Abstract: There are provided a system and method of assessing latency of forwarding data packets in virtual environment. The method comprises: generating packet signatures SGD and SGA respectively for departing and arriving data packets; maintaining a first data structure comprising records related to departing packets associated with a first virtual function (VF), each record informative of SGD and registered departure time TD of a given departing packet; responsive to registering arriving time TA of a given monitored arriving packet SGA associated with a second VF, searching the first data structure for a record matching a matching condition SGD=SGA; modifying the matching record to become informative of latency ?T=TA?TD and adding the modified record to a second data structure; and using data in the second data structure for assessing latency of forwarding packets from the ingress virtual port to the egress virtual port.

Abstract: Disclosed is an optical coupler device, especially for monitoring purposes in an optical point-to-point transmission link, which includes a first, a second and a third optical port and is configured to transmit a first optical signal received at the first optical port to the second optical port and to transmit a second optical signal received at the second optical port to the first and third optical port according to a monitoring split ratio with respect to the optical power of the second optical signal, the first and second optical signal having a wavelength lying in a first optical band. The device is further configured to transmit a third and a fourth optical signal received at the third and the second optical port to the respective other optical port, the third and fourth optical signal having a wavelength lying in a second optical band. The device is controllable with respect to the monitoring split ratio and includes a control means adapted to receive a control signal.

Abstract: There are provided a clock node, a controller, a method of operating the clock node and a method of operating the controller in a time distribution network (TDN) comprising the controller being in data communication with the clock nodes via a control path. The method of operating the clock node comprises: sending, from the clock node via the control path to the controller, a first timestamp-related data; receiving, by the clock node via the control path from the controller, clock-recovery control data generated by the controller using the first timestamp-related data received from the clock node; processing the received clock-recovery control data to extract data usable for phase and frequency recovery; and using the extracted data to steer frequency and phase characterizing the clock node.

Abstract: The invention relates to a method for establishing a communication channel, preferably an embedded control channel, between a central network node and at least one network unit to be integrated in a communication network including the central network node and an arbitrary but limited number of network units. The central network node is adapted to create and output a wavelength-division multiplex (WDM) downstream signal including downstream channel signals to be transmitted to the network units and to receive a WDM upstream signal including upstream channel signals created by the network units.

Abstract: The invention relates to a method for creating a control channel in an optical transmission signal, wherein the optical transmission signal (SDS,i, SUS,i) includes an optical carrier frequency component, a higher frequency modulation component carrying user information to be transported from a first end to a second end of an optical transmission link and a lower frequency modulation component carrying control information, the higher frequency modulation component realizing a user channel and the lower frequency modulation component realizing the control channel, and wherein the lower frequency modulation component is created by amplitude modulation. According to the invention, the lower frequency modulation component includes a binary digital pilot tone signal component which corresponds to a pilot tone signal having a predetermined pilot tone frequency (fi).

Abstract: The invention relates to an optical WDM transmission network including at least one optical line terminal, a remote node and a plurality of optical network units. The at least one optical line terminal is connected to the optical remote node via an optical WDM path. Each optical network unit is connected to the optical remote node via an optical distribution path.

Abstract: A transmitter with at least one optical modulator adapted to modulate the optical signal output by a laser source to generate a modulated optical signal, wherein the optical signal output by the laser source is tapped and supplied to a monitoring circuit comprising an optical front end configured to select signal components of the tapped modulated optical signal and to convert the selected signal components of the tapped modulated optical signal into analog signals, and comprising at least one analog-to-digital converter, ADC, adapted to perform equivalent-time sampling of the analog signals to provide digital signals processed by a processing unit to monitor signal quality of the modulated optical signal.

Abstract: A time aware device for a packet switched network comprising at least one time tag processing unit adapted to process time tag data of a predetermined time tag data field (TTDF) provided within a header of a tagged data packet (TDP) transported in said packet switched network to provide time related information reflecting a delay undergone by said tagged data packet (TDP) during its transport in said packet switched network.

Abstract: An asymmetrical network switch adapted to auto-discover and advertise into a traffic engineering, TE, domain a switch detailed connectivity matrix, SDCM, containing for each allowed switching combination of interfaces of said asymmetrical network switch at least one switch detailed connectivity matrix entry, SDCME, wherein each said SDCME represents an internal to said asymmetrical network switch potential connection interconnecting the interfaces of said interface switching combination, wherein a SDCME advertisement includes a switch detailed connectivity matrix entry cost vector, SDCME CV, which comprises a set of attributes describing cost penalties in terms of various service characteristics that a network service incurs if it selects a path or a tree traversing the asymmetrical switch in accordance with the SDCME.

Abstract: A method and an apparatus for providing a flexible secondary data path control, said method comprising the steps of: detecting (S1) a primary data path failure of a primary data path between a customer premise site (3) and a central office site (4); initiating (S2) a corresponding secondary data path if a primary data path failure of said primary data path has been detected; initiating (S3) a measurement of data path characteristics of said initiated secondary path or utilizing constantly monitored data path characteristics of paths for an available secondary data path; and determining (S4) services to be provided via said secondary data path depending on the measured data path characteristics of said secondary data path.

