Abstract: It is disclosed a method of monitoring, a Multi-Protocol Label Switching network, a tandem connection of a Label Switched Path. The tandem connection to be monitored has an input node and an output node. The method comprises the following steps: receiving a first Operation Administration Management packet at the input node; and generating a second OAM packet at the input node. According to the invention, the following steps are further performed: a tandem connection header is inserted into the first OAM packet; both the first OAM packet with the tandem connection header and the second OAM packet are sent towards the output node; and the second OAM packet is identified according to the presence or absence of said tandem connection header.

Abstract: A method for controlling data transfers through a computer system is provided. First information is transferred to a first node of the computer system regarding availability of a first data storage area within a second node of the computer system for data to be transferred through the second node. Also transferred to the first node is second information regarding availability of a second data storage area within the second node for data to be consumed within the second node. The first information and the second information are then processed to determine if data within the first node destined for the second node is to be transferred to the second node.

Abstract: A system and method for measuring convergence performance in a network are disclosed. In one embodiment, the method includes receiving a plurality of probes at a network device, temporarily storing data from at least a portion of the received probes and deleting at least a portion of the temporarily stored data at regular intervals, and receiving a packet indicating a convergence event and storing data from probes received over a predetermined period.

Abstract: An ATM switch allowing simplified OAM processing only on the line incoming side is disclosed. An incoming line circuit has a header conversion table storing information indicating whether the system is an end point of an OAM processing flow for each connection and an OAM table storing an AIS flag and an RDI flag for each connection. As for an OAM cell found by referring to these tables to be forced to go back to its own port, an switch output port number is rewritten in the OAM function section. In addition, in the case of an AIS cell, the function type is rewritten so as to become an RDI cell. In the case of an LB cell, the LB indication is rewritten so as to become a return LB cell, and switching to its own port is conducted in the ATM switch core.

Abstract: A system and method for propagating fault information in an Ethernet OAM network having multiple levels of OAM domains. An Alarm Indication and Suppression (AIS) frame is generated by a Maintenance Intermediate Point (MIP) node upon detecting a fault condition in a first OAM domain, which is transmitted to one or more Maintenance End Points (MEPs) of the first OAM domain. Upon receiving the AIS frames, the MEP nodes are operable generate another AIS frame for propagating to an adjacent higher level second OAM domain. Responsive to the AIS frame from the lower level first OAM domain, any alarms caused in the second OAM domain due to the fault condition in the first OAM domain are suppressed.

Abstract: An improved system and method for transmitting a multiplexed service stream over an error prone DVB-H channel. Media IP packets are priority labeled. For each time slice burst, the IP packets are grouped based upon the priority labels. MPE-FEC matrices are made for the different priority labels in each time slice burst. RSDT columns are computed such that the average service bit rate does not overshoot the maximum allowed service bit rate, and the protection increases with priority. The ADT and RSDT of the MPE-FEC matrices are then encapsulated into MPE-FEC sections.

Abstract: In one embodiment, data is received from a plurality of token devices and the rate of transmission is adjusted to match a lowest reception rate of the plurality of token devices using the data.

Abstract: A method and system of routing information packets through a network is presented. The method may include receiving an information packet at a node in a network, wherein the information packet contains information relating to a new metric, forming a new routing protocol based on the new metric information contained in the information packet, and implementing the new routing protocol on the node, wherein the new routing protocol computes routing information based on the new metric information.

Abstract: Various embodiments provide a way to adjust transmission rates of a medium access controller (MAC) to a physical layer (PHY) to accommodate for packet expansions due to encryption that takes place in the PHY. In at least some embodiments, a communication interface between different MACs in a system is re-purposed to allow the PHY to communicate to a system MAC to notify the system MAC to pause and then resume, at an appropriate time, its packet transmissions.

Abstract: The claimed subject matter provides systems and/or methods that uncovers detailed differences in the performance of different Internet Service Provider ISP) networks. The system can include components, devices, and/or processes that utilize a list of target Internet Service Provider (ISP) networks to create a list of Internet Protocol (IP) addresses to interrogate, distribute the list of addresses to measurement nodes and obtains in return probing results from the measurement nodes, the probing results employed thereafter to provide comparative performance metrics associated with the target Internet Service Provider (ISP) networks.

