Techniques and solutions are described for providing high-availability computing resources to service client requests. Groups of computing nodes are organized into loops, a given loop being configured to execute a particular subset of tasks, such as tasks with a hash value in a particular ranged serviced by a loop. Computing nodes within a loop can evaluate a task request to determine whether the task request conflicts with another task currently assigned to a node. If a computing node which sent out a task request determines that no conflict was identified, it can execute the task request. Communications within a loop can occur unidirectionally, such that a node which initiated a communication will receive the communication from the last loop node. Loops can be connected to form a ribbon, the ribbon providing a namespace for task execution, where hash ranges for the namespace are uniquely assigned to loops of the ribbon.

A master unit configured to manage a plurality of remote units connected in a ring topology, the master unit comprising: a network management section configured to transmit at least one of a path-state monitoring control signal and a delay measurement control signal to the plurality of remote units in a first direction and a second direction which is a reverse direction of the first direction, and receives an acknowledgement signal in response to the at least one of a path-state monitoring control signal and a delay measurement control signal; and switching control means for transmitting a forward signal received from a base station in the first direction, and transmitting a switching control signal in the second direction when a defect is detected in any remote unit among the plurality of remote units by the network management section.

A counter-directional optical network having multiple channels includes a source module connected with at least two network nodes by a fiber ribbon including an array of optical fibers. Each channel includes at least one optical fiber. The source module includes multiple signal sources, each signal source connected with one of the channels and operable to transmit a source signal in a direction in the channel. Each network node includes a modulator for processing the source signal with a data input signal forming a message signal, a switch for selecting one of the channels to transmit the message signal and a receiver connected with one of the channels for receiving a message signal from another node. The message signal is transmitted to the receiver of a receiving node in a direction opposite to the transmission direction of the source signal via the channel connected to the receiver of the receiving node.

An optical access network includes an optical hub having at least one processor, and a plurality of optical fiber strands. Each optical fiber strand has a first strand end connected to the optical hub. The network further includes a plurality of nodes connected to at least one segment of a first fiber strand of the plurality of optical fiber strands. Each node is sequentially disposed at respective locations along the first fiber strand at different differences from the optical hub, respectively. The network further includes a plurality of end-points. Each end-point includes a receiver. Each respective receiver (i) has a different optical signal-to-noise ratio (OSNR) from the other receivers, (ii) is operably coupled with at least one node of the plurality of nodes, and (iii) is configured to receive the same optical wavelength signal from the first fiber strand as received by the other receivers.

Techniques and solutions are described for providing high-availability computing resources to service client requests. Groups of computing nodes are organized into loops, a given loop being configured to execute a particular subset of tasks, such as tasks with a hash value in a particular ranged serviced by a loop. Computing nodes within a loop can evaluate a task request to determine whether the task request conflicts with another task currently assigned to a node. If a computing node which sent out a task request determines that no conflict was identified, it can execute the task request. Communications within a loop can occur unidirectionally, such that a node which initiated a communication will receive the communication from the last loop node. Loops can be connected to form a ribbon, the ribbon providing a namespace for task execution, where hash ranges for the namespace are uniquely assigned to loops of the ribbon.

An object of the present invention is to provide an optical access network that has high reliability for supporting information communication services and efficiently responds to difficult-to-predict optical fiber demand.

An optical access network configuration according to the present invention includes an optical fiber cable 11 that is looped to connect a wiring section 25 and an exchange office 10 together (hereinafter, an upper loop), an optical fiber cable 21 that is looped and laid in each wiring section 25 (hereinafter, a lower loop), and an optical fiber switching function unit 31 installed at a connection point 30 between the upper loop 11 and the lower loop 21. The optical fiber switching function unit 31 is a wiring board or an optical switch which can be switched by connector connection. The wiring board or the optical switch may be remotely controllable.

The present invention enables shortening the time required for resuming communication in a protection method that uses a backup path in an optical communication system that includes a master station device and multiple slave station devices. The slave station devices are connected to a loop path in parallel. The communication paths between the master station device and the slave station devices include a normal path and a backup path. First and second slave station devices are slave station devices that cannot perform communication via the normal path. The magnitude relationship between backup path RTTs is opposite to the magnitude relationship between normal path RTTs. If the second normal path RTT for the second slave station device is longer than the first normal path RTT for the first slave station device, the first backup path RTT is longer than the second backup path RTT, and the second backup path RTT is shorter than the first backup path RTT. Based on this fact, the master station device limits the QuietWindow, which is used in ranging processing for measuring the backup path RTT, to a size smaller than a predetermined maximum size.

A relay method includes transmitting, by a first apparatus in a ring network, a first control frame in which information of the first apparatus is stored, through a first port different from a second port where a communication failure is detected; receiving, by a second apparatus in the ring network, the first control frame through a third port, when the communication failure does not occur at a side of a fourth port different from the third port: storing information of the second apparatus in the first control frame; and transmitting the first control frame through the fourth port; and when the communication failure occurs at the side of the fourth port, determining whether a data frame flowing into the ring network is affected by the communication failure for every VLAN (virtual local area network) based on the first control frame; and switching a communication path set in an affected VLAN.

Aspects of the present disclosure relates to an indexing terminal including a multi-fiber ruggedized de-mateable connection location, a first single-fiber ruggedized de-mateable connection location and a second single-fiber ruggedized de-mateable connection location. The multi-fiber ruggedized de-mateable connection location includes a plurality of fiber positions with one of the fiber positions optically coupled to the first single fiber ruggedized de-mateable connection location.

A system and a method for multimachine phase synchronization based on optical fiber transmission are provided. The system includes a master and a plurality of slaves, where an optical fiber transmitting interface of the master is connected to an optical fiber receiving interface of one slave, the slave connected to the master is connected in series with the other slaves in turn, the master transmits phase information of a digital reference source thereof as a system synchronous phase signal to the slave connected to the master, the slave takes the received system synchronous phase signal as a phase of the local digital reference source, and transmits the system synchronous phase signal to a slave connected to an optical fiber transmitting interface of the slave through the optical fiber transmitting interface, and when the last slave is connected to the master, the master and the slaves form a closed-loop communication test.