The local oscillator (21) serves a so-called element (2) included in a network (A), and the time-generating unit (11) is included in a so-called main unit (1) also included in the network (A). The frequency of the local oscillator (21) can be controlled by periodic and automatic calibration. The physical requirements within a part of the network (A) that includes the main unit (1) and all elements (2, 3, 4) concerned, said part being referred to here as a limited network (B), are so well defined that the transmission time of a time stamp from the main unit (1) to an element (2) will be known with a given degree of certainty. The inter-arrival time of the time stamps is used to calibrate the local oscillator (11) together with the known transmission time.