1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0100517.1995(R2011) ISDN performance Parameters their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not co
2、nforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in
3、the name of the American National Standards Institute. Requests for interpretations 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 CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time.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
4、American National Standards Institute require that action be taken 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 Discla
5、imer planned revisions to this standard will address other ISDN bearer services (e.g., n 64 kbit/s). Practical methods for measuring ISDN parameter values will be specified in a planned supplement to this standard. For each ISDN bearer service, performance is considered in the context of the 33 perf
6、ormance matrix de-fined in American National Standard for Information systems Data communication systems and services User-oriented performance parameters, ANSI X3.102-1992 (see figure 1). Three protocol-independent data communication functions are identified in the matrix: access, user information
7、transfer, and disengagement. Each function is considered with respect to three general performance concerns (or “performance criteria“): speed, accuracy, and dependability. This standard defines a comprehensive set of primary parameters that describe performance relative to each function and criteri
8、on. The objectives specified for the primary pa-rameters apply only to connections in the available state. A two-state model provides a basis for describing overall service availability. A specified availability function compares the values for a set of “supported“ pri-mary parameters with correspon
9、ding outage thresholds to classify the service as “available“ (no service out-age) or “unavailable“ (service outage). This standard specifies the availability function and defines the avail-ability parameters that characterize the resulting binary random process. The parameters defined in this stand
10、ard may be used to specify or measure the performance of end-to-end ISDN connections or connection portions. This standard defines two general ISDN connection portion types: access portions and transit portions. These portions are delimited on the basis of jurisdictional boundaries between carriers
11、and corresponding jurisdictional boundaries between carrier facilities and customer prem-ises equipment. This standard defines worst-case objectives for each portion type. The measurement meth-ods that will be defined in a supplement to this standard will be applicable in direct measurements at the
12、de-fined jurisdictional boundaries or may be used to estimate performance at jurisdictional boundaries on the basis of observations made at adjunct functional boundaries (e.g., switch locations), taking account of known characteristics of the access or transit links that connect equipment in separat
13、e jurisdictions. ATIS-0100517.1995 2 FunctionDependabilityAccuracySpeedCriterionAccessUserInformationTransferDisengagementAvailabilityFunctionPRIMARYPARAMETERSServiceAvailable(No Outage)ServiceUnavailable(Outage)PrimaryParameterValuesFigure1-3x3performancematrixframeworkFigure 1 3 3 performance matr
14、ix framework ATIS-0100517.1995 3 All values specified in this standard (with the exception of table 14) are based on (and only apply under) the following assumptions: values for primary performance parameters exclude performance observed during periods of unavail-ability; for each connection portion
15、 type, the ten worst-performing days in a calendar year are excluded. In the context of this standard, the term, worst-case, means that the design objectives should be met by all portions of any end-to-end connection configured and used in accordance with the conditions and assump-tions identified i
16、n this standard. The design objectives specified in this standard may not be achievable in all network configurations existing at the time of its publication. They represent agreements among service providers and end users applicable to the planned evolution of ISDN bearer services and their interco
17、nnection. The actual values achieved in a connection portion will depend on many factors, including the traffic expected and actually offered, the inter-nal network topology, and the signalling rates on the access and internetwork circuit sections. Variation away from the worst-case value for each f
18、actor can improve performance. In some cases, two sets of values are specified for access portions depending on their interconnection to the transit portion. One set of values applies when the access portion is nominally interconnected to the transit portion. The other set applies when the access an