Abstract: An optical network and method for managing a service across an optical network over a dedicated circuit between first and second service termination points include generating a service performance report message (PRM) at each service termination point. Each service PRM has service-specific information related to a performance of the service as determined by the service termination point generating that service PRM. Each service PRM identifies the service to which the service-specific information in that service PRM pertains. Each service termination point transmits the service PRM generated by that service termination point across the optical network over the dedicated circuit to the other service termination point through a service management channel of an optical transport facility.

Abstract: Methods and devices are provided for encapsulating FC frames from a network device as Ethernet frames. Preferably, the FC frames represent traffic for a plurality of ports of the network device. The encapsulated Ethernet frames may be input to a conventional network interface card of a personal computer (“PC”) or laptop. Therefore, encapsulating the FC frames allows an engineer to use software installed on a conventional PC to troubleshoot problems with a network using FC protocol. According to some aspects of the invention, FC frames may be truncated to various degrees, to allow smaller data frames to be output at an appropriate rate to the analyzing personal computer, laptop, etc.

Abstract: A method of re-establishing a connection for a communication link is provided. The link has first and second portions, having the first portion in a first communication network, the second in a second communication network and an interface connecting first portion to the portion. The first communication network has a first communication protocol and a first OAM protocol to monitor integrity of the first portion. Similarly, the second communication network has a second communication protocol and a second OAM protocol. The method utilizes the second OAM protocol to detect a failure in the second portion. Upon detection of the failure, an alternate route for the second portion in the second communication network is identified, where the alternate route is able to complete the second portion of the communication link from the interface. For the communication link, at the interface the second portion is replaced with the alternate route.

Abstract: Embodiments of the present invention disclose a method of domain supervision in a label switched network, including: designating one or more OAM domains on an LSP in the label switched network, determining an ingress node and an egress node of each OAM domain, inserting in-domain OAM frames containing supervision information at the ingress node of each OAM domain, receiving and parsing the in-domain OAM frames by the egress node of each OAM domain, and managing an OAM domain according to the supervision information contained in an in-domain OAM frame of the OAM domain. Furthermore, embodiments of the present invention also disclose a method of domain protection in a label switched network through adding a detection frame, such as Connectivity Verification (CV) frame, Fast Failure Detection (FFD) frame or the like, into an in-domain OAM frame.

Abstract: In one embodiment, a flow control module aggregates indications of queuing resource utilization at devices attached to a switching fabric within a router and broadcasts that information out of band to all devices attached to the same switching fabric. When the flow control module identifies congestion at one of the attached devices according to the indications, the module may also cause a throttling of traffic sent to the congested device in addition to sending the out of band indication of the congestion to all the attached devices. Flow control modules for each of the attached devices provide local interrupts for reducing outbound traffic to a congested device according to the identification of that remote congestion.

Abstract: Systems are provided for sequencing, delivery acknowledgement, and throttling of data packets over a network layer, such as UDP and SMS. To support devices with limited battery resources, the invention incorporates asymmetric retry logic and/or acknowledgements with overlapping ranges, to minimize the transmissions required for the device. The sender of a data-bearing frame does not need to wait for a frame to be acknowledged before sending the next, such that many frames can be “in flight” at once.

Abstract: A method for detecting link failures between nodes in hybrid networks includes: establishing sub-BFD connections between nodes and edge nodes and establishing an end-to-end BFD connection. When a failure occurs in the sub-BFD connection of IP network segment, notify a peer node of the failure via the end-to-end BFD connection. When a failure occurs in the MPLS OAM mechanism of MPLS network segment, the edge node notifies the node of the failure via the sub-BFD connection. Another method includes: establishing sub-BFD connections between nodes and edge nodes. When one end of the sub-BFD connection failures, notify the IP network segment at the peer end of the failure via an extended MPLS OAM mechanism and notify the node of the failure via the sub-BFD connection of the IP network segment. An interworking between the BFD detecting mechanism and the MPLS OAM detecting mechanism in a hybrid network can be implemented.

Abstract: Disclosed is a method and apparatus for improving LAN availability and robustness employing adjacency status self-discovery on segment-to-segment communications paths. In some embodiments, the method and system may employ Logical Link Control Type 1 test frame messages between segment nodes to determine status. Adjacent node status may be determined by waiting a period of time for an acknowledgment message and marking the tested link as “down” if no response is received. Also disclosed is a method for compacting data transmitted over a network to reduce overhead.

