1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0100513.2003(R2013) Frame Relay Data Communication Service -Access, User Information Transfer, Disengagement, and Availability Performance Parameters As a leading technology and solutions development organization, ATIS brings together the top g
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11、 National Standards Institute. Notice of Disclaimer (2) by equipment manufacturers as performance metrics that will affect equipment design; and (3) by users in evaluating performance. The scope of this standard is summarized in Figure 1. The frame relay performance parameters are defined on the bas
12、is of frame transfer reference events that may be observed at physical interfaces associated with specified boundaries. For comparability and completeness, frame relay performance is considered in the context of the 3x3 performance matrix defined in ANSI X3.102-1992. Three protocol-independent data
13、communication functions are identified in the matrix: (1) access, (2) user information transfer, and (3) disengagement. Each function is considered with respect to three general performance concerns (or “performance criteria“): speed, accuracy, and dependability. An associated two-state model provid
14、es a basis for describing permanent virtual circuit (PVC) service availability. The performance parameters defined in this standard describe the speed, accuracy, dependability, and availability of frame relay networks. - 1In the context of this standard, a frame relay connection (denoted hereafter,
15、unless noted otherwise, by the term connection) refers to a virtual connection established between two specified end points. ATIS-0100513.2003 2 Figure 1 - Scope of T1.513-2003 ATIS-0100513.2003 3 NOTES 0 The parameters defined in this standard may be augmented or modified based upon further study o
16、f the requirements of the services to be supported on frame relay networks. 0 The speed, accuracy, and dependability parameters are intended to characterize frame relay connections in the available state. 0 The parameters of this standard are designed to measure the performance of network elements b
17、etween two section boundaries. However, users of this standard should be aware that the behavior of connection elements outside the pair of boundaries can negatively influence the measured performance of the elements between the boundaries. Examples are described in Annex F. This standard is organiz
18、ed as follows: Clause 2 presents the normative references; Clause 3 defines a performance model and a set of frame transfer reference events (FEs) that provide a basis for performance parameter definition; Clause 4 defines frame-based speed of service, accuracy, and dependability parameters for the
19、information transfer phase using the FEs defined in clause 3; Clause 5 defines quality of services classes for the information transfer phase; Clause 6 provides allocation rules for the objectives of the classes of clause 5; Clause 7 defines frame-based speed of service, accuracy, and dependability
20、parameters for the access and disengagement phases using the FEs defined in clause 3; Clause 8 defines the PVC availability parameters using the primary parameters defined in clause 4; Annex A presents a test for judging traffic conformance for performance assessment purposes; Annex B defines bit-ba
21、sed accuracy and dependability parameters associated with the transfer of user information in frame relay services; Annex C provides a glossary of acronyms; Annex D provides information on sampling estimation of the PVC availability parameters; Annex E discusses the performance effects of network in
22、dications of congestion and makes general recommendations for controlling these effects; Annex F identifies effects of external connection elements on measured performance; Annex G presents relationships between Frame Relay and ATM performance for Frame Relay PVCs supported by an ATM network; and An
23、nex H is the Bibliography. 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 publication, the editions indicated were valid. All standards are subject to revision, and part
24、ies 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. ATIS-0100513.2003 4 T1.511-2003, B-ISDN ATM layer cell transfer performance.2T1.606a-1992 (R1997), Integrated Services Digit
25、al Network (ISDN) Architectural framework and service description for frame-relaying bearer service (congestion management and frame size) Supplement to T1.606-1990 (R1996).2T1.617-1991 (R1997), Integrated Services Digital Network (ISDN) Signaling specification for frame relay bearer service for Dig
26、ital Subscriber Signaling System Number 1 (DSS1).2T1.617a-1994, Integrated Services Digital Network (ISDN) Signaling specification for frame relay bearer service for Digital Subscriber Signaling System Number 1 (DSS1) (Protocol Encapsulation and PICS) Supplement to T1.617-1991 (R1997).2T1.618-1991 (
27、R2003), Integrated Services Digital Network (ISDN) Core aspects of frame protocol for use with frame relay bearer service.2T1.634-1993 (R2001), Frame relaying service specific convergence sublayer (FR-SSCS).2ITU-T Recommendation I.363 (03/93), B-ISDN ATM adaptation layer specification.3ITU-T Recomme
28、ndation X.36 (04/95), Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for public data networks providing frame relay data transmission service by dedicated circuit.3ITU-T Recommendation X.76 (04/95), Network-to-network interface between public data networ
29、ks providing frame relay data transmission service.3 3 Generic Performance Model This clause defines a generic frame relay service performance model composed of four basic connection sections: 1) the access circuit section; 2) the internetwork circuit section; 3) the access network section; and 4) t
30、he transit network section. These four basic connection sections are defined in 3.1. They provide a set of building blocks with which any end-to-end connection can be represented. Each of the performance parameters defined herein can be applied to the unidirectional transfer of user information on a
