1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-1000618.1991(R2013) Integrated Services Digital Network (ISDN) Core Aspects of Frame Protocol for Use with Frame Relay Bearer Service As a leading technology and solutions development organization, ATIS brings together the top global ICT compan
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3、more. These priorities follow a fast-track development lifecycle from design and innovation through solutions that include standards, specifications, requirements, business use cases, software toolkits, and interoperability testing. ATIS is accredited by the American National Standards Institute (AN
4、SI). ATIS is the North American Organizational Partner for the 3rd Generation Partnership Project (3GPP), a founding Partner of oneM2M, a member and major U.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications sectors, and a member of the Inter-American Tele
5、communication Commission (CITEL). For more information, visit. AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is establi
6、shed when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be con
7、sidered, and that a concerted effort be made towards their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the standards or not, from manufacturing, marketing, purchasing, or using products,
8、processes, or procedures not conforming 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
9、 American National Standard in 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 CAUTION NOTICE: This American National Standard may be revised or withdrawn at a
10、ny time. The procedures of the 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 Standa
11、rds Institute. Notice of Disclaimer their existence does not in any respect preclude anyone, whether he has approvedthe standards or not, from manufacturing, marketing, purchasing, or usingproducts, processes, or procedures not conforming to the standards.The American National Standards Institute do
12、es not develop standards andwill in no circumstances give an interpretation of any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in the name of the AmericanNational Standards Institute. Requests for interpr
13、etations should be ad-dressed to the secretariat or sponsor whose name appears on the title pageof this standard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be taken periodicall
14、y to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards mayreceive current information on all standards by calling or writing the AmericanNational Standards Institute.Published byAmerican National Standards Institute11 West 42nd Street, New York, New York 10036Cop
15、yright 1992 by Exchange Carriers Standards AssociationAll rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of AmericaForeword ii1 Scope and purpose.1
16、2 Normative references .13 Definitions14 Frame relay frame structure35 Elements of procedures and format of fields for core services sublayer56 Placement of the DL-CORE protocol in the ISDN protocol architecture .87 Congestion control .98 Consolidated link layer management (CLLM) message 10Tables1 D
17、LCI values for B-channel and H-channel applications 72 DLCI values for D-channel 83 DL-CORE sublayer management primitives and parameters 8Figures1 Frame relay frame format with two-octet address .32 Format convention53 Field mapping conventions .54 FCS mapping conventions 55 Address field format66
18、A consolidated link layer management message (B- or H- channel)using a two-octet address field 117 A consolidated link layer management message (D- channel)using a two-octet address field 118 A consolidated link layer management message (B- or H- channel)using a three-octet address field149 A consol
19、idated link layer management message (D- channel)using a three-octet address field1410 A consolidated link layer management message (B- or H- channel)using a four-octet address field1511 A consolidated link layer management message (D- channel)using a four-octet address field15AnnexesA Sample algori
20、thms for using FECN and BECN .16B Bibliography .22ContentsPageiiiForeword (This foreword is not part of American National Standard T1.618-1991.)This standard and ANSI T1.617 were developed in parallel over a period of fiveyears within committee T1S1 and its predecessor committee T1D1. All work onthe