Abstract: An ATM (asynchronous transfer mode) cell transfer apparatus includes an input interface, a switch block, and an OAM cell processing hardware block having a memory unit. The input interface receives an SDH/SONET signal on each of a plurality of first transfer paths to output an input OAM cell corresponding to the SDH/SONET signal to one of a plurality of input ports of the switch block corresponding to the first transfer path for the SDH/SONET signal to be transferred. The switch block receives the input OAM (operation and maintenance) cell from the corresponding input port as an OAM input port to output to the OAM cell processing hardware block together with a port number of the OAM input port, and receives at least one output OAM cell from the OAM cell processing hardware block to output to at least one of the plurality of output ports based on the received output OAM cell.

Abstract: Apparatus and methods of determining configurations for handling communication path management traffic are disclosed. Respective communication path management traffic handling configurations of communication system elements that terminate a communication link, which is a portion of a communication path, are determined. If the respective communication path management traffic handling configurations indicate that the communication system elements have been configured to pass communication path management traffic associated with the communication path toward endpoints of the communication path, then communication path management traffic for managing the communication path is exchanged through the communication link. Indications of a communication path management traffic handling configuration may be exchanged between the communication system elements during establishment of the communication link.

Abstract: Object-based operation and maintenance (OAM) systems and related methods and computer program products are disclosed. One exemplary system includes a computer comprising a memory. The computer is in communication with a network comprising a network-attached components operating in an OAM system. The system can also include an object-based representation of the network stored in the memory. The object-based representation comprises objects linked together in the memory to form a hierarchy. Each of the objects represent the network or the network-attached components. In addition, each of the objects stores attribute information about the network or the network-attached components with regard to the OAM system. Further, the system can include an application for interpreting and utilizing the object-based representation of the network for operating and maintaining the network and network-attached components in the OAM system.

Abstract: A loop detection system and method operable in an Ethernet network having a provider network and a customer network. In one embodiment, a provider edge (PE) entity is operable to generate a test frame with at least one of a destination address (DA) and source address (SA) that is unknown to the customer network. The test frame is broadcast to the customer network coupled to the PE entity. Upon determining that the test frame or its duplicates are received back by the PE entity within a first time period, loop location within the Network is deduced responsive to the determination.

Abstract: Data representing video content is distributed over a passive optical network (PON) on virtual channels that are assigned to television (TV) channels as subscribers request the TV channels and de-assigned from TV channels when subscribers are no longer viewing them. Associating and de-associating TV channels with virtual channels can be performed with very low latency by using a near-physical layer protocol, such as the Physical Layer Operation Administration and Maintenance (PLOAM) protocol.

Abstract: Systems, methods, and computer program products for providing a distributed hardware platform interface (HPI) architecture are disclosed. According to one aspect, the subject matter described herein includes a system for providing distributed operations, administration, and maintenance (OAM) functionality in a multi-shelf processing environment. The system includes a first shelf that includes first hardware components, a second shelf that includes second hardware components, and an OAM module for providing an OAM function. The system also includes a first hardware platform interface (HPI) daemon for communicating OAM-related information between the first hardware components and the OAM module, and a second HPI daemon for communicating OAM-related information between the second hardware components and the OAM module.

Abstract: An Ethernet switch (112) has a communications interface (122), and a controller (124). The controller is programmed to receive (202) an IP query packet generated by a receiver for collecting telemetry data between a source and the receiver in a multicast network, translate (206) the IP query packet to an Ethernet query packet, collect (208) in the Ethernet query packet telemetry data from the Ethernet switch, and submit (218) the Ethernet query packet to the next network element of the multicast network. Additional embodiment are disclosed.

Abstract: A link aggregation function and maintenance function by MPLS OAM. Identical entry information is stored in plural circuits IF which perform a LA setting. In this way, multiplexing to the same LSP is possible even with different IF. The first network IF is assumed to be OAM ACT, and the second network IF is set to OAM SBY (SBY). OAM frame insertion is performed only by an OAM ACT port. In this way, in an opposite MPLS transmission apparatus, it is possible to prevent CV frame reception above a specified number of frames. Further, a switch forwarding table is set to forward frames from the network side to the first network IF of OAM ACT. The second network IF which was set to OAM SBY does not perform fault detection by CV reception. In this way, incorrect detection of faults due to non-reception of OAM can be prevented.

