Abstract: A method and corresponding apparatus for diagnosing problems on a time division multiple access (TDMA) optical distribution network (ODN) is provided. An example method may include: (i) measuring no-input signal power level on a communications path configured to carry upstream communications between multiple optical network terminals (ONTs) and an optical line terminal (OLT) in a passive optical network (PON) at a time no upstream communications are on the communications path from the ONTs to the OLT; (ii) comparing the measured no-input signal power level to a threshold; and (iii) generating a notification in an event the threshold is exceeded. Through the use of this method, faults in optical transmitters, such as bad solder joints, can be determined. Such faults may cause errors in parameters, such as ranging or normalization parameters, associated with communications. By determining the faults, the time required to resolve communications errors can be reduced.

Abstract: Component malfunctions in passive optical networks (PON) can increase bit error rates and decrease signal-to-noise ratio of communications signals. These faults may cause the receivers of the signals, either the optical line terminal (OLT) or optical network terminals (ONTs), to experience intermittent faults and/or may result in misinterpreted commands that disrupt other ONT's communication, resulting in a rogue ONT condition. Existing PON protocol detection methods may not detect these types of malfunctions. An embodiment of the present invention identifies faults in a PON by transmitting a test series of data patterns via an optical communications path from a first optical network node to a second optical network node. The test series is compared to an expected series of data patterns. An error rate may be calculated as a function of the differences between the test series and expected series. The error rate may be reported to identify faults in the PON.

Abstract: A method and corresponding apparatus is disclosed for determining a particular Optical Network Terminal (ONT) in a Passive Optical Network (PON) is malfunctioning by sending a continuous stream of light up a shared fiber, which results in adversely affecting communications between the ONT and an Optical Line Terminal (OLT). The example embodiment verifies the failure is due to a faulty optical transmitter in the ONT and not a different network fault, such as a fiber optic line cut or power outage. Through the use of the example embodiment, a service provider can determine in an automated manner which specific ONT of a PON is malfunctioning.

Abstract: Component malfunctions in passive optical networks (PON) can increase bit error rates and decrease signal-to-noise ratio of communications signals. These faults may cause the receivers of the signals, either the optical line terminal (OLT) or optical network terminals (ONTs), to experience intermittent faults and/or may result in misinterpreted commands that disrupt other ONT's communication, resulting in a rogue ONT condition. Existing PON protocol detection methods may not detect these types of malfunctions. An embodiment of the present invention identifies faults in a PON by transmitting a test series of data patterns via an optical communications path from a first optical network node to a second optical network node. The test series is compared to an expected series of data patterns. An error rate may be calculated as a function of the differences between the test series and expected series. The error rate may be reported to identify faults in the PON.

Abstract: Jitter in a clock signal can cause communications faults in communications networks, such as in networks in which downstream nodes use recovered clock signals as timing for upstream communications. An embodiment of the present invention detects and compensates for jitter in a network by recovering a reference clock associated with communications signals between nodes, such as an Optical Line Terminal (OLT) and Optical Network Terminal (ONT) in a Passive Optical Network (PON). A local clock is synchronized with the reference clock. Jitter induced faults may be detected and compensated for by increasing the synchronization rate, then decreasing the synchronization rate until jitter induced faults begin to occur. A loss or change in a rate of communications errors occurring as a function of the synchronization rate may be monitored and reported to a system operator. Compensating for jitter by adjusting the synchronization rate provides for robust communications between network nodes.

Abstract: Malfunctions in a communications network may introduce an unacceptably low level of reliability for many users, thereby slowing further adoption of Internet Protocol (IP) telephony, for example. In an example embodiment of the present invention, a method and corresponding apparatus for supporting a call in a presence of a fault in a network is provided. The method includes supporting a primary protocol to service a call between near-end and far-end access nodes associated with two or more callers. Signaling information in the primary protocol supporting the call may be identified and used to establish a backup protocol between the near-end and far-end access nodes. The primary protocol may be monitored for a fault and, in an event a fault occurs, supporting the call using the backup protocol. As a result, IP telephony may be transported in a more reliable manner, thereby reducing the number of dropped and uncompleted calls.

Abstract: A Session Initiation Protocol (SIP) network can malfunction or be incorrectly provisioned in such a way that an Optical Network Terminal (ONT) cannot perform SIP operations and complete SIP voice path calls between the ONT voice port and the SIP network. Accordingly, a technique for validating SIP operations is provided which (i) verifies locally stored SIP operation parameters are currently valid, (ii) initiates an SIP session with a known SIP validation endpoint in an event the locally stored SIP operation parameters are verified to be currently valid, and (iii) reports results of the verifying of the locally stored SIP operation parameters or the initiating of the SIP session. By validating SIP operation parameters, the ONT maintains its state of readiness to support SIP sessions, such as in-coming or outgoing normal or emergency 9-1-1 voice calls.

