Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Ab

Marconi Communications Gmbh

Andrea Corti

Raoul Fiorone

Riccardo Martinotti

Sergio Lanzone

Luca Palmieri

Andrea Galtarossa

Annamaria Fulignoli

Daniele Ceccarelli

Giuseppe Lorenzetto

Marco Santagiustina

A method of provisioning a control plane in a multi-technology network in response to a first connection request received from a client. The method comprises receiving the first connection request at a control plane dispatcher; analysing said first connection request and selecting a control plane based on results of the analysis and characteristics of control planes at the disposal of the dispatcher in the multi-technology network. The control plane dispatcher selects on a per connection request basis what is the best technology for that request and its requirements, taking also into account the status of the network resources.

Method and a device for provisioning control plane in multi-technology network

For protecting traffic on paths extending from a source client entity (CE) to a destination client entity (CE) via an optical transport network and attachment circuits at ingress (A,B) and egress (C,D) nodes, there are multiple paths within the OTN network, and the attachment circuits are dual homed. By sending () an indication of operational status of the dual homed attachment circuits within overhead associated with the traffic and sent with the traffic through the network, a selection can be made () of which of the provided paths and attachment circuits to use for the traffic, based on the indicated operational status, and on OTN fault detection, to protect against a fault in the attachment circuit or in the OTN network. Thus protection can extend across the edge nodes without the complexity and delays involved in interworking of separate protection schemes and without a control plane.

Protection for optical transport network with dual homed attachment circuits

For protecting traffic from a source client entity (CE) to a destination client entity (CE) via an optical transport network and attachment circuits at ingress (A,B) and egress (C,D) nodes, there are multiple paths within the OTN, and the attachment circuits are dual homed. By sending () an indication of operational status of the dual homed attachment circuits within overhead associated with the traffic and sent with the traffic through the network, a selection can be made () of which of the provided paths and attachment circuits to use for the traffic, based on the indicated operational status, and on OTN fault detection, to protect against a fault. Thus protection can extend across the edge nodes without interworking of separate protection schemes and without a control plane. Traffic flows can be multiplexed at the ingress, with the indication in the overhead having separate indications for each of the traffic flows.

Protection for optical transport network using operational status of dual homed attachment circuits

The invention relates to a method of fault monitoring in a fault monitoring entity of a network node of a network having at least a first connection-oriented network layer, having first protection measures associated therewith, and a second connection-oriented network layer, having second protection measures associated therewith. In a first step the service condition status of the first network layer is monitored using the first protection measures. In a second step the second network layer protection measures are determined for onward transmission within the second network layer depending on the service condition status of the first network layer. Since the network node is aware of the monitored status condition of both the first and second layers the protection mechanisms for the first network layer and the second network layer can be co-ordinated and the second network layer protection measure for onward transmission may be determined for optimum network fault protection operation.

Fault monitoring in connection-oriented networks

Method of re-routing traffic in a communications network () in the event of a fault () on a path across the network, the method comprising, determining whether a first node (), located between the fault and a network ingress node (), is capable of switching traffic to an alternative path which avoids the fault, and if the first node is determined to be not so capable, then determining whether a second node (), located upstream of the first node, is capable of switching traffic to an alternative path which avoids the fault.

Re-routing traffic in a communications network

A connection-oriented network () has a plurality of connections terminated at a first node (N). A recovery group (A) is configured at the first node (N) comprising at least two of the plurality of connections (LSP-, LSP-, LSP-, LSP-). Fault detection is performed over each of the connections in the recovery group (A) and the node determines if at least one recovery group fault condition is met, based on the results of the fault detections performed over the connections in the recovery-group (A). When the at least one recovery group fault condition is met, the node causes traffic on the plurality of connections in the recovery group (A) to be transferred to backup paths. When the at least one recovery group fault condition is not met, and a fault has been detected on a connection in the recovery group (A), the node causes traffic to be transferred from that connection to a backup path.

Recovery of traffic in a connection-oriented network

The invention relates in general to a communications network, and more particularly, to methods and apparatus for protecting such a network. The methods and apparatus disclose the providision path protection in a communications network () having a plurality of nodes including at least one access node (). A connection-oriented worker path () is set up between a first distribution node () and the at least one access node. A connection-oriented protection path () is also set up between a second distribution node and the at least one access node. A connection-oriented interface path () is also set up between the first and second distribution nodes. Traffic from an upstream node () is switched to the interface path () at one of the distribution nodes (). Traffic may be switched to the protection path () in response to detecting a fault () in the worker path.