Abstract: A communication apparatus is disclosed for receiving one or more frames from a network. The communication apparatus includes a first determining part configured to search a first table by using a VLAN identifier included in one of the frames, a second determining part configured to search a second table by referring to a search result of the first determining part and using an OAM identifier included in the one of the frames, a selecting part configured to determine whether the one of the frames is an OAM frame according to the search result of the second determining part, and a terminating part configured to terminate the one of the frames determined as the OAM frame by the selecting part.

Abstract: A method and system for emulating an Ethernet link over a Sonet path to provide link integrity is disclosed. The method generally includes receiving an error code at a local Ethernet port upon detection of a link failure at a remote Ethernet port. The error code is received over a Sonet path in a Sonet path overhead. If the error code is still present after a specified period of time, the local Ethernet port is disabled. Methods for providing link stability and link availability are also disclosed.

Abstract: A method of encapsulating data packets for use in a distributed computer network is disclosed. The method includes providing a data packet for transmission over the distributed computer network, the data packet selected from one of a customer data packet and an OAM data packet; and encapsulating the data packet with a medium access control outer packet. The disclosed data packet handling method includes receiving a data packet from a customer facing data port, the customer facing data port within a network node of a computer network; performing medium access control (MAC) learning for the received packet; determining whether the data port is a MAC-in-MAC port; performing a packet mapping to a destination address based on a service provider destination address; and encapsulating the received data packet with a header associated with the service provider.

Abstract: A telecommunications system. The system includes a first node. The system includes a second node. The system preferably includes at least one intermediate node in communication with the first node and the second node. The first node, second node and intermediate node defining a path. The first node repeatedly sending signaling through the intermediate node to the second node and receiving the signaling back to establish and maintain a connection between the first node, second node and intermediate node. The system includes means for dynamically placing connection points along the path through which the connection is established each time after signaling from the first node to the second node returns to the first node. A method for forming connections in a telecommunications system.

Abstract: A device and method are disclosed for correctly restoring a read clock when there are a plurality of STM data stream transmission sources. In a CES device of an ATM communication system, ATM cells from respective connections, which are to be delivered to the same outgoing line, are accumulated in a reassembly buffer memory and a PLO control unit aggregates the amount of ATM cells accumulated in the reassembly buffer memory for each connection. Subsequently, the PLO control unit calculates the frequency of a read clock based on the amount of accumulated ATM cells for each connection. A PLO restores the read clock which is applied to read data from the reassembly buffer memory for delivery to an STM network.

Abstract: A method for alert throttling in media quality monitoring, includes monitoring a plurality of active communication sessions. Each active communication session is between at least two endpoints. The method also includes detecting at least one quality-impacted communication session out of the plurality of active communication sessions. The method also includes generating a first alert for each detected quality-impacted communication session out of the plurality of active communication sessions until a first throttling number of quality-impacted communication sessions is detected out of the plurality of active communication sessions. Upon detecting the first throttling number of quality-impacted communication sessions, the method includes generating a second alert for each group of additional second number of quality-impacted communication sessions detected out of the plurality of active communication sessions.

Abstract: A method and system for aggregating data in an enterprise network are provided. In one embodiment, a method for processing data in an enterprise network includes receiving real-time network performance data associated with a network resource. A database is updated with the real-time network performance data. The database table includes historical network performance data associated with the real-time network performance data.

Abstract: Methods and systems for providing necessary and sufficient quality-of-service (QoS), in a packet-based core transport network that utilizes dynamic setting of bandwidth management pipes or thresholds to obviate link congestion are disclosed. Congestion avoidance is a necessary and sufficient requirement in order to guarantee Quality of Service (QoS) in packet-based core networks. A typical network is composed of a plurality of backbone links connecting edge nodes where backhaul links are aggregated. The backhaul links connect the backbone links to the remote sites serving the subscribers. In order to enforce bandwidth management policies, Access Controllers, which perform traffic shaping, are situated on each remote site. In the event of a violation of certain link threshold settings, dynamic adjustment of the bandwidth management policies on affected Access Controllers is enforced.

Abstract: Provided are an apparatus and method for managing quality of a multi protocol label switching (MPLS) label switched path (LSP), which has been previously established in a convergence network. The apparatus for managing quality of a LSP includes: LSP provisioning/releasing means for provisioning and releasing the LSP in a convergence network; and LSP quality management means for measuring the quality of the LSP on the basis of performance information received from the each node through which the LSP passes, wherein the LSP quality management means transmits alert information to the LSP provisioning/releasing means, when the measured quality of the LSP deviates from a predetermined performance threshold, so that the LSP is readjusted.