Abstract: An apparatus and a method for verifying optical system performance using a signaling value test are disclosed. After instructing the first optical interface device and the second optical interface device to enter a verification mode, the first optical interface device sends first verification data to the second optical interface device via an optical communications network. In one embodiment, the first optical interface device is an optical line termination (“OLT”) and the second optical interface device is an optical network terminal (“ONT”). Upon composing the first reply message in response to content received by the second optical interface in accordance with the first verification data, the second optical interface device forwards the first reply message to the first optical interface device.

Abstract: An apparatus and a method of enhancing data integrity for data transmission over an optical network are disclosed. Upon detecting a low performance condition associated to the optical communications network, an error correcting code (“ECC”) device is activated. The ECC device inserts the ECC to a data stream to form an ECC data stream. Once the ECC data stream reaches to the destination, the ECC device corrects any errors incurred during the transmission, and removes the ECC from the ECC data stream. It should be noted that the ECC device can also be activated by a request from a network operator.

Abstract: Component malfunctions in passive optical networks (PON) can increase bit error rates and decrease signal-to-noise ratio in communications signals. These faults may cause the receivers of the signals, either the optical line terminal (OLT) or optical network terminals (ONTs), to experience intermittent faults and/or may result in misinterpreted commands that disrupt other ONT's communication, resulting in a rogue ONT condition. Existing PON protocol detection methods may not detect these types of malfunctions. An embodiment of the present invention identifies faults in a PON by transmitting a test series of data patterns via an optical communications path from a first network node to a second network node. The test series is compared to an expected series of data patterns. An error rate may be calculated as a function of the differences between the test series and expected series. The error rate may be reported to identify faults in the PON.

Abstract: Jitter in a clock signal can cause communications faults in communications networks, such as in networks in which downstream nodes use recovered clock signals as timing for upstream communications. An embodiment of the present invention detects and compensates for jitter in a network by recovering a reference clock associated with communications signals between nodes, such as an Optical Line Terminal (OLT) and Optical Network Terminal (ONT) in a Passive Optical Network (PON). A local clock is synchronized with the reference clock. Jitter induced faults may be detected and compensated for by increasing the synchronization rate, then decreasing the synchronization rate until jitter induced faults begin to occur. A loss or change in a rate of communications errors occurring as a function of the synchronization rate may be monitored and reported to a system operator. Compensating for jitter by adjusting the synchronization rate provides for robust communications between network nodes.

Abstract: A fault condition of a continuous stream of light up a shared fiber from an Optical Network Terminal (ONT) to an Optical Line Terminal (OLT) may adversely affect ranging of the ONT by the OLT. A method and corresponding apparatus for ranging an ONT tolerant to such a fault condition is disclosed. In an example embodiment, an optical receiver of an Optical Line Terminal (OLT) is reset at about a time a ranging signal from an ONT is expected to be received. Through the use of the example embodiment, an ONT can be ranged in the presence of a rogue ONT causing the fault condition. Moreover, the example embodiment enables the rogue ONT to be ranged in a presence of the fault condition and an Optical Distribution Network (ODN), which includes the OLT and the rogue ONT, to continue to support communications in a presence of the fault condition.

Abstract: A method and corresponding apparatus for diagnosing problems on a time division multiple access (TDMA) optical distribution network (ODN) is provided. An example method may include: (i) measuring no-input signal power level on a communications path configured to carry upstream communications between multiple optical network terminals (ONTs) and an optical line terminal (OLT) in a passive optical network (PON) at a time no upstream communications are on the communications path from the ONTs to the OLT; (ii) comparing the measured no-input signal power level to a threshold; and (iii) generating a notification in an event the threshold is exceeded. Through the use of this method, faults in optical transmitters, such as bad solder joints, can be determined. Such faults may cause errors in parameters, such as ranging or normalization parameters, associated with communications. By determining the faults, the time required to resolve communications errors can be reduced.

Abstract: A method and corresponding apparatus is disclosed for determining a particular Optical Network Terminal (ONT) in a Passive Optical Network (PON) is malfunctioning by sending a continuous stream of light up a shared fiber, which results in adversely affecting communications between the ONT and an Optical Line Terminal (OLT). The example embodiment verifies the failure is due to a faulty optical transmitter in the ONT and not a different network fault, such as a fiber optic line cut or power outage. Through the use of the example embodiment, a service provider can determine in an automated manner which specific ONT of a PON is malfunctioning.

Abstract: An error in a passive optical network is identified by communicating to an optical network terminal on the passive optical network a request to transmit a response signal at a predetermined power level, receiving the response signal in response to the request, and measuring a power level of the response signal. A predetermined channel power level is compared to the power level of the response signal and a status of the optical network terminal is determined based on the result of the comparison.