1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0100503.2002(R2011) Network Performance Parameters for Dedicated Digital Services Definitions and Measurements ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-dr
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10、en periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer T1A1.3 Chair Henri Suyderhoud, OKI America, Incorporated; T
11、1A1.3 Vice-Chair Organization Represented Name of Representative Oscar Avellaneda Nortel Networks Ken Biholar Alcatel USA John Boal MEGAXESS, Inc. Dick Bobilin Acterna David Brady BellSouth Rick Canaday AT Performance allocation among network elements; and Compatibility of performance measurements a
12、mong network users, providers, and equipment vendors. This document provides the framework for a companion document, T1.510-1999, Network performance parameters for dedicated digital services, which contains numerical specifications and allocations for the parameters and measurements discussed in th
13、is standard. End users may use the concepts developed in this standard to measure end-user-to-end-user performance and availability. 2 Normative References The following standard contains provisions, which, through reference in this text, constitute provisions of this American National Standard. At
14、the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this American National Standard are ATIS-0100503.2002 2 encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
15、 T1.510-1999, Network Performance Parameters for Dedicated Digital Services for Rates Up to and Including DS3 Specifications.13 Abbreviations, Acronyms, and Definitions 3.1 Abbreviations Auni(b,a): unidirectional availability for INIb INIa; Auni(A,B): unidirectional availability for NIA NIB; Auni(B,
16、A): unidirectional availability for NIB NIA. Auni(A,a): unidirectional availability for NIA INIa; and Auni(a,A): unidirectional availability for INIa NIA. Interactive services are bi-directional in nature and are unusable (i.e., unavailable) if either direction of transport is unavailable. For servi
17、ces that are bi-directional, end-to-end bi-directional service availability is defined as: Abi(AB): bidirectional availability for NIA NIBwhere Abi(AB)= Auni(A,B) Auni(B,A)and is the Intersection operator. Note that bi-directional availability is end-to-end and cannot be allocated. 5.2.2 Determinati
18、on of bidirectional availability There must be some method to determine the periods of time when both directions of a bidirectional service are in the available state. One method of providing this functionality is to require time-stamping of the transitions to available and unavailable states as a n
19、ew feature. Another method is to implement the bidirectional UAS register as specified in ITU-T Recommendation G.784.8Additional methods to assess bidirectional availability are for further study. 8For the title and availability information of this cross-reference, see Annex A ATIS-0100503.2002 8 6
20、Measurements 6.1 Measurement purposes The following measurements and tests are made to verify long-term service performance: a) Acceptance tests: These measurements verify that the value of the performance parameters are within prescribed limits after the completion of a new service installation. Th
21、e measurements for these tests are performed on an out-of-service basis. b) Trouble verification tests: These tests verify the need for maintenance activity, in response to a trouble report. The measurements for these tests are performed on either an in-service or an out-of-service basis. c) Repair
22、verification tests: These tests verify that the values of the performance parameters are within the prescribed limits after completion of a repair activity. The measurements for these tests are generally performed on an out-of-service basis. d) Service monitoring: These measurements verify that the
23、values of the performance parameters are within the prescribed limits. These in-service measurements are performed on a continuous or periodic basis. e) Characterization measurements: These measurements collect data for determining the performance of a specific population (defined by rate, facility
24、type, and other characteristics). These measurements are performed on either an in-service or an out-of-service basis. 6.2 Types of measurements The parameters can be measured in the following ways: a) Inservice measurements: These measurements are performed without disturbing user information trans
25、missions; and b) Out-of-service measurements: These measurements require the service to be made unavailable to the user. 6.3 Performance determination Performance determination is based on the following relationships: a) Z number of intervals of length Q are examined where: 1) Z is an integer value;
26、 and 2) Q is an interval of time or a fixed number of bits corresponding to the event under consideration. c) For each interval Q examined, a determination is made as to whether a threshold value W for the event has been exceeded where W is a threshold of transmission bit or block errors over interv
27、al Q corresponding to the event under consideration; d) Performance for the parameter under consideration is determined by the number of intervals (events) Y, out of Z intervals examined, which cross the threshold W. ATIS-0100503.2002 9 Table 1 shows the relationship of the accuracy events to the in
28、tervals and thresholds. Table 1 Relationship of the accuracy events to the intervals and thresholds Event Interval (Q) Threshold (W) Errored Unit of Time Unit time Zero Errors Errored Block Block length (time or number of bits) Zero Errors Severely Errored Unit of Time Unit time Block error count ov
29、er interval Q corresponding to 30% (see Note) errored blocks (where a suitable block is not available, 10-3BER) or 1 SDP Severely Errored Period 3 unit times while in the available state 100% SEUT (a non-SEUT stops the sequence) NOTE - The errored block threshold for defining an SES (SEUT where the
30、unit of time is 1 second) for SDH sections is different from 30% and typically lower. 6.4 In-service measurement of availability With availability defined in Availability parameters above, the monitoring points should be at INIs and NIs. 6.4.1 Measuring availability between two INIs To measure Avail
31、ability between INIs9, monitoring points are at the INI located at both ends of the transit portion of the transmission path. As shown in Figure 2, each end has two monitoring points: one for transmitting and one for receiving. Four monitoring points are available for measuring unidirectional availa
32、bility performances. Figure 2 Monitoring points for availability between two INIs 9Multiple INIs are possible within the transit portion. The monitoring points shown in Figure 2 are applicable to any pair of INIs. ATIS-0100503.2002 10 Measuring availability from NI-to-NI Similarly, the Availability
33、from NI to NI (see Figure 3), could be measured using test access points at A, B, F, and H. However, in some instances, A, B, F, and H are not accessible to the service provider. For these situations, availability can only be measured if a Far-End Monitoring Capability is supported by the customer p
34、remise equipment. With only monitoring point C, D, E, and G accessible, performance primitives required for availability measurements (e.g., ES, SES, etc.) in the incoming direction are reported to the far-end via special messages embedded within the signal format (see T1.231-1997). Examples include
35、 the far-end block error (FEBE) indicators in SONET and DS3 C-bit applications, and the performance report message (PRM) in DS1-ESF. With such capability built into a transmission signal, part of the monitoring functions (derivation, storage, thresholding, and reporting of performance primitives and
36、 parameters) for transmission performance observed at the far-end can be provided at the near-end. Figure 3 Monitoring points for availability from NI-to-NI ATIS-0100503.2002 11 Annex A (informative) A Bibliography T1.101-1999, Synchronization interface standard.1T1.102-1993 (R1999), Digital Hierarc
37、hy- Electrical Interfaces.1T1.105-2001, Synchronous optical network (SONET) Basic description including multiplex structure, rates, and formats.1T1.107-2002, Digital hierarchy Formats specifications.1T1.231-1997, Digital hierarchy Layer 1 in-service digital transmission performance monitoring.1T1.41
38、0-2001, Carrier to Customer Metallic Interface - Digital Data at 64 kbit/s and Subrates.1T1.507-2002, Network performance parameters for circuit-switched digital services Definitions and measurements.1T1.514-2001, Network Performance Parameters and Objectives for Dedicated Digital Services SONET bit
39、 rates.1T1.TR.51-1996, A Technical Report on Changes in the Network Access Model.1ITU-T Recommendation G.701 (3/93), Vocabulary of digital transmission and multiplexing, and pulse code modulation (PCM) terms.10ITU-T Recommendation G.784 (07/99), Synchronous digital hierarchy (SDH) management.10ITU-T
40、 Recommendation G.821 (08/96), Error performance on an international digital connection forming part of an integrated services digital network.10ITU-T Recommendation G.821 Corrigendum 1 (07/01), Error performance on an international digital connection forming part of an integrated services digital n
41、etwork.10ITU-T Recommendation G.822 (11/88), Controlled slip rate objectives on an international digital connection.10ITU-T Recommendation G.826 (02/99), Error performance parameters and objectives for international, constant bit rate digital paths at or above the primary rate.10ITU-T Recommendation
42、 G.826 Corrigendum 1 (07/01), Error performance parameters and objectives for international, constant bit rate digital paths at or above the primary rate.1010This document is available from the International Telecommunications Union. ATIS-0100503.2002 12 ITU-T Recommendation G.827 (03/00), Availabil
43、ity parameters and objectives for path elements of international constant bit-rate digital paths at or above the primary rate.10ITU-T Recommendation G.827.1 (11/00), Availability parameters and objectives for path elements of international constant bit-rate digital paths at or above the primary rate
44、.10ITU-T Recommendation G.828 (03/00), Error performance parameters and objectives for international, constant bit rate synchronous digital paths.10ITU-T Recommendation G.828 Corrigendum 1 (07/01), Error performance parameters and objectives for international, constant bit rate synchronous digital paths.10ITU-T Recommendation X.21 (9/92), Interface between data terminal equipment and data circuit-terminating equipment for synchronous operation on public data networks.10ITU-T Recommendation X.140 (9/92), General quality of service parameters for communication via public data networks.10