Abstract: In one embodiment, a tunnel mesh probe, initiated for a computer network having a tunnel mesh, may be received at a first tail-end node of a probed tunnel. In response, the first tail-end node processes the probe, and forwards the probe to another tail-end node of a non-probed tunnel selected from a plurality of tunnels of the tunnel mesh for which the first tail-end node is a head-end node. Illustratively, once the probe is received at its initiating node, and in response to determining that the initiating node is a head-end node for only probed tunnels, the tunnel mesh probe is completed, having probed all tunnels of the tunnel mesh.

Abstract: Provided is a method for measuring performance of a multi-protocol label switching label switched path (MPLS LSP), using a fast failure detection (FFD) packet among MPLS operation and management (OAM) packets recommended by International Telecommunication Union-Telecommunication standardization sector (ITU-T) Y.1711 to detect a packet error generated in the MPLS LSP and newly defining bytes not used in the FFD frame to use the bytes for parity check. An ingress node performs the steps of: calculating a parity value of an MPLS packet as byte interleaved parity (BIP)-8 before transmitting the MPLS packet; storing the calculated parity value of the MPLS packet in an MPLS OAM packet of an FFD structure; and transmitting the MPLS OAM packet whenever transmitting the MPLS packet.

Abstract: A traffic control system and method with flow control aggregation. The system includes a switching fabric and an ingress module. The switching fabric includes read counters that are associated with a plurality of queues. The read counters represent an aggregated number of cells dequeued from respective queues since a previous flow control message (FCM) was sent to the ingress module. The read counters are reset when a FCM is created. The ingress module includes write counters that are associated with the queues. The write counters are incremented each time a cell is sent to the respective queues. The write counters are decremented in accordance with the FCM when the FCM is received. Also, read counters for one or more queues are aggregated into a single FCM.

Abstract: In an IP packet communication apparatus, an operation and maintenance function capable of monitoring a transmission path is provided to a layer used to process a packet, which corresponds to an upper layer of an optical network. As one method for applying the operation and maintenance function to the packet layer, in the case of IP over PPP over WDM, an operation/maintenance frame is defined to a PPP frame so as to realize the operation/maintenance function of a PPP connection. In the case that a plurality of connections are multiplexed on the same transmission path, a maintenance frame is conducted in order to operate/manage these connections by being grouped, so that a fault occurring in the optical network is monitored. As another method for applying the operation and maintenance function to the packet layer, an operation/maintenance frame is defined to an IP packet so as to realize an operation and maintenance function of an IP flow.

Abstract: A broadband access node includes a port for connection with a Digital Subscriber Line and a processor to run code that implements a virtual maintenance end point (vMEP). The vMEP translates an IEEE 802.1ag Loopback Message (LBM) received from a device on an Ethernet access network into a legacy operations and maintenance (OAM) message that is transmitted to a residential gateway (RG) device. The legacy OAM message determines a link-level connectivity status between broadband access node and the RG device. The vMEP also transmits a reply message back to the device on an Ethernet access network in compliance with the IEEE 802.1ag specification. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: There are provided a printing apparatus which can maintain an optimal transfer rate with an external device by an optimal buffer management, and a reception buffer management method thereof. In the printing apparatus according to this invention, assume that data received in unit of packet using a wireless interface from the external device is stored in a plurality of reception buffers. A maximum receivable data amount which can be used for receiving the data from the external device is determined on the basis of the number of the confirmed empty reception buffer(s). The data transmittable amount notified of the external device is then compared with the maximum receivable data amount. When receiving a request from the external device, the printing apparatus replies to the external device to change the notified data transmittable amount, in accordance with the comparison result.

Abstract: A method and system are provided for verifying connectivity between monitoring points (MPs) within a network. The method comprises assigning, to each monitoring point, a unique MP ID and a unique sender MP ID and a unique receiver MP ID. Each sender MP ID uniquely identifying a sender MP from which a corresponding MP will receive valid monitoring messages. Each receiver MP ID uniquely identifying a receiver MP to which the corresponding MP transmits a valid monitoring message. The method further includes transmitting the monitoring messages MP ID in a unidirectional monitor cycle through the MPs, where each monitoring message includes a sender MP ID and a receiver MP ID. The method determines connectivity at each MP based on the sender and receiver MP IDs in a monitoring message received at the MP. Optionally, the method and system may report, from a monitoring point, a loss of connectivity when no valid monitoring message is received at the monitoring point for a predetermined number of monitor intervals.

