1、ANSI INCITS 228-1993 (R2003)(formerly ANSI X3.228-1993 (R1998) for Information Systems X.25 Data Transfer Phase (DTP) Proceduresfor Operation with Frame RelayAmerican National StandardANSI X3.228-1993for information systems X.25 data transfer phase (DTP) proceduresfor operation with frame relayAppro
2、ved August 18, 1993 Secretariat: Computer and Business Equipment Manufacturers AssociationAn American National Standard implies a consensus of those substantially concerned with its scope and provisions. An AmericanNational Standard is intended as a guide to aid the manufacturer, the consumer, and t
3、he general public. The existence of anAmerican National Standard does not in any respect preclude anyone, whether he has approved the standard or not, from manufac-turing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. American NationalStandards ar
4、e subject to periodic review and users are cautioned to obtain the latest editions.The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of anyAmerican National Standard. Moreover, no person shall have the right or authority to issue
5、 an interpretation of an American NationalStandard in the name of the American National Standards Institute.CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the AmericanNational Standards Institute require that action be taken to reaffirm, re
6、vise, or withdraw this standard no later than five years from thedate of approval. Purchasers of American National Standards may receive current information on all standards by calling or writingthe American National Standards Institute.Foreword (This foreword is not part of AmericanNational Standar
7、d X3.228-1993.)Frame relay is an ISDN packet-mode bearer ser-vice with logically separate C-plane and U-planeinformation, as set forth in American NationalStandard for Telecommunications Integratedservices digital network (ISDN) Architecturalframework and service description for frame-relaying beare
8、r service, ANSI T1.606-1990. Thebasic frame relay bearer service provided by thenetwork is the order-preserving transfer of framesfrom the network side of one UserNetworkInterface (UNI) to the network side of the otherUNI. This basic bearer service must be enhancedby additional end-system functional
9、ity at the userside of the UNI to support the OSI NetworkService (OSI NS). Two types of NS have beendefined: a Connection-mode Network Service(CONS) and Connectionless-mode NetworkService (CLNS).CONS provides for data transfer through athree-phase process: first, an association (i.e.,Network Connect
10、ion) is established betweenthe Transport Layer entities that need to com-municate; data are then transferred; and final-ly, the Network Connection is released. AnnexC of American National Standard for Telecom-munications Integrated services digital net-work (ISDN) Signaling specification forframe re
11、lay bearer service for digital sub-scriber signaling system number 1 (DSS1),ANSI T1.617-1991 provides the mappingbetween the CONS primitives/parameters andthe corresponding messages/information ele-ments of the signaling protocol set forth inISDN usernetwork interface layer 3 specifica-tion for basi
12、c call control, CCITT Recom-mendation Q.931, for the connection estab-lishment and release phases. This standard isrelevant to supporting the data transfer phase(DTP) of the CONS.Two Network Layer (NL) protocols for providingthe CONS DTP over a frame relay bearer ser-vice have been identified. The f
13、irst is the X.25DTP protocol. The second is a simplified NLprotocol defined in Appendix IV of ISDN datalink layer specification for frame mode bearerservices, CCITT Recommendation Q.922.Page 1 of 6 pagesANSI X3.228-1993Copyright 1994 by Information Technology Industry Council (ITI). All rights reser
14、ved.These materials are subject to copyright claims of International Standardization Organization (ISO), American National Standards Institute (ANSI), and Information Technology Industry Council (ITI).Not for resale. No part of this publication may be reproduced in any form, including an electronic
15、retrieval system, without the prior written permission of ITI. All requests pertaining to this standardshould be submitted to ITI, 1250 Eye Street NW, Washington, DC 20005.Copyright 1994 by Information Technology Industry Council (ITI). All rights reserved.No part of this publication may be reproduc
16、ed in any form, in an electronic retrieval system or otherwise, without prior written permission of ITI, 1250 Eye Street NW,Washington, DC 20005.1 ScopeThe scope of this standard is two-fold. Theprotocol described in this standard, i.e., X.25Data Transfer Phase (DTP), facilitates:a) interworking wit
17、h X.25/X.31 subnet-works;b) provision of the data-transfer aspects ofthe OSI CONS in the frame relay end points(terminals).This standard is a subset of CCITTRecommendation X.25, ISO/IEC 8208, andISO 8878 and contains only those aspectsrelating to data transfer procedures. In addi-tion, this standard
18、 is consistent with ANSIX3.100-1989.Figures 1 and 2 show a set of D- and B-Channel protocol stacks for support by theframe relay terminals. In Figure 1, it isassumed that the B-Channel has been con-nected to the frame handler (either throughstatic provisioning or with the use of proce-dures on the D
19、-Channel, as described in ANSIT1.617). (When LAPB (ISO 7776) is used inthe figures, only the Address, Control, andInformation fields are used.)2 Normative referencesThe following standards contain provisionswhich, through reference in this text, consti-tute provisions of this American NationalStanda
20、rd. At the time of publication, the edi-tions indicated were valid. All standards aresubject to revision, and parties to agreementsbased on this American National Standard areencouraged to investigate the possibility ofapplying the most recent editions of the stan-dards indicated below.ANSI T1.602-1
21、989, Telecommunications Integrated services digital network (ISDN) Data-link layer signalling specification forapplication at the usernetwork interfaceANSI T1.606-1990, Telecommunications Integrated services digital network (ISDN) Architectural framework and service descrip-tion for frame-relaying b
22、earer serviceANSI T1.617-1991, Telecommunications Integrated services digital network (ISDN) This standard specifies how the CONS DTPcan be provided by the X.25 DTP protocol asan NL DTP protocol in the frame relay termi-nal equipment connected to a network sup-porting the frame relay bearer service.
