In one example, a first Provider Edge (PE) node is configured to communicate with a second PE node through a packet-switched network and with a third PE node through the packet-switched network. The first PE node communicates with a fourth PE node via the second PE node. The fourth PE node is configured to communicate with the second PE node over a working path through a time-division multiplexing transport network. The first PE node exchanges, with the fourth PE node, protection information. Based on exchanging the protection information, the first PE node communicates with the fourth PE node via the third PE node. The fourth PE node is further configured to communicate with the third PE node over a protection path through the time-division multiplexing transport network.

In an embodiment, a data collection method includes: collecting, by a data collection device, performance indicator data of a target device based on a collection periodicity; detecting change amplitude of the collected performance indicator data that is in a change detection window, where the change detection window includes multiple collection periodicities; and when it is detected that change amplitude of the performance indicator data that is in the change detection window is greater than or equal to a change detection threshold, sending the performance indicator data that is in the change detection window to a data analysis device.

Systems and methods are provided for zero-added latency communication between nodes over an optical fabric. In various embodiments, a photonic interface system is provided that comprises a plurality of optical routing elements and optical signal sources. Each node within a cluster is assigned an intra-cluster wavelength and an inter-cluster wavelength. All the nodes in a cluster are directly connected and each node in a cluster is directly connected to one node in each of the plurality of clusters. When an optical signal from a different cluster is received at a node serving as the cluster interface, the photonics interface system allows all wavelength signals other than the node's assigned wavelength to pass through and couple those signals to an intra-cluster transmission signal. Zero latency is added in rerouting the data through an intermediate node.

A method is presented for supporting SNCP over a packet network connecting to two SDH sub-networks and transporting one or more SDH paths that are SNCP-protected in both SDH sub-networks. The packet network connects to each of two sub-network interconnection points by a working path and a protection path. The packet sub-network may provide the same type of path protection as an SDH sub-network using SNCP, while avoiding bandwidth duplication.

The present invention includes novel techniques, apparatus, and systems for optical WDM communications. Tunable lasers are employed to generate respective subcarrier frequencies which represent subchannels of an ITU channel to which client signals can be mapped. In one embodiment, subchannels are polarization interleaved to reduce crosstalk. In another embodiment, polarization multiplexing is used to increase the spectral density. Client circuits can be divided and combined with one another before being mapped, independent of one another, to individual subchannels within and across ITU channels. A crosspoint switch can be used to control the client to subchannel mapping, thereby enabling subchannel protection switching and hitless wavelength switching. Network architectures and subchannel transponders, muxponders and crossponders are disclosed, and techniques are employed (at the subchannel level/layer), to facilitate the desired optical routing, switching, concatenation and protection of the client circuits mapped to these subchannels across the nodes of a WDM network.

A method of obtaining a measure of asymmetry between optical fibers of a forward and reverse paths is provided in order to synchronize clocks of optical nodes connected by asymmetrical optical fiber paths. The method includes receiving, at first and second arrival times, from a first optical network device, a first optical signal transmitted on a first optical fiber and a second optical signal transmitted on a second optical fiber, calculating a first time difference between the second arrival time and the first arrival time. The method includes determining a measure of asymmetry between the first optical fiber and the second optical fiber based on the first time difference and a second time difference between a first time of transmission by the first optical network device of the first optical signal and a second time of transmission by the first optical network device of the second optical signal.

Systems and methods for coordinating an optical layer and a packet layer in a network, include a Software Defined Networking (SDN) Internet Protocol (IP) application configured to implement a closed loop for analytics, recommendations, provisioning, and monitoring, of a plurality of routers in the packet layer; and a variable capacity application configured to determine optical path viability, compute excess optical margin, and recommend and cause capacity upgrades and downgrades, by communicating with a plurality of network elements in the optical layer, wherein the SDN IP application and the variable capacity application coordinate activity therebetween based on conditions in the network. The activity is coordinated based on underlying capacity changes in the optical layer and workload changes in the packet layer.

Disclosed are a transmitting method, a receiving method, a transmitting device and a receiving device for interface data. The transmitting method includes: interface data is obtained by the transmitting device via a first USB interface. The interface data is processed to obtain UDP packet by the transmitting device. The UDP packet is transmitted, by the transmitting device, to a first communication module. The UDP packet is transmitted to the receiving device or switch. By adopting the disclosure, ultra-low latency transmission of USB interface data between devices in long-distance transmission can be achieved.

A method includes determining a first power level by performing a first series of measurements based on a first series of burst transmissions from an optical transmitter of an optical network unit (ONU) in an optical network. Bursts in the first series of burst transmissions include a first modified preamble. A second power level is determined by performing a second series of measurements based on a second series of optical burst transmissions. Bursts in the second series of burst transmissions include a second modified preamble. A first power level (Po) and a second power level (P.sub.1) are determined based on the first power level and the second power level and one or more additional parameters associated with transmissions from the optical transmitter are determined based on P.sub.0 and P.sub.1. Based on the additional parameters, it is determined whether the optical transmitter complies with specifications of the optical network.

A network system for a data center is described in which a switch fabric may provide full mesh interconnectivity such that any servers may communicate packet data to any other of the servers using any of a number of parallel data paths. Moreover, according to the techniques described herein, edge-positioned access nodes, optical permutation devices and core switches of the switch fabric may be configured and arranged in a way such that the parallel data paths provide single L2/L3 hop, full mesh interconnections between any pairwise combination of the access nodes, even in massive data centers having tens of thousands of servers. The plurality of optical permutation devices permute communications across the optical ports based on wavelength so as to provide, in some cases, full-mesh optical connectivity between edge-facing ports and core-facing ports.