1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0100506.1997(R2011) Network Performance Switched Exchange Access Network Transmission Specifications ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven stand
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9、retations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodi
10、cally 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 terminating (egress) refers to the bi-directional transmission channe
11、l between an interexchange carrier POT and the called partys serving end office. The performance specifications are given in terms of acceptance limits, restoral limits, and immediate action limits. In-service parameter performance will be distributed statistically. The actual parameter performance
12、is characterized by the parameter distributions and not by the limits alone. On this basis, although the parameter distributions are not requirements of this standard, network providers and equipment vendors should take into account the parameter distributions as well as the individual trunk limits
13、in their plans and designs. The statistics in annex A reflect an estimate of the characteristics of the statistical distributions that are expected for a large number of channels. 1.2 Purpose This standard is intended to be used by the telecommunications industry to provide high-quality service to e
14、nd users. The use of this standard helps to assure the ICs about the quality of exchange access services and to provide exchange carriers with the ability to implement and maintain the exchange access network. This standard is a product of a number of considerations. Among them are customer service
15、perception, network architectures (see SR-TSV-002275 and GR-334-CORE. See annex C), the technical capabilities of transmission and switching systems (see TR-NPL-000037 and Analog voice and voiceband data transmission performance characterization of exchange access plant) and terminal equipment (as d
16、escribed in ANSI/EIA 470-A-1987), as well as operational and economic concerns. Some of these considerations are discussed in annex B. ATIS-0100506.1997 2 1.3 Application 1.3.1 Architecture This standard applies to switched exchange access provided by an EC to an IC between an EC end office and a PO
17、T. Switched exchange access service is an element of voicegrade service similar to that provided in what has historically been referred to as the “public switched network.“ This network allows for direct and tandem switched connections between an end office and a POT. The standard provides one set o
18、f requirements between the end office and the POT that apply independent of routing of the call through the exchange carriers network. Guidelines are provided between the POT and the EC access tandem (AT). Figure 1 Illustration of the various portions of a typical end-to-end connection, showing the
19、relationship of exchange access portions to service providers When the standard was developed, the arrangement was modeled after the capabilities of a service offering provided by many ECs and identified as Feature Group D. However, the standard is intended to be completely generic and may apply to
20、future EC service offerings. For arrangements that differ from the original Feature Group model used to develop this standard, values for absolute delay and other performance parameters, such as post-dialing delay, need to be considered. Moreover, arrangements involving more than one EC between a PO
21、T and an end office were not evaluated in developing this standard. Such arrangements require further study. 1.3.2 Facilities This standard applies generally to digital facilities and limited-mileage cable facilities. (In all cases, guidelines are not part of ANSI T1.506.) Specifically, it covers ch
22、annels provided by the following facilities and combinations: a) 64-kbit/s pulse code modulation (PCM) systems using 8-bit encoding, with or without Robbed-Bit signaling, and a -law characteristic with =255. Examples are channels using newer-design digital systems (D2, D3, D4, D5 channel banks, or t
23、heir equivalent) on wire, radio, or fiber media; b) Digital facilities of any length with cable extensions that are 1 mile or less in length; c) Cable that is 1 mile or less in length; d) Any combination of the above facility types, with or without intermediate switching (total cable not to exceed 1
24、 mile in length). The limits reflect the transmission performance capabilities of newer-design digital facilities (D2, D3, D4, D5 channel banks or their equivalent). Excluded are the early-design 7-bit PCM systems (such as D1 or the equivalent) and low-bit-rate-encoding systems such as 32-kbit/s ada
25、ptive differential pulse code modulation (ADPCM) systems. Cable facilities and cable extensions of 1 mile or less are included since they are sufficiently short to allow the combined facility to approximate the performance of a digital facility alone. ATIS-0100506.1997 3 The development of this stan
26、dard did not include the effects of systems such as digital cross-connect systems (DCS). Deployment of such systems may increase impairments such that exchange access service may not meet requirements. This document specifies performance limits and allows for numerous architecture configurations and
27、 facility and switch combinations applicable to exchange access services. The actual facilities and switches used to provide service are a function of the existing telephone plant and may be influenced by the location of the POT. The existing telephone plant may vary by geographical area and between
28、 any pair of points within a geographical area (i.e., both analog and digital facilities may coexist between the same two points). Therefore, not all the specific facilities and combinations described in this standard might be offered or available between all point pairs within an EC area. It is rec
29、ommended that if cases arise that have not been addressed in this standard, the EC and the IC cooperate to negotiate needed requirements. This standard does not include the effects of low-bit-rate encoding techniques such as those employed in 32-kbit/s ADPCM as specified in ANSI T1.302-1989, and ITU