23、 ThisLayer-3 X.25 DTP protocol is specified in amanner that enables:a) interworking with X.25/X.31 subnetworks;b) provision of OSI CONS in the framerelay end points (terminals).NOTE The use of the X.25 DTP, as definedhere, assumes the use of ANSI T1.617 for con-nection establishment and release. If
24、ANSIT1.617 is not used in this fashion (i.e., a semi-per-manent connection has has been preestab-lished), then other solutions need to be defined.In frame relaying, the communication isbetween two Terminal Equipments (TEs). Onthe transmitting side, the packet layer in asending TE performs the basic
25、function ofpacketizing messages delivered by a higher-layer entity in the same TE before giving theinformation to the data link layer protocol fortransmission. On the receiving side, the pack-et layer in a TE performs the basic functionsof receiving packets from the data link layer,checking packets
26、for correctness, stripping offpacket layer headers, and formulating mes-sages from the packetized user data andpassing them to a higher-layer entity. TheX.25 DTP protocol provides the followingfunctional capabilities that facilitate reliableand efficient data communications:a) data transfer;b) flow
27、control;c) interrupt transfer;d) error control;e) reset.These functions are made possible throughthe use of: data packets; send and receive sequence numbers; control packets that regulate informa-tion flow; interrupt packets; control packets that reinitialize commu-nications.Page 2 of 6 pagesANSI X3
28、.228-1993Page 3 of 6 pagesSignaling specification for frame relay bearerservice for digital subscriber signaling systemnumber 1 (DSS1)ANSI T1.618-1991, Telecommunications Integrated services digital network (ISDN) Core aspects of frame protocol for use withframe relay bearer serviceANSI X3.100-1989,
29、 Information systems Interface between data terminal equipment(DTE) and data circuit-terminating equipment(DCE) for operation with packet-switched datanetworks (PSDN), or between two DTEs, bydedicated circuitCCITT Recommendation I.320, ISDN protocolreference model1)CCITT Recommendation Q.921, ISDN u
30、sernetwork interface data link layer specification1)CCITT Recommendation Q.922, ISDN datalink layer specification for frame mode bearerservices1)CCITT Recommendation Q.931, ISDN usernetwork interface layer 3 specification forbasic call control1)CCITT Recommendation Q.933, DSS1 Signaling specificatio
31、n for frame mode bearerservice1)CCITT Recommendation X.25, Interfacebetween data terminal equipment (DTE) anddata circuit-terminating equipment (DCE) forterminals operating in the packet mode andconnected to public data networks by dedicat-ed circuit1)CCITT Recommendation X.31, Support ofpacket mode
32、 terminal equipment by ISDN1)ISO 7776:1986, Information processing sys-tems Data communications High-leveldata link control procedures Description ofthe X.25 LAPB-compatible DTE data link pro-cedures2)ISO 8878:1987, Information processing sys-tems Data communications Use of X.25 toprovide the OSI co
33、nnection-mode networkservice2)ISO/IEC 8208:1990, Information technology Data communications X.25 packet layer pro-tocol for data terminal equipment2)3 Requirements3.1 Packet layerThe provisions of ISO/IEC 8208 and ISO 8878dealing with the packet layer DTP proceduresshall be used with the following e
34、xceptions:a) Any reference to connection establish-ment and release phases does not apply,except for use of the release procedures asa result of an error in the data transferphase, since the out-of-band signaling callcontrol procedures described in CCITTRecommendations Q.931 and Q.933 areused for vi
35、rtual circuit establishment andclearing of the network connection;b) Any reference to multiplexing of logicalchannels does not apply;c) Any use of Reject, Registration, andRestart packets does not apply;d) Any use of X.25 optional facilities doesnot apply (however, the functional capabili-ties of so
