A clock determining method includes: when both a second network device and a first network device are synchronous with a reference clock, simulating, by using delay information between the second network device and the first network device and clock frequency information of the second network device, a second virtual clock synchronized with a first virtual clock, where the first virtual clock is used to simulate a clock of the first network device. A clock of the second network device can thus be simulated to perform a subsequent operation by using the simulated clock. For example, the simulated clock may be used to estimate precision time protocol (PTP) message synchronization performance of the second network device. Therefore, the PTP message synchronization performance of the second network device may be pre-determined before a global navigation satellite system (GNSS) fails, to guide network operation and maintenance activities.

In one embodiment, a primary tunnel is established from a head-end node to a destination along a path including one or more protected network elements for which a fast reroute path is available to pass traffic around the one or more network elements in the event of their failure. A first path quality measures path quality prior to failure of the one or more protected network elements. A second path quality measures path quality subsequent to failure of the one or more protected network elements, while the fast reroute path is being used to pass traffic of the primary tunnel. A determination is made whether to reestablish the primary tunnel over a new path that does not include the one or more failed protected network elements, or to continue to utilize the path with the fast reroute path, in response to a difference between the first path quality and the second path quality.

In one embodiment, a primary tunnel is established from a head-end node to a destination along a path including one or more protected network elements for which a fast reroute path is available to pass traffic around the one or more network elements in the event of their failure. A first path quality measures path quality prior to failure of the one or more protected network elements. A second path quality measures path quality subsequent to failure of the one or more protected network elements, while the fast reroute path is being used to pass traffic of the primary tunnel. A determination is made whether to reestablish the primary tunnel over a new path that does not include the one or more failed protected network elements, or to continue to utilize the path with the fast reroute path, in response to a difference between the first path quality and the second path quality.

Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.

Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.

An example system includes a server communicatively connected to a cellular base transceiver station having an RF coverage area and configured for RF communication with a first entity that is a transceiver device in the RF coverage area, wherein the server comprises a first publish-subscribe broker that is part of a publish-subscribe broker network that comprises one or more publish-subscribe brokers, wherein a second entity connected to any of the one or more publish-subscribe brokers in the publish-subscribe broker network accepts communications from the transceiver device if the second entity subscribes to data packets published by the transceiver device, and wherein the data packets published by the transceiver device are routed through the publish-subscribe broker to which the second entity is connected.

An example system includes a server communicatively connected to a cellular base transceiver station having an RF coverage area and configured for RF communication with a first entity that is a transceiver device in the RF coverage area, wherein the server comprises a first publish-subscribe broker that is part of a publish-subscribe broker network that comprises one or more publish-subscribe brokers, wherein a second entity connected to any of the one or more publish-subscribe brokers in the publish-subscribe broker network accepts communications from the transceiver device if the second entity subscribes to data packets published by the transceiver device, and wherein the data packets published by the transceiver device are routed through the publish-subscribe broker to which the second entity is connected.

A time synchronization system includes a master station (100) and slave stations (200) communicably connected to the master station (100). The master station (100) includes a contention determiner (114) and a time synchronization frame processing unit (113). The contention determiner (114) determines, based on receipt timings of a plurality of first time synchronization frames transmitted from the respective slave stations (200), whether the plurality of first time synchronization frames have a possibility of contention over relay processing. The time synchronization frame processing unit (113) discards, when the contention determiner (114) determines that the plurality of first time synchronization frames have the possibility of the contention, out of first time synchronization frames that have a possibility of mutual contention, a first time synchronization frame received later.

An interface conversion apparatus includes processing circuitry. The processing circuitry measures communication quality inside the mobile communication system. The processing circuitry refers to evaluation index information specifying, for each communication group, an allowable range of variation in the measurement result of the communication quality and a fluctuation adjustment time, and determines the communication group in which a variation in the measurement result of the communication quality obtained from history information including a measurement result falls within the allowable range for each piece of identification information included in the packet. The processing circuitry selects the communication group of the packet received from the identification information of the packet received, based on a correspondence relationship between the communication group determined and the identification information of the packet. The processing circuitry controls the packet received for each communication group, using the fluctuation adjustment time in the evaluation index information corresponding to the communication group determined.

A wireless communication device according to an embodiment includes one or more hardware processors. The one or more hardware processors: collect forwarding load information about wireless communications in a wireless multi-hop network; determine, based on the forwarding load information, a degree of forwarding priority for a packet corresponding to a forwarding determination target; perform a forwarding control such that the packet corresponding to the forwarding determination target is forwarded earlier as the degree of forwarding priority is higher; and, when the packet corresponding to the forwarding determination target is forwarded, transmit the packet corresponding to the forwarding determination target by multi-cast communications or broadcast communications.