Methods and apparatus for protecting a communications network

A connection oriented communications network has a plurality of nodes including a plurality of edge nodes. The network is arranged to define a primary tunnel connecting a primary one of the edge nodes to another edge node and a secondary tunnel connecting a secondary one of the edge nodes to another edge node. The network is arranged to enable switching of traffic from the primary tunnel to the secondary tunnel in the event of detection of a failure in the primary tunnel.

Resiliency schemes in communications networks

A method and a transport scheme for packets of traffic over a logical link made up of the aggregation of several physical links () connecting a transmitting side to a receiving side in which flows of incoming packets are sent to a scheduler/shaper () which selects therefrom packets for creating a global flow of packets falling within the bandwidth offered by the logical link on the basis of the bandwidth capability offered by the logical link. A distributor () distributes the global flow over the plurality of physical links () making up the logical link, oversees the physical links and sends to the scheduler/shaper signalling of a bandwidth decrease caused by failures of one or more physical links. The scheduler/shaper () is arranged to allow automatically for the logical link bandwidth variations while selecting the packets from the various incoming queues depending on the associated service class so as to cause the global flow to fall within the aggregated logical link bandwidth. This involves more queuing of packets and their possible drop according to the queue management criteria implemented, in the queues associated with the lowest service class.

Method and device for transmitting packets in a telecommunications network

Network interconnection apparatus comprising a platform with interface ports for network interconnection and comprising in turn a first series and a second series of interface port cards and an interconnection unit for commanded interconnection at least between the cards of the first and second series and between cards of the first series. The cards of the first series have their own associated MAC address tables for addressing traffic between ports through the interconnection unit. Each entry of the table has an age field defining in time the age of the entry. The content of the age field is periodically verified and if it reaches a preset maximum figure the entry is updated on the basis of the content of the age field by a corresponding entry in the table of another card of the first series and associated therewith by the information in the entry to be updated. If the content of the age field of the corresponding entry is also a maximum figure, both the entries can be deleted.

Optimized synchronization of MAC address tables in network interconnection apparatuses

An apparatus and a method are described in which a flow of packets is distributed in several separate flows over several links () forming a logically aggregated link (). The flow outgoing from each physical link is sent to its own policer () which applies to said flow a traffic policing algorithm with the policers being interconnected to exchange algorithm control parameter modification information to fit them in among the various policers while allowing for the control parameters of the others so that a distributed policer () is realized.

Traffic policing

An apparatus for compensation or emulation of polarization mode dispersion (PMD) effects occurring in an optical signal traveling over an optical fiber based link comprises controllable birefringence sections and devices for polarization conversion. Each section comprises birefringence optical members or parts thereof, and each section is followed or preceded by one of the controllable devices for polarization conversion. The birefringence sections are at least three in number, and at least one of these has a propagation delay different from that of the other sections. The apparatus comprises a detection device for PMD output and control of the controllable devices for feedback adjustment.

Optical communication system and apparatus for compensation or emulation of PMD effects

A method of detecting polarization mode dispersion (PMD) indicative parameters of an optical fiber link comprising at least one transmission channel in which is transmitted a first wideband optical signal with a bandwidth divided into sub-bands. For each sub-band is produced a second reference optical signal with which to find a third optical signal by superposition. For each of the third signals are calculated first parameters considered indicative of the PMD thereof, and with the first parameters of all the sub-bands are calculated second parameters considered indicative of the PMD of the first wideband signal. The method can be used as part of a PMD compensation method for a transmission system employing the parameters calculated for feedback piloting of a PMD compensator. A detection apparatus comprises a generator for generation of the second reference optical signals, an optical mixer for producing superimposition of the first and second signals, one or more photodetectors for finding the electrical beat signal or the first and second signals, a calculation device for calculating the first parameters, and a processor for processing all the first parameters to find therefrom the second parameters which will then be furthered processed. The detection apparatus can be part of a compensation apparatus comprising the compensator and a calculation stage for calculating the compensation and piloting the compensator. The entirety can be part of an optical fiber communication system.

Method and apparatus for detection and compensation of PMD parameters in signals transmitted over optical fiber links and system of communication therewith

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Varazze, Italy

Andrea Corti