19、d transit portion providers cooperatively plan the intercon-nection. These two sets of values are called nominal interconnection values and cooperatively planned in-terconnection values, respectively. An example of a cooperatively planned interconnection is one that re-duces the number of switches b
20、etween the NI and the INI. The organization of this standard is summarized in figure 2. Clause 2 identifies the normative references. Clause 3 defines an ISDN performance model that (a) specifies the boundaries and connection portion types and (b) defines a set of protocol-specific reference events
21、that provide a basis for performance parameter definition. Clauses 4 and 5 provide a basis for performance assessment of ISDN circuit mode bearer ser-vices and packet mode bearer services, respectively. These clauses define protocol-specific performance parameters and specify worst-case performance
22、objectives. Annex A provides a bibliography. ATIS-0100517.1995 4 Clause4CIRCUIT-MODEPARAMETERDEFINITIONSWORST-CASE OBJECTIVESClause5PACKET-MODEClause3REFERENCEMODELBOUNDARIESPORTIONSREFERENCEEVENTSClause2NORMATIVESTANDARDSClause1PURPOSEandSCOPEFigure 2 - Organization of T1.5IPARAMETERDEFINITIONSWORS
23、T-CASE OBJECTIVESGLOSSARYOF ACRONYMSBIBLIOGRAPHYAnnexesFigure 2 Organization of ANSI T1.517-1995 ATIS-0100517.1995 5 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 publi
24、cation, 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 T1.113-1995, Telecommunicatio
25、ns Signalling system no. 7 (SS7) Integrated services digital net-work (ISDN) user part ANSI T1.403-1995, Telecommunications Network-to-customer installation DS1 metallic interface ANSI T1.504-1989, Telecommunications Packet-switched data communication service Performance pa-rameters ANSI T1.504a-199
26、1, Telecommunications Packet-switched data communication service Performance measurement methods ANSI T1.504b-1993, Telecommunications Packet-switched data communication service Performance objectives ANSI T1.602-1989, Telecommunications Integrated services digital network (ISDN) Data-link layer sig
27、-nalling specification for application at the user-network interface ANSI T1.607-1990, Telecommunications Integrated services digital network (ISDN) Layer 3 signaling specification for circuit-switched bearer service for digital subscriber signaling system number 1 (DSS1) ANSI T1.608-1991, Telecommu
28、nications Integrated services digital network (ISDN) Signaling specifica-tion for X.25 Packet-switched bearer service for digital subscriber signaling system number 1 (DSS1) ANSI T1.608a-1992, Telecommunications Integrated services digital network (ISDN) Signaling specifica-tion for X.25 Packet-swit
29、ched bearer service for digital subscriber signaling system number 1 (DSS1) (Ter-minal initialization procedures for packet mode data) Part of ANSI T1.608-1991 ANSI T1.614-1991, Telecommunications Integrated services digital network (ISDN) Packet mode bearer service category description 3 Performanc
30、e model This clause of the standard defines an ISDN performance model that provides a basis for ISDN performance parameter definition. The ISDN performance model comprises an ISDN reference configuration, jurisdic-tional boundaries, and associated access and transit connection portions, and a set of
31、 performance-significant reference events (see figure 3). To facilitate parameter definition, the connection portions are subdivided into network fabrics and links. A representative end-to-end national ISDN connection consists of two access portions and an intervening transit portion. Although other
32、 jurisdictional arrangements are possi-ble, an access portion is generally comprised of facilities provided by an “exchange carrier“ and a transit por-tion is generally comprised of facilities provided by an “inter-exchange carrier.“ Worst-case performance objectives are specified for the access and
33、 transit portions. Direct measurement of performance at the defined jurisdictional boundaries will not always be practical. This standard defines functional boundaries that may serve as practical surrogates for the jurisdictional bounda-ries. The standard establishes guidelines for estimating the pe
34、rformance of jurisdictional portions on the ba-sis of measurements taken at the functional boundaries. ATIS-0100517.1995 6 INI INIANFAL ALNI NIBBAAT* T*LEGENDNIINITLAL= NetworkInterface= InternetworkInterface= TransitLink= AccessLinkANFTNFT, A, B= AccessNetworkFabric= TransitNetworkFabric= Functiona