31、 connection section or a concatenated set of connection sections. This clause also specifies a set of frame transfer reference events that provide a basis for performance parameter definition. These reference events are derived from and are consistent with relevant ANSI frame relay service and proto
32、col standards. The reference events are specified in 3.2. NOTE A planned supplement to T1.513-2003 for specification of design objectives (see clause 1) will adapt the generic performance model defined in this clause to provide a jurisdictional basis for the specification and apportionment of frame
33、relay user information transfer performance. The generic model defined in this clause partitions an end-to-end connection into basic sections and defines a set of performance-significant reference events that may be observed at the section boundaries. The performance specification model will add jur
34、isdictional boundaries, define associated access and transit connection portions, and adapt the generic reference event definitions for application at the jurisdictional boundaries. Direct measurement of performance at the defined jursidictional boundaries will not always be practical. Section bound
35、aries (defined in 3.1) may serve as practical surrogates for the jurisdictional boundaries in many cases. - 2This document is available from the Alliance for Telecommunications Industry Solutions, 1200 G Street N.W., Suite 500, Washington, DC 20005. 3This document is available from the International
36、 Telecommunications Union. ATIS-0100513.2003 5 This document provides parameters for quantifying performance at the top of the data link (i.e., frame) layer service access point (SAP). Quantitative relationships between frame layer network performance and the performance of layers below and above th
37、e frame layer are for further study. 3.1 Components of an end-to-end connection In the context of this standard, an end-to-end connection is composed of sections as defined below. The defined terms are shown in Figure 2. 3.1.1 circuit section: Either an access circuit section or an internetwork circ
38、uit section. 3.1.1.1 access circuit section (ACS): The physical circuit or set of circuits connecting a Data Terminal Equipment (DTE)4to the (local) Data Switching Exchange (DSE). It does not include any parts of the DTE or DSE. 3.1.1.2 internetwork circuit section (ICS): The physical circuit or set
39、 of circuits connecting a DSE in one network with a DSE in a different network. It does not include any parts of either DSE. 3.1.2 network section: The network components that provide the connection between two circuit sections. A network section may be either an access network section or a transit
40、network section. 3.1.2.1 access network section (ANS): A network section connected to (at least) one access circuit section. 3.1.2.2 transit network section (TNS): A network section between two internetwork circuit sections. 3.1.3 basic section of a connection: A general term for an access circuit s
41、ection, an internetwork circuit section, an access network section, or a transit network section. 3.1.4 section boundary: The boundary that separates a network section from the adjacent circuit section, or separates an access circuit section from the adjacent DTE. (Also called boundary.) Figure 2 -
42、Sections of a national virtual connection - 4In the context of this standard, routers are considered as DTE. ATIS-0100513.2003 6 Figure 3 - Example frame transfer reference events 3.2 Frame transfer reference events In the context of this standard, the following definitions apply on a specified conn
43、ection. The defined terms are illustrated in Figure 3. 3.2.1 Frame transfer reference event: The event that occurs when all of three of the following conditions occur: ) A frame crosses a section boundary; ) The frame is identified as a user information frame; and ) The DLCI field indicates that the
44、 frame belongs to this connection. Frame transfer reference events can be observed at the physical boundaries terminating a circuit section. Two classes of frame transfer reference events are defined: 3.2.1.1 frame entry event: A frame transfer reference event that corresponds to a frame entering a
45、network section (from a circuit section) or a frame entering a DTE (from an access circuit section). The time of occurrence of a frame transfer entry event is defined to coincide with the time at which the last bit of the closing flag of the frame crosses the boundary into the network section or DTE
46、. 3.2.1.2 frame exit event: A frame transfer reference event that corresponds to a frame exiting a network section (to a circuit section) or a frame exiting a DTE (to an access circuit section). The time of occurrence of a frame transfer exit event is defined to coincide with the time at which the f
47、irst bit of the address field of the frame crosses the boundary out of the network section or DTE. ATIS-0100513.2003 7 Figure 4 - Frame transfer outcomes ATIS-0100513.2003 8 3.3 Frame transfer outcomes In the following, it is assumed that the sequence of frames on a connection is preserved. Two even
48、ts on a connection are said to be corresponding if they can be related to the same source frame. By considering two frame transfer reference events - FE1and FE2at Biand Bj,5respectively - four basic frame transfer outcomes may be defined. A transmitted frame is either successfully transferred, lost,
49、 or residually errored. A received frame for which no corresponding transmitted frame exists is said to be extra. Extra frames can occur as a result of errors in the address of a frame from a different connection.6Figure 4 illustrates the four basic frame transfer outcome definitions. 3.3.1 Successful frame transfer outcome A successful frame transfer outcome occurs when an FE2corresponding to FE1happens within a specified time Tmaxafter FE1, and: (a) the Cyclical Redundancy Check (CRC) of the received frame is valid; and (b) the
