Abstract: A method for synchronizing a plurality of clocks arranged within a plurality of nodes of a packet-switching network comprises comparing parameters that relate to the plurality of clocks in order to determine master-slave relationships between the plurality of clocks, and exchanging time-stamped messages over the packet-switching network each time between a master clock and an associated slave clock to make the associated slave clock subservient to the master clock. A node of the packet-switching network comprises a frequency source controlled by a synchronous physical layer technology. The parameters that relate to a clock of the node comprise a parameter that relates to the frequency source to determine the master slave relationships based on one property of the frequency source.

Abstract: Systems and methods are disclosed that determine whether a sender/recipient using an electronic messaging service (e.g., SMS messaging service or MMS messaging service) is located in a defined home zone. A communication network in one embodiment includes a messaging system, such as an SMSC or an MMSC, and a home zone system. If the messaging system receives an electronic message from a sender to a recipient, then the home zone system determines a location of the sender/recipient. The home zone system also determines whether the sender/recipient is located in a home zone. If the home zone system determines that the sender/recipient is located in a home zone, then the messaging system forwards the electronic message to the recipient. If the home zone system determines that the sender/recipient is not located in the home zone, then the messaging system blocks the electronic message.

Abstract: Method, in a presence and intermediation system, to transfer from one owner (15) to at least one watcher (17) at least a share of owner's presence information related to at least one owner's buddy (13, 14, 16) in order to enable said watcher (17) to replace the owner (15) toward said buddy (13, 14, 16). Presence and intermediation system comprising means to apply the said method.