35、lBoundariesConnectionPortionsJurisdictionalBoundariesISDNPerformanceReferenceConfigurationFunctionalBoundariesTNF ANFNOTE - * ReferencepointT maybe coincidentwiththeNIor maybe createdat theNI by an attachedNT1Figure 3 - Provisional national ISDN performance allocation modelACCESSPORTIONACCESSPORTION
36、TRANSITPORTIONTL TLFigure 3 Provisional national ISDN performance allocation model ATIS-0100517.1995 7 3.1 Definitions In the context of this standard, the following definitions apply: 3.1.1 network interface (NI): The NI is the jurisdictional boundary between the customers installation and the netw
37、ork providers equipment. This standard uses the NI boundaries to allocate ISDN performance responsibilities between the customers and the network service providers. The ISDN T reference point, which separates the NT1 and TE (or NT2) functions is considered coincident with the NI for measurement purp
38、oses (see 3.2). 3.1.2 internetwork interface (INI): The INI is the jurisdictional boundary between the access network providers and transit network providers equipment. This standard uses the INI boundaries to allocate ISDN performance responsibilities among the access network and transit network se
39、rvice providers. 3.1.3 access portion: The access portion is the portion of an end-to-end ISDN connection between a network interface and the closest internetwork interface. An access portion carries user information and sig-naling information between the network and internetwork interfaces. An acce
40、ss portion typically includes an access link and an access network fabric. 3.1.4 transit portion: The transit portion is the portion of an end-to-end ISDN connection between the two internetwork interfaces. The transit portion carries user information and signaling information between the two INIs.
41、A transit portion normally includes a transit network fabric. 3.1.5 access link (AL): An AL is a physical circuit or set of circuits connecting an NI to a switching func-tion. An AL transports user information and signaling information. 3.1.6 transit link (TL): A TL is a physical circuit or set of c
42、ircuits connecting a switching function or sig-naling node in one jurisdiction with a switching function or signaling node in another jurisdiction. 3.1.6.1 transit link access component: That component of the TL within the access portion. 3.1.6.2 transit link transit component: That component of the
43、 TL within the transit portion. 3.1.7 access network fabric (ANF): An ANF consists of network components that route user information and signaling information between an access link and one or more transit links. 3.1.8 transit network fabric (TNF): The TNF consists of the network components that rou
44、te user infor-mation and signaling information between two sets of transit links. 3.1.9 functional boundaries (T, A, B): The functional boundaries, (denoted T, A, and B) represent loca-tions in the ISDN reference configuration where practical performance measurements can be made. The functional boun
45、dary T refers to the ISDN T reference point (see clause 2 and annex A) that separates the NT1 and TE (or NT2) functions. The functional boundaries A and B refer to the network locations where the transit link is terminated (e.g., switch locations). There are two functional boundaries associated with
46、 a ju-risdictional INI. 3.1.9.1 associated upstream functional boundary: The associated upstream functional boundary is the functional boundary nearest the INI from which the relevant function request is emanating. 3.1.9.2 associated downstream functional boundary: The associated downstream function
47、al bound-ary is the functional boundary nearest the INI toward which the relevant function request is destined. ATIS-0100517.1995 8 3.1.10 Acronyms AL Access link ANF Access network fabric ANSI American National Standards Institute CEP Connection set-up error probability CFP Connection set-up failur
48、e probability ES Errored second FFS For further study I Information INI Internetwork interface ISDN Integrated Services Digital Network ITU-T International Telecommunication Union-Telecommunication Standardization Sector LAPB Link access protocol balanced LAPD Link access protocol D-channel MTBSO Me
49、an time between service outages MTTSR Mean time to service restoral NE Network element NI Network interface NT Network termination PD Premature disconnect PDEP Premature disconnect event probability PDS Premature disconnect stimulus PDSP Premature disconnect stimulus probability PH Packet handler PSTN Public switched telephone network RE Reference event SA Service availability SABME Set asynchronous balanced mode extended SES Severely errored second SF Switching function SN Switching node SS7 Signaling System 7 T ISDN T