36、me X.25 optional facilities, such asWindow Size Negotiation, are availablethrough ANSI T1.617).It is to be noted that since multiplexing of logi-cal channels is not within the scope of thisstandard, logical channel 1 is used (except forDiagnostic packets, which are carried on logi-cal channel 0).3.2
37、 List of relevant ISO/IEC 8208 clauses,tables, and figures3.2.1 ISO/IEC 8208 Clause 3, General con-siderations 3.8, 3.9, and 3.10; Table 1; Figure 2.ANSI X3.228-19931)The CCITT Recommendations listed in this standard appeared in the 1988 Blue Book. All CCITTRecommendations are available from the Ame
38、rican National Standards Institute, 11 West 42nd Street, NewYork, NY 10036.2)Available from the American National Standards Institute, 11 West 42nd Street, New York, NY 10036.3.2.9 ISO/IEC 8208 Clause 18, Timers andretransmission counts All of clause 18; Tables 26 through 28.3.2.10 ISO/IEC 8208 Clau
39、se 19, State dia-grams All of clause 19; Table 29; Figures 33, 34, and 35.3.2.11 ISO/IEC 8208 Clause 20, State tables All of clause 20; Tables 30, 31, and 34 through 36.3.3 List of relevant ISO 8878 clauses,tables, and figures3.3.1 ISO 8878 Clause 5, Overview All of clause 5; Table 1; Figure 2.3.3.2
40、 ISO 8878 Clause 8, Data transfer phase Data transfer service All of clause 8; Table 5.3.3.3 ISO 8878 Clause 9, Data transfer phase Receipt confirmation service All of clause 9;3.3.4 ISO 8878 Clause 10, Data transfer phase Expedited data transfer service All of clause 10; Table 6.3.3.5 ISO 8878 Clau
41、se 11, Data transferphase Reset service All of clause 11; Table 7.3.2.2 ISO/IEC 8208 Clause 6, Proceduresfor data and interrupt transfer All of clause 6; Table 2; Figures 6 and 7.3.2.3 ISO/IEC 8208 Clause 7, Proceduresfor flow control All of clause 7; Figure 8.NOTE It is recommended that a nonstanda
42、rddefault window size greater than 2 be agreedupon by the two TEs. Alternatively, proceduresset forth in CCITT Recommendation Q.933 can beused to negotiate a window size different from theISO/IEC 8208 default of 2.3.2.4 ISO/IEC 8208 Clause 8, Proceduresfor reset All of clause 8; Figure 9.3.2.5 ISO/I
43、EC 8208 Clause 9, Effects ofprocedures on the transfer of packets All of clause 9.3.2.6 ISO/IEC 8208 Clause 11, Error handling All of clause 11.3.2.7 ISO/IEC 8208 Clause 12, Packet formats Clause 12: 12.1 through 12.1.3; 12.3 through 12.5.2; 12.7 through 12.7.2; Tables 3, 4, and 6; Figures 10, 15 th
44、rough 21, and 24.3.2.8 ISO/IEC 8208 Clause 17, Diagnosticcodes All of clause 17; Tables 24 and 25.Page 4 of 6 pagesANSI X3.228-1993ANSI X3.228-1993Page 5 of 6 pagesCORE (Note 3)Q.933 (Note 1)LAPFCORE (Note 3)X.25 DTPLAPB (ISO 7776)or LAPFCoordinating Function(Note 2)Data LinkLayer ServicePhysicalSam
45、e B-ChannelNOTES1 The equivalent American National Standard is ANSI T1.617.2 The Coordinating Function is a part of the global Synchronization and Coordinating Function (SCF),which is responsible for coordination of the two protocol stacks across the bottom layers. (The SCF is alsoresponsible for co
46、ordinating the operation of the bottom three layers with upper layer protocols. See CCITTRecommendation I.320.)3 The American National Standard that describes the CORE is ANSI T1.618. (The corresponding materialis in CCITT Recommendation Q.922.)Figure 1 Protocol stacks for case A in frame relay end
47、pointsANSI X3.228-1993Page 6 of 6 pagesNOTES1 The equivalent American National Standard is ANSI T1.617.2 The Coordinating Function is a part of a global Synchronization and Coordination Function (SCF), whichis responsible for coordination of the two protocols across the bottom layers. (The SCF is al
48、so responsiblefor coordinating the operation of the bottom three layers with upper layer protocols. See CCITTRecommendation I.320.)3 The equivalent American National Standard is ANSI T1.602. (The corresponding material is in CCITTRecommendation Q.921.)4 The equivalent American National Standard is ANSI T1.618. (The corresponding material is in CCITTRecommendation Q.922.)Figure 2 Protocol stacks for case B in frame relay end pointsCORE (Note 4)Q.933 (Note 1)LAPB(Note 3)CORE (Note 4)X.25 DTPLAPB (ISO 7776)or LAPFCoordinating Function(Note 2)Data LinkLayer ServicePhysicalD-Channel B-Channel
