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Transport Network OAM - Availability performance parameters ...

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Transport Network OAM - Availability performance parameters ...

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    1. Transport Network OAM - Availability performance parameters - Error performance parameters - Bringing-into-service and maintenance - Tandem connection monitoring - Fault and Performance Management Architectures within the Network Element Maarten Vissers February 2008

    2. 2 | Transport Network OAM, FM, PM| February 2008

    3. 3 | Transport Network OAM, FM, PM| February 2008

    4. 4 | Transport Network OAM, FM, PM| February 2008 Availability ratio and unavailability ratio (G.827) availability ratio (AR) is the proportion of time that a path is in the available state during an observation period. AR is calculated by dividing the total available time during the observation period by the duration of the observation period. unavailability ratio (UR) is the proportion of time that an end-to-end path is in the unavailable state during an observation period. UR is calculated by dividing the total unavailable time during the observation period by the duration of the observation period. observation period recommended to be one year outage intensity (OI) The number of outages (i.e. periods of unavailability ) per measurement period

    5. 5 | Transport Network OAM, FM, PM| February 2008 Criteria for entry and exit for the unavailable state (G.826, M.2100) A period of unavailable time begins at the onset of ten consecutive SES events. These ten seconds are considered to be part of unavailable time. A new period of available time begins at the onset of ten consecutive non-SES events. These ten seconds are considered to be part of available time. A bidirectional path or connection is in the unavailable state if either one or both directions are in the unavailable state.

    6. 6 | Transport Network OAM, FM, PM| February 2008 Error performance parameters (G.826) errored second ratio (ESR) The ratio of ES to total seconds in available time during a fixed measurement interval. severely errored second ratio (SESR) The ratio of SES to total seconds in available time during a fixed measurement interval. background block error ratio (BBER) The ratio of Background Block Errors (BBE) to total blocks in available time during a fixed measurement interval. The count of total blocks excludes all blocks during SESs. G.7710: Severely Errored Period Intensity (SEPI) The number of SEP events in available time, divided by the total available time in seconds during a fixed measurement interval.

    7. 7 | Transport Network OAM, FM, PM| February 2008 Error performance events (G.826, G.829) errored block (EB) A block in which one or more bits are in error. errored second (ES) A one-second period with one or more errored blocks or at least one defect. severely errored second (SES) A one-second period which contains = X% errored blocks or at least one defect. SES is a subset of ES. background block error (BBE) An errored block not occurring as part of an SES. consecutive severely errored second (CSES) period A sequence of between three to nine consecutive SES. The sequence is terminated by a second, which is not a SES.

    8. 8 | Transport Network OAM, FM, PM| February 2008 QoS performance parameters and NE measurements (G.7710)

    9. 9 | Transport Network OAM, FM, PM| February 2008 Bringing into service (M.2110) For bringing transmission entities into service, several tests are necessary according to the concerned transmission entity. These tests consist of recording the number of occurrences of performance events over a certain duration and comparing the result with a limit value. Limit values are different according to the type of tests and the tested transmission entity. These limits are defined for each performance event and for each test in the specific technology Recommendations. Tests 15 m, 2 h and 24 h should be applied to each direction of transmission. Wherever possible, the per-direction measurement configuration should be used. For a bidirectional path or section, the test is considered passed if both directions meet the limits, or failed if either direction fails the limit.

    10. 10 | Transport Network OAM, FM, PM| February 2008 Bringing into service (M.2110) Continuity test This test consists of verifying the continuity of the link, during a short period of time (15 minutes maximum). For a per-direction measurement, the continuity test consists of sending bit errors with a test set at both termination points. Test15m This test consists of recording the number of occurrences of each performance event for a time period of 15 minutes and comparing the result with a single limit value, named S15. Test2h This test consists of recording the number of occurrences of each performance event for a time period of 2 hours and comparing the result with a single limit value, named S2. Test24h This test consists of recording the number of occurrences for each performance event for a time period of 24 hours and comparing the result with a single limit value, named S24.

    11. 11 | Transport Network OAM, FM, PM| February 2008 Maintenance limits and System restoration limit (M.2100) Once entities have been placed into service, supervision of the network requires additional limits, as described in ITU-T M.20. This supervision is done on an in-service basis using performance monitoring equipment. The supervision process involves analyzing anomalies and defects detected by maintenance entities to determine if the performance level is normal, degraded, or unacceptable. A limit on performance after intervention (repair) is required; it is equal to the BIS limit.

    12. 12 | Transport Network OAM, FM, PM| February 2008 Performance limits for maintenance (M.2100) Unacceptable performance level An unacceptable performance level is defined in ITU-T M.20. The unacceptable performance limit for a given entity is derived from an objective of at least 10 times the APO during a 15-minute period. Degraded performance level A degraded performance level is defined in ITU-T M.20. The degraded performance limit for a given entity is derived from an objective on the order of 0.5 times the APO for transmission systems and 0.75 times the APO for paths. The monitoring duration is a fixed duration of 24 hours. Performance limit after intervention (repair) This performance limit is derived from an objective in the order of 0.125 times the APO for transmission systems and the same as the BIS limit for paths (see ITU-T M.35 and ITU-T M.2110).