Abstract: Described are a system and method for managing a service across an optical network over a dedicated circuit between a first and second service termination points. Each service termination point generates a service performance report message. Each service performance report messages has information related to a performance of the service as determined by the service termination point generating the message. The service termination points exchange the service performance report messages over a service management channel to enable an assessment of the performance of the service based on the service performance report messages from both service termination points. Through access to and use of the service management channel, service providers can implement an edge management model or a core management model for measuring the performance of their services with respect to service level agreements governing those services.

Abstract: A processor includes controller circuitry operative to control the performance of a continuity check for each of a plurality of flows of protocol data units (PDUs) received by the processor. The controller circuitry is further operative to control access to a set of continuity check counters comprising a counter for each of the plurality of flows. The processor stores an identifier for each of a subset of the plurality of flows in a continuity check cache, and determines if a given flow for which a PDU is received in the processor has a corresponding entry in the continuity check cache. If the given flow has such an entry, the processor prevents a corresponding one of the continuity check counters from being updated, and if the given flow does not have such an entry, the processor clears the corresponding one of the continuity check counters and stores a flow identifier for the given flow in the continuity check cache.

Abstract: A simple admission control mechanism for IP based networks is provided. The decision on whether a new flow is accepted is based on the link load information on the paths from the source to destination. The new flow is accepted when the link load is less than a threshold. When at least one of the links on all of the available paths is larger than the acceptable threshold, access is denied to the flow. More than one threshold level may be used. Under the multiple threshold scenario, the traffic may be divided into different classes. The admission control mechanism helps to ensure a network that is not heavily congested.

Abstract: Echo messaging for operation, administration, and management of a service-based distribution path and associated services are disclosed. Service-based distribution paths or transport tunnels include services mapped or bound to a path associated with the transport tunnel. Echo messaging provides OAM capabilities to monitor the operational state of a service-based distribution path, including determining configuration, connectivity, and other characteristics of the path and associated services that transport data. OAM functions provided by echo messaging enable OAM functions despite service volume along a core network, path or set of paths.

Abstract: A device comprises interception means (2) capable, in the case of transfer of data packets between at least two remote terminals (Tij-k), via a communications network, of intercepting at least certain of the control packets during the transfer, and of determining amongst the intercepted control packets those which are formatted according to a chosen real-time data transfer control protocol, and management means (3) capable of duplicating at least part of each intercepted control packet, and of generating data, representing the duplicated part, intended to be communicated to control means (1) located in a control application (S) of the network.

Abstract: A system and method are disclosed for determining the minimum required processing speed for a quadrature decoder using measurements of encoder performance, and to assess the safety factor of a particular decoder processing speed. The system and method may also be used to indicate proper adjustment direction by displaying real-time error measurements during encoder alignment. The system measures a logic state width error and calculates alignment parameters, processing speed and a safety factor. The method allows a measured logic state width error to be used to calculate a minimum required processing speed and safety factor.

Abstract: Operations, administration and management (OAM) functions in a passive optical network (PON) can be performed by providing a system of flow points (i.e., software entities), such as those along the lines of the Maintenance End Points (MEPs) and Maintenance Intermediate Points (MIPs) described in the IEEE 801.1ag specification, which communicate connectivity fault test messages with each other. The flow points can be provided in the Optical Line Terminal (OLT) and Optical Network Terminator (ONT). Alternatively or in addition, flow points can be provided in a subscriber gateway coupled to the ONT. The flow points issue test messages, to which other flow points can respond with information regarding the state of network connectivity.

Abstract: A method for bit error rate measurements in a cell-based telecommunication system is presented, comprising the following steps of generating a first bit pattern at a first location of said telecommunication system, transmitting said first bit pattern from said first location to a second location of said telecommunication system, thereby obtaining a transmitted bit pattern, generating a second bit pattern at said second location, said second bit pattern being identical with the first bit pattern and comparing said transmitted bit pattern with said second bit pattern. The first bit pattern is transmitted in at least one unused cell (U, I), said unused cell (U, I) being generated during normal operation of said telecommunication system in the case of a lack of used cells to be transmitted.