Abstract: A Generalized-Multi-Protocol Label Switching controlled network is described, as is a method for managing services in the network under conditions of disrupted control plane connectivity. Nodes of the network use a Resource Reservation Protocol with Traffic Engineering extension, RSVP-TE, to allocate and provision resources of the network. Each of the nodes is adapted to evaluate local RSVP Path or Resv state data after having sent at least one signaling message to a receiving neighboring node without receipt of an acknowledgement message from said receiving node within a configurable time to determine an IP address of a node being located after the non-responsive receiving node along a service path of a service in a downstream or upstream direction. Each node is adapted to send the signaling message to the determined IP address of the next node located behind the non-responsive receiving node along the service path.

Abstract: A method for tuning a tunable optical transmitter to a target wavelength includes applying at least one tuning signal to the tunable optical transmitter to control the tunable optical transmitter to create an optical calibration signal according to nominal tuning information for the tunable optical transmitter. The optical calibration signal has a wavelength lying within a secure wavelength range, and the nominal tuning information is based on a nominal wavelength dependency for the tunable optical transmitter. The method also includes measuring a deviation between an actual wavelength dependency of the tunable optical transmitter and the nominal wavelength dependency, and determining calibration information based on that deviation. The calibration information is applied to determine a corrected nominal wavelength dependency from which target tuning information is determined. The tunable optical transmitter is controlled to create an optical channel signal according to the target tuning information.

Abstract: Disclosed is a method for transmitting a low-frequency signal over a data transmission link using a digital high bit-rate signal including the steps of creating a modulated digital high bit-rate signal the average power of which varies according to the low-frequency signal, supplying the modulated digital high bit-rate signal to a first end of the data transmission link, receiving the modulated digital high bit-rate signal at a second end of the data transmission link or at an intermediate node of the data transmission link, and detecting the low-frequency signal by low-pass filtering the received modulated digital high bit-rate signal. According to the invention, the variation of the average power of the modulated digital high bit-rate signal is effected by a variation of the density of “high” bits according to the low-frequency signal.

Abstract: A method for complementing dynamic resource-level path computation with a resource grouping constraint in a network comprising the steps of deriving a resource group function, RGF, from relationships amongst network resources within at least one network element forming at least one network resource group, NRG, and performing the resource-level path computation accounting for the derived resource group function, RGF.

Abstract: An apparatus comprising high speed ports connected via an integrated high speed serial switch fabric and serializer/deserializer circuits to an internal processing logic, wherein the high speed serial switch fabric is adapted to switch a serial reception signal received by a high speed port to at least one of at least one other high speed port of the apparatus and to the serializer/deserializer circuit of the receiving high speed port.

Abstract: A network comprising a latency monitoring point adapted to calculate a forward latency of a path between a master node and a slave node on the basis of time stamps which are exchanged periodically between said master node and said slave node by a time alignment protocol used in said network.

Abstract: A Raman amplifier comprising a gain control unit adapted to control a pump power of an optical pump signal in response to at least one monitored optical feedback signal reflected back from a transmission line fiber connected to said pumped Raman amplifier.

Abstract: A first and second head-end terminal and at least one optical add/drop filter device are connected to form a transmission path. Each head-end terminal is connected through an optical fiber to a western or eastern WDM port of an adjacent optical add/drop filter device, and each optical add/drop filter device is connected, at an eastern or western WDM port, to a western or eastern WDM port of an adjacent optical add/drop filter device. At least one tail-end terminal is connected to each optical add/drop filter device, wherein a first and second channel port of the respective add/drop tail-end terminal is connected to a dedicated first and second channel port of the optical add/drop filter device through a respective optical fiber. The head-end terminals, the optical add/drop filter devices, and the tail-end terminals are adapted to establish bidirectional communication between each tail-end terminal and the first and second head-end terminal.

Abstract: An optical WDM transmission system including a plurality of first optical transceivers at a first end of an optical WDM transmission link, each including a tunable optical transmitter being adapted to create a first digital optical channel signal within the bandwidths of a set of first optical channels of the system according to tuning control information. The first channels are multiplexed in to a first WDM signal and supplied at the first end of the WDM link. Second optical transceivers at a second end link each include a transmitter adapted to create a second digital optical channel signal within a channel bandwidth of a second set of optical channels of the system. The second channels are multiplexed into a second WDM signal for transmission to the first transceivers, and demultiplexing there.

Abstract: The length of the optical fiber section under tension expands by a certain amount that is proportional to the level of tension applied to it. Monitoring the variations in the phase of the arriving signal allows to discover a fiber that is subject to a certain level of mechanical tension. With the method and apparatus according to the present invention it is possible to protect optical communication channels against failures in an optical transmission fiber that are caused by any kind of mechanical disturbances.