    13. 13 | Transport Network OAM, FM, PM| February 2008 Performance thresholds (M.2100) Performance limits are defined for ES and SES. Each performance level will have its own threshold to detect crossing of the limit and will require its own measurement duration. Use of thresholds The general strategy for the use of performance monitoring information and thresholds is described in ITU-T M.20 and ITU-T M.34. These thresholds and information will be reported to operations systems via the TMN for both real time and longer term analysis. When thresholds of unacceptable or degraded performance levels are exceeded, maintenance action should be initiated independently of the performance measurement. Other thresholds may be used for longer term quality analysis. The operations systems will use real-time processing to assign maintenance priorities to these thresholds and information, using the performance supervision process described in ITU-T M.20. Thresholds based on a T1 evaluation period The monitoring duration T1 is 15-minutes and ES and SES are counted over this period. The T1 period is to assist in detection of transition to or from the unacceptable performance. A threshold report occurs when an ES or SES threshold is met or exceeded. The reset threshold report, which is an optional feature, occurs when the number of ES and SES is lower than or equal to the reset threshold. Those principles are explained in ITU-T M.2120. Thresholds based on a T2 evaluation period The monitoring duration T2 is fixed to a 24-hour value. The T2 period is to assist in detection of transition to the degraded performance. A threshold report occurs when an ES or SES threshold is met or exceeded over the period of time T2 as explained in ITU-T M.2120.

    14. 14 | Transport Network OAM, FM, PM| February 2008 Tandem connection monitoring (G.805) A tandem connection represents the part of a trail that requires monitoring independently from the monitoring of the complete trail. In this role, the following functions may be required by the tandem connection tandem connection near end fault management and performance monitoring (error performance and failure/alarm conditions); tandem connection far end fault management and performance monitoring (error performance and failure/alarm conditions); tandem connection monitoring independent of incoming server signal fail indication (AIS, FDI); tandem connection incoming signal fail indication (signal fail before the tandem connection); tandem connection connectivity verification (i.e. trace) (between the ends of the tandem connection); tandem connection continuity verification (i.e. loss of signal, unequipped, loss of continuity) (between the ends of the tandem connection); tandem connection near end outgoing signal monitoring in order to allow localization of faults and errors in white spot areas between two successive tandem connection domains; tandem connection far end outgoing signal monitoring in order to allow localization of faults and errors in white spot areas between two successive tandem connection domains; tandem connection idle signal (including idle signal identity).

    15. 15 | Transport Network OAM, FM, PM| February 2008 Three applications of tandem connections (G.805) serving operator administrative domain (e.g. public network domain, network operator domain, network operator subnetwork domain) A tandem connection that measures the quality of the service delivered to the customer. A serving operator administrative domain supporting tandem connection has its source as close as possible behind the NNI/UNI and its sink as close as possible in front of the NNI/UNI; protected domain (e.g. sublayer monitored SNC protection) A tandem connection that measures the defect status of the working and protection connections. A protected domain supporting tandem connection has its source behind the protection switch bridge and its sink in front of the protection switch selector functions; service requesting administrative domain (e.g. user domain) A tandem connection that measures the quality of the service received from the operator. A service requesting administrative domain supporting tandem connection has its source as close as possible in front of the UNI/NNI and its sink as close as possible behind the NNI/UNI.

    16. 16 | Transport Network OAM, FM, PM| February 2008 Performance data collection (G.7710)

    17. 17 | Transport Network OAM, FM, PM| February 2008 Near-end and Far-end concepts

    18. 18 | Transport Network OAM, FM, PM| February 2008 Fault Management and Performance Monitoring Architecture anomaly (nXXX) defect (dXXX) fault cause (cXXX) failure (fXXX)

    19. 19 | Transport Network OAM, FM, PM| February 2008

    20. 20 | Transport Network OAM, FM, PM| February 2008

    21. 21 | Transport Network OAM, FM, PM| February 2008

    22. 22 | Transport Network OAM, FM, PM| February 2008 Fault Management inside the EMF (G.7710)

    23. 23 | Transport Network OAM, FM, PM| February 2008

    24. 24 | Transport Network OAM, FM, PM| February 2008

    25. 25 | Transport Network OAM, FM, PM| February 2008 Access to OAM PDUs in T-MPLS networks

    26. 26 | Transport Network OAM, FM, PM| February 2008 OAM MEG level and label/VLAN ID based filtering

    27. 27 | Transport Network OAM, FM, PM| February 2008 T-MPLS Basic functions and processes

    28. 28 | Transport Network OAM, FM, PM| February 2008 T-MPLS Frame structures

    29. 29 | Transport Network OAM, FM, PM| February 2008 References M.2100 Performance limits for bringing-into-service and maintenance of international multi-operator PDH paths and connections M.2110 Bringing into service international multi-operator paths, sections and transmission systems G.826 End-to-end error performance parameters and objectives for international, constant bit-rate digital paths and connections G.827 Availability performance parameters and objectives for end-to-end international constant bit-rate digital paths G.829 Error performance events for SDH multiplex and regenerator sections G.805 Generic functional architecture of transport networks G.806 Characteristics of transport equipment – Description methodology and generic functionality G.7710 Common equipment management function requirements

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