1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Q.933TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2003) SERIES Q: SWITCHING AND SIGNALLING Digital subscriber Signalling System No. 1 Network layerISDN Digital Subscriber Signalling System No. 1 (DSS1) Signalling specifications for frame mode switc
2、hed and permanent virtual connection control and status monitoring ITU-T Recommendation Q.933 ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR S
3、ERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEM No. 4 Q.120Q.139 SPECIFICATIONS OF SIGNALLING SYSTEM No. 5 Q.140Q.199 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309 SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399 SPECIF
4、ICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 General Q.850Q.919 Data link layer Q.920Q.929 Netw
5、ork layer Q.930Q.939 User-network management Q.940Q.949 Stage 3 description for supplementary services using DSS1 Q.950Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-
6、2000 Q.1700Q.1799 SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. Q.933 (02/2003) i ITU-T Recommendation Q.933 ISDN Digital Subscriber Signalling
7、 System No. 1 (DSS1) Signalling specifications for frame mode switched and permanent virtual connection control and status monitoring Summary This Recommendation defines the access to Remote Frame Handlers from ISDN user-network interfaces. It specifies the signalling to establish, maintain and rele
8、ase circuit-switched bearers between ISDN users and Remote Frame Handlers mainly by referencing ITU-T Rec. Q.931. It specifies also the signalling to establish, maintain and release frame relay virtual circuits within an established circuit-switched bearer by referencing ITU-T Rec. X.36. In addition
9、, it includes the protocol for frame relay permanent virtual connection status monitoring, together with the corresponding Protocol Implementation Conformance Statements (PICS) proforma. This revision replaces ITU-T Rec. Q.933 (1995) and no longer supports case B of Q.933 (1995) whereby ISDN local e
10、xchanges provide frame relay services. This revision of ITU-T Rec. Q.933 (2003) is in alignment with the latest release of ITU-T Recs X.76 (2003) and X.36 (2003). Source ITU-T Recommendation Q.933 was revised by ITU-T Study Group 17 (2001-2004) and approved under the WTSA Resolution 1 procedure on 1
11、3 February 2003. ii ITU-T Rec. Q.933 (02/2003) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying
12、 technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups w
13、hich, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO a
14、nd IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommen
15、dation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approv
16、al of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB pa
17、tent database. ITU 2003 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. Q.933 (02/2003) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbreviations 2 5 Conventions 2 6 Overview of ISD
18、N access to a Remote Frame Handler . 3 7 Frame relay call control procedures . 3 7.1 Outgoing call 3 7.2 Incoming call 4 7.3 Frame relay data transfer phase protocol 5 7.4 Call clearing 5 7.5 Restart procedures 5 7.6 Handling of error conditions 5 7.7 Timers. 5 Annex A Additional procedures for Perm
19、anent Virtual Connection (PVC) status management (using Unnumbered Information frames) 6 A.1 Messages used for PVC status 6 A.2 Information elements 7 A.3 Information elements 8 A.4 Procedures 9 A.5 Error conditions 12 A.6 Optional bidirectional network procedures 13 A.7 System parameters 15 A.8 Ann
20、ex A SDL specification 15 Annex B Additional procedures for permanent frame relay connection using acknowledged mode of operation. 30 Annex C Provision of OSI connection mode network services (NC-establishment and release phases) 30 Annex D PICS proforma for Annex A 30 D.1 Introduction 30 D.2 Identi
21、fication of the implementation 32 D.3 Identification of the protocol 34 D.4 Global statement of conformance. 34 D.5 Procedures for frame relay PVC management . 34 Annex E Multiprotocol encapsulation over frame relay. 37 Appendix I Window size for a data link layer protocol 37 ITU-T Rec. Q.933 (02/20
22、03) 1 ITU-T Recommendation Q.933 ISDN Digital Subscriber Signalling System No. 1 (DSS1) Signalling specifications for frame mode switched and permanent virtual connection control and status monitoring 1 Scope This Recommendation specifies the architecture and the signalling using ITU-T Rec. Q.931 fo
23、r establishing, maintaining and clearing circuit-switched bearers at the ISDN user-network interface for both basic and primary rate interfaces to access a Remote Frame Handler. Within a circuit-switched bearer, one or more frame relay virtual circuits may be established. Establishing, maintaining a
24、nd clearing frame relay switched virtual circuits are performed using X.36 signalling. This Recommendation covers the following capabilities at the ISDN S/T reference point: 1) Circuit-switched access to a Remote Frame Handler (RFH) by establishing a circuit-switched bearer (ISDN B or H channels) be
25、tween a user and a RFH using the signalling defined in ITU-T Rec. Q.931. 2) Establishing, maintaining and releasing of frame mode virtual circuits within a circuit-mode bearer with the signalling defined in ITU-T Rec. X.36. Note that frame relay capabilities and services provided by a local ISDN exc
26、hange (ET) known as case B in the previous version of this Recommendation are not supported in this current version. To avoid duplicating the signalling protocols as specified in ITU-T Recs Q.931 and X.36, this Recommendation only makes references to them. Only the material unavailable elsewhere is
27、explicitly specified in this Recommendation. Clause 6 provides an overview of ISDN access to a Remote Frame Handler and clause 7 describes the call control procedures to establish, maintain and clear frame relay calls. Annex A provides the status reporting signalling for frame mode permanent virtual
28、 circuits and explains the relationship with clause 11/X.36. Annex D contains the PICS related to Annex A. Annexes B and C have been deleted and Annex E is replaced by Annex D/X.36. Appendix I moved to Appendix VII/X.36. 2 References The following ITU-T Recommendations and other references contain p
29、rovisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the pos
30、sibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recom
31、mendation. ITU-T Recommendation I.230 (1988), Definitions of bearer services categories. ITU-T Recommendation I.231.1 (1988), Circuit-mode bearer service categories: Circuit-mode 64 kbit/s unrestricted, 8 kHz structured bearer service. ITU-T Recommendation I.231.7 (1996), Circuit-mode bearer service
32、 categories: Circuit-mode 1536 kbit/s unrestricted, 8 kHz structured bearer service. ITU-T Recommendation I.231.8 (1996), Circuit-mode bearer service categories: Circuit-mode 1920 kbit/s unrestricted, 8 kHz structured bearer service. ITU-T Recommendation I.231.10 (1992), Circuit-mode bearer service
33、categories: Circuit-mode multiple-rate unrestricted 8 kHz structured bearer service. 2 ITU-T Rec. Q.933 (02/2003) ITU-T Recommendation I.320 (1993), ISDN protocol reference model. ITU-T Recommendation I.411 (1993), ISDN user-network interface Reference configurations. ITU-T Recommendation I.430 (199
34、5), Basic user-network interface Layer 1 specification. ITU-T Recommendation I.431 (1993), Primary rate user-network interface Layer 1 specification. ITU-T Recommendation Q.922 (1992), ISDN data link layer specification for frame mode bearer services. ITU-T Recommendation Q.931 (1998), ISDN user-net
35、