30、-T Recommendation G.726. A separate standard, ANSI T1.501, deals with the performance impact and deployment guidelines for ADPCM. This exchange access standard is independent of ADPCM deployment. In addition to the requirements of this standard, the deployment guidelines contained in ANSI T1.501 are
31、 needed to control service performance. 1.3.3 Measurements This document provides specifications for a set of analog parameters that relate to voice and voiceband data network performance between an end office and a POT. The numerical values contained in this standard include the contributions of di
32、gital-to-analog (D/A) conversion at a digital POT as found in commonly used channel banks. These numerical values, however, do not include the contribution of impairments caused when digital loss is placed in the measurement path to the test terminations of a digital AT or digital IC switch. For fur
33、ther information on the effect of digital loss pads, see annex B. As discussed in 1.3.3.1 and 1.3.3.2, measurements can be made using analog or digital methods. Further, under specific conditions, measurements can be made switch-to-switch. 1.3.3.1 Measurement method analog At an analog test access p
34、oint, the parameters may be measured directly, using methodologies defined in ANSI/IEEE 743. At a digital POT, using analog measurement methods, specifications in this standard apply to measurements that include encoding or decoding with a 4-wire D4 channel bank, or equivalent, except that its contr
35、ibution to the loss measurement error shall be less than 0.1 dB. (See Digital Channel Bank Requirements and Objectives. See annex C.) 1.3.3.2 Measurement method digital Measurements of analog parameters that are performed directly on a digital bit stream at the DS0 rate (64 kbit/s) may use a technol
36、ogy that does not contribute significant degradations that are associated with the D/A conversion process. It follows that the results of such measurements should generally be better than, or at least equal to, those that would be obtained after such a conversion. Therefore, the specifications in th
37、is document can be used as bounds or guidelines for digital measurements. This standard does not provide guidelines for discounting the effects of digital-to-analog conversion on the analog specifications. Note that the digital measurement method is not covered in ANSI/IEEE 743, but is commonly used
38、 in remote measuring systems. 1.3.3.3 Switch-to-switch testing The specific recommended numeric values contained in the requirements clauses 4 and 5 in the standard apply between the end office and the POT. However, testing is usually most conveniently done switch-to-switch. If the IC switch is co-l
39、ocated with the POT, the standard may be used as the basis for switch-to-switch testing after accounting for the effect of the IC switch and office wiring, if any. If the switch and POT are not co-located, the switch-to-switch analog test results may need to be corrected by ATIS-0100506.1997 4 compe
40、nsating for the contribution of the IC transmission facilities between the POT and the test position at the IC switch. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of pub
41、lication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. ANSI T1.302-1989 (R1996), Teleco
42、mmunications Digital processing of voice-band signals Line format for 32-kbit/s adaptive differential pulse-code modulation (ADPCM) ANSI T1.501-1994, Telecommunications Network performance Tandem encoding limits for 32-kbit/s adaptive differential pulse-code modulation (ADPCM) ANSI/IEEE 743-1995, St
43、andard equipment requirements and measurement techniques for analog transmission parameters for telecommunications ITU-T Recommendation G.726, Telecommunications Digital processing of voice-band signals Algorithms for 24-, 32-, and 40-kbit/s adaptive differential pulse-code modulation (ADPCM) 1)3 De
44、finitions The following definitions apply in this standard: 3.1 acceptance limit (AL): The bound on performance that is allowed at service turn-up or acceptance of a circuit or connection by the IC, or when corrective action is taken to restore a parameter after a failure of the immediate action lim
45、it (IAL). Performance as measured by a parameter is satisfactory if the value of the parameter is equal to or better than the limit. 3.2 access line (loop): A channel between an end users network interface and local end office. 3.3 access tandem (AT): An exchange carrier switching system that provid
46、es a traffic concentration and distribution function for inter-LATA traffic originating or terminating within a LATA. 3.4 channel: A transmission path between two points (one or both points may be a POT or NI). The term channel may refer to a unidirectional path or a bi-directional path. 3.5 connect
47、ion: A temporary concatenation of transmission channels or telecommunication circuits, switching, and other functional units set up to provide for a transfer of information between two or more points in a telecommunication network. 3.6 end office (EO): An exchange carrier switching system where acce
48、ss lines (loops) are terminated for purposes of interconnection to each other and to trunks. 3.7 end user (EU): The calling party, or the called party, or both involved with a switched telecommunications connection. Customers who use (rather than provide) telecommunication services are end users. 3.
49、8 exchange carrier (EC): The telecommunications common carrier franchised to provide service in specific geographic areas. 1)Available from the American National Standards Institute, 11 West 42nd Street, New York, NY 10036. ATIS-0100506.1997 5 3.9 immediate action limit (IAL): The bound on performance allowed for a circuit or connection that is in service. When any parameter value exceeds the IAL, the circuit or connection is considered defective and corrective action is necessary. 3.10 interexchange carrier (IC): A carrier that provides telecommunication service