21、se standards has been done in close cooperation with parallel work in CCITT todevelop an extension to CCITT Recommendation Q.921 and a new CCITTRecommendation Q.922 that reflects the material contained in this document. Atthe time of publication this document is closely aligned with a stable draft C
22、CITTRecommendation for Q.922.Although the material in this standard is directed towards usage with high-qualityISDN services, a significant portion has application for use with any other digitallow-error-rate services. Usage with non-ISDN services is not clearly delineatedin the text and may be a su
23、bject for further standardization. The application ofthis standard to higher speed digital services is also a subject for future work.This standard contains two annexes for information only and they are designatedinformative.Suggestions for improvement of this standard will be welcome. They should b
24、esent to the Exchange Carriers Standards Association, 1200 G Street, NW, Suite500, Washington, DC 20005.This standard was processed and approved for submittal to ANSI by AccreditedStandards Committee on Telecommunications, T1. Committee approval of thisstandard does not necessarily imply that all co
25、mmittee members voted for itsapproval. At the time it approved this standard, Committee T1 had the followingmembers:Ivor N. Knight, ChairmanArthur K. Reilly, Vice-ChairmanO.J. Gusella, SecretaryOrganization Represented Name of RepresentativeEXCHANGE CARRIERSAmeritech Services, Inc .Laurence A. Young
26、Robert Koren (Alt)Bell Atlantic Corporation John W. SeazholtzRoger Nucho (Alt) Bellcore.G. Gary SchlangerRalph E. Jensen (Alt) BellSouth Services Leonard Strickland, JrWilliam J. McNamara III (Alt)Centel Corporation Bruce Becker Cincinnati Bell Telephone William P. KeidelT. C. Grimes (Alt)Contel Cor
27、poration Steve LinskeyStephen P. Welsh (Alt) Exchange Carriers Standards AssociationJoseph MendozaGregory L. Theus (Alt) GTE Telephone Operations .Gregory L. Theus Richard L. Cochran (Alt)National Telephone Cooperative Association .Joseph M. FlaniganNYNEX .Bencilla JenkinsLeo Katz (Alt) Pacific Bell
28、 Fred DoellStanley Chum (Alt)Puerto Rico Telephone Company.Segundo Ruiz Southern New England Telephone .H. D. Mulla J. K. Vij (Alt) Southwestern Bell Telephone Company .C. C. BaileyJoseph Mendoza (Alt.) iiiUnited States Telephone Association (USTA) Paul K. Hart Thomas Gajeski (Alt.)United Telecommun
29、ications, Inc Robert P. McCabe Harold L. Fuller (Alt.) U S West.James L. EitelJames Dahl (Alt.) INTEREXCHANGE CARRIERSAT frame multiplexing/demultiplexing usingthe address field; inspection of the frame to ensure that itconsists of an integer number of octets priorto zero bit insertion or following
30、zero bitextraction; inspection of the frame to ensure that it isnot too long or too short; detection of (but not recovery from)transmission errors; and congestion control functions.2 Normative referencesThe following standards contain provisionswhich, through reference in this text, constituteprovis
31、ions of this American National Standard.At the time of publication, the editions indicatedwere valid. All standards are subject to revi-sion, and parties to agreements based on thisAmerican National Standard are encouraged toinvestigate the possibility of applying the mostrecent editions of the stan
32、dards indicatedbelow.ANSI T1.602-1990, Telecommunications Integrated Services Digital Network (ISDN) Data link layer signaling specification forapplication at the usernetwork interfaceANSI T1.606-1989, Telecommunications Integrated Services Digital Network (ISDN) Architectural framework and service
33、descrip-tion for frame-relaying bearer service3 Definitions3.1 B-channel: A 64-kbit/s channel accom-panied by timing, intended to carry a wide vari-ety of user information streams, such as voiceencoded at 64 kbit/s, data information at bitrates less than or equal to 64 kbit/s, widebandvoice encoded
34、at 64 kbit/s, and voice encoded3.10 ISDN (Integrated Services DigitalNetwork): A network, in general evolving froman existing telephony network, which providesend-to-end digital connectivity to support awide range of both voice and nonvoice ser-vices. User access to an ISDN is via a limitedset of st
35、andard multipurpose interfaces.3.11 network or network side: The systemor equipment on one side of the ISDNusernetwork interface (basic rate or primaryrate) that provides a port through which theuser gains access to the telecommunicationservices offered by the ISDN.3.12 Network Termination 1 (NT1):
36、A func-tional group that includes functions broadlyequivalent to layer 1 (physical) of the OSI ref-erence model. These functions are associatedwith the proper physical and electromagnetictermination of the network, and include linetransmission termination layer 1, the mainte-nance functions, perform
37、ance monitoring, tim-ing, power transfer, layer 1 multiplexing, andinterface termination.3.13 Network Termination 2 (NT2): A func-tional group that includes functions broadlyequivalent to layer 1 and higher layers of theCCITT Recommendation X.200 referencemodel. PBXs, local area networks, and termi-
38、nal controllers are examples of equipment orcombinations of equipment that provide NT2functions. These functions include layer 2 andlayer 3 protocol handling, layer 2 and layer 3multiplexing, switching, concentration, mainte-nance functions, and interface termination.3.14 primary rate interface: An
39、ISDNusernetwork interface where the interfacestructure is composed of multiple B-channelsand one D-channel. The bit rate of the D-chan-nel in this structure is 64 kbit/s. When a 1544-kbit/s primary rate interface is provided, theinterface structure is 23B+D.3.15 reference point: A conceptual pointdi
40、viding functional groups in an ISDN accessarrangement. In a specific access arrange-ment, a reference point may correspond to aphysical interface between pieces of equip-ment, or there may not be any physical inter-face corresponding to the reference point.3.16 S reference point: The conceptual ref-
41、erence point dividing the TE1 and the NT2 in aparticular ISDN access arrangement.ANSI T1.618-19912at bit rates less than 64 kbit/s alone or com-bined with other digital information streams.3.2 basic rate interface: An ISDN usernet-work interface where the interface structure iscomposed of two B-chan
42、nels and one D-chan-nel, 2B+D. The bit rate of the D-channel in thisstructure is 16 kbit/s.3.3 bidirectional asymmetric: The condi-tion in which the information flow characteris-tics provided by the service are different in thetwo directions.3.4 bidirectional symmetric: The conditionin which the inf
43、ormation flow characteristicsprovided by the service are the same betweentwo (or more) reference points in the forwardand backward directions.3.5 CCITT (International Telegraph andTelephone Consultative Committee): TheCCITT is a permanent organization of theInternational Telecommunications Union (IT
44、U),a specialized agency of the United Nationssince 1948. As the oldest international treatyorganization, the ITU traces its formal begin-nings to 1865. The CCITT was founded in1954 for the purpose of promoting and ensur-ing the operation of international telecommuni-cations systems.3.6 D-channel: A
45、16- or 64-kbit/s channelcarrying control and signaling information and,optionally, packetized information and teleme-try.3.7 default: The term “default” implies thatthe value defined should be used in theabsence of any predefined assignment or percall negotiation of alternative values.3.8 functional
46、 group: Sets of functions thatmay be needed in ISDN user access arrange-ments. In a particular access arrangement,specific functions in a functional group may ormay not be present, and may be performed inone or more pieces of equipment.3.9 H-channel: A 384-, 1472-, or 1536-kbit/schannel (H0, H10, an
47、d H11respectively)accompanied by timing, intended to carry awide variety of user information streams, suchas fast facsimile, video, high-speed data, high-quality audio, information streams each atrates less than the respective H-channel bitrates that have been rate-adapted or multi-plexed together,
48、and packet-switched informa-tion.ANSI T1.618-19913.17 T reference point: The conceptual ref-erence point dividing the NT2 and the NT1 in aparticular ISDN access arrangement.3.18 Terminal Equipment (TE): A function-al group that includes functions broadlybelonging to layer 1 and higher layers of theC
49、CITT Recommendation X.200 referencemodel. Digital telephones, data terminal equip-ment, and integrated work stations are exam-ples of equipment (or combinations of equip-ment) that provide these functions. Thesefunctions include protocol handling, mainte-nance functions, interface functions, and con-nection functions to other equipment.3.19 U reference point: A conceptual refer-ence point on the network side of the NT1 in aparticular ISDN access arrangement.3.20 unidirectional: The condition in whichthe information flow of messages is providedonly in on
