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: An apparatus for mitigation of packet delay variation, PDV, in a packet-based network, comprising an ingress port to receive event messages, each message being timestamped with a local ingress timestamp at the instant of reception of the message using a local internal clock; an extraction unit to extract a timestamp embedded in the received message; a computation unit to calculate a time offset between the extracted embedded timestamp and the local ingress timestamp of the received event message to record the calculated time offset as a maximum observed delay, if the calculated time offset exceeds a previously recorded maximum observed delay, the computation unit adjusting an internal transmission delay time before onward transmission of the event message from an egress port depending on a time difference between recorded maximum observed delay and calculated time offset of the event message to minimize the packet delay variation, PDV, at the egress port.

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: Verification of continuity for a network service path that includes at least one network function that blocks test packets may be achieved by providing a bypass mechanism to bypass test packets around the at least one network function that blocks test packets. Verification of continuity may be done when the network service is available for active use or when it is not ready for active use. Detection of a continuity problem leads to more detailed diagnostic work.

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 traffic engineering on an optical transport network, OTN, comprising network elements implementing asymmetric OTN switches, said method comprising discovering by each network element of said network ODUk containers available on each of locally terminated traffic engineering, TE, links and identifying the switching limitations of the discovered ODUk containers with respect to how said ODUk containers are switchable onto the ODUk containers available on other locally terminated TE links; identifying by said network element groups of ODUk containers available on a given TE link exhibiting identical switching limitations; negotiating by said network element with its neighboring network elements properties of to be advertised child TE links each associated with a separate ODUk group; and advertising by said network element for each identified group of ODUk containers a separate child TE link parallel to the original parent TE link, wherein each advertised child TE link indicates the total number of av

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 method and apparatus for performing an automatic power adjustment wherein a signal power level of an optical signal transmitted by an optical transceiver via an optical span to a far-end device is adjusted automatically in response to a determined span loss of the optical span to achieve a predetermined desired receive signal power level of the optical signal at the far-end device.

Abstract: The subject matter described herein includes using a path computation element communication protocol (PCEP) as a signaling protocol during dynamic service provisioning in networks. According to one aspect of the subject matter described herein, a network uses a hard state point-to-point protocol as a signaling protocol during dynamic service provisioning in a control plane of the network. In one implementation, the point-to-point protocol is a path computation element communication protocol (PCEP).

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.

Abstract: A method for assessing the performance of packet synchronization services in a packet data transmission network. The method includes, at a packet data transmission network probing point, determining at least two synchronization quality describing or influencing parameters based on at least one of a digital timing signal (Sp) received, the recovered time information for at least one timing parameter transmitted into the packet data transmission network, and parameters having impact on the synchronization quality and describing or controlling properties of hardware components present at a receiving network node. The method also includes, at the packet data transmission network probing point, determining a value of at least one synchronization performance score based on the at least two synchronization quality describing or influencing parameters.

Abstract: The invention relates to a method of operating a first optical network element (100), particularly an optical network unit, ONU, wherein said method comprises the following steps: performing a coarse tuning process (2100) of at least one transmission wavelength which is used by said first optical network element (100) for transmitting an optical signal to a second optical network element (200), particularly an optical line terminal, OLT, and performing a fine tuning process (2200) of said at least one transmission wavelength, wherein said fine tuning process (2200) is preferably performed after said coarse tuning process (2100).