A protection switching method, including sending, by a first end node, a first protection switching request message to an intermediate node in response to a fault occurring on a working trail between the first end node and a second end node, wherein a protection trail of the working trail comprises the first end node, the second end node, and at least one intermediate node, receiving, by the first end node, a second protection switching request message from the intermediate node, and switching service data to the protection trail for transmission in response to receiving the second protection switching request message, where one overhead frame of each of the first and second protection switching request messages has at least two overhead information groups, and each of the at least two overhead information groups comprises a request type field, a request signal identifier field, and a bridge flag field.

Systems and methods for time slot allocation of time slots for bundled links in a shared mesh GMPLS for protect paths with different of COS may include time slot allocation divided into multiple phases with each phase having some qualification criterion to go to next phase or exit if the criterion is not met. For example, allocation of time slots for a circuit may include three phasescomponent selection phase, a connection admission phase, and an optimization phase.

A permutated ring network includes a plurality of bi-directional source-synchronous ring networks, each having a plurality of data transport stations, and a plurality of communication nodes. Each of the communication nodes is coupled to one of the data transport stations in each of the plurality of bi-directional source-synchronous ring networks.

A protection path determination method and apparatus based on an elastic optical network are provided. The method includes: searching a virtual working topology for a virtual working link satisfying a condition on receipt of a routing request of a target service; updating a residual bandwidth of the virtual working link if the virtual working link is found; otherwise, creating a working link for the target service and creating a virtual working link in the virtual working topology; searching a virtual protection topology for a virtual protection link satisfying a condition according to a shared path protection mechanism; updating a residual bandwidth of the virtual protection link if the virtual protection link is found; otherwise, creating a protection link for the target service according to the shared path protection mechanism and creating a virtual protection link in the virtual protection topology.

An optical network system includes a master node and a plurality of optical switch nodes, allowing the number of nodes without depending on the number of wavelengths. The master node is configured to: divide a wavelength path having an arbitrary wavelength into time slots each having a predetermined time period; and allocate the time slots to each of the optical switch nodes. Each of the optical switch nodes is configured to: synchronize the time slots based on information delivered from the master node; and thereby transmit or receive a data or performs route switching.

There is provided a communication method used in a communication system in which a plurality of communication apparatuses is connected by an optical ring network, the communication method including: setting one of the plurality of communication apparatuses as a master communication apparatus and the other communication apparatuses as slave communication apparatuses, causing the master communication apparatus to transmit an optical signal at transmission timing determined in the master communication apparatus; causing the master communication apparatus to transmit an assignment signal for assigning, to the slave communication apparatuses, transmission timing at which an optical signal on at least one wavelength is time-division multiplexed and transmitted; and causing the slave communication apparatuses to transmit an optical signal to the optical ring network based on transmission timing assigned by the assignment signal received from the master communication apparatus. As a result, the number of wavelengths needed for communication is reduced, and even when communication paths increases due to an increase in the number of optical transmission apparatuses, there is no need to increase the number of wavelengths, thereby solving the problem in economic efficiency.

Systems and methods for time slot allocation of time slots for bundled links in a shared mesh GMPLS for protect paths with different of COS may include time slot allocation divided into multiple phases with each phase having some qualification criterion to go to next phase or exit if the criterion is not met. For example, allocation of time slots for a circuit may include three phasescomponent selection phase, a connection admission phase, and an optimization phase.

A mesh network (such as a mesh Ethernet network) is subdivided into rings. For each ring, a network utilization is assessed in both the clockwise and counter-clockwise directions around the ring. A user requests a particular network service. The network rings that would be utilized by the network service are determined. A maximum utilization of all the network rings utilized by the network service in both clockwise and counter-clockwise is determined. The determined maximum utilization is used to determine the feasibility of provisioning the requested network service.

An apparatus for protection switching in an optical transport network (OTN) includes: a working path interface module configured to check, via a working path for protection switching, connectivity of a first end node and a corresponding second end node; and a protecting path interface module configured to check connectivity of the first end node and the second node via a protection path for protection switching. Upon confirming the connectivity, the working path interface module and the protection path interface module exchange bandwidth resize (BWR) coordination information with each other and simultaneously output an ODUflex bandwidth control signal based on the exchanged BWR coordination information.

A mesh network (such as a mesh Ethernet network) is subdivided into rings. For each ring, a network utilization is assessed in both the clockwise and counter-clockwise directions around the ring. A user requests a particular network service. The network rings that would be utilized by the network service are determined. A maximum utilization of all the network rings utilized by the network service in both clockwise and counter-clockwise directions is determined. The determined maximum utilization is used to determine the feasibility of provisioning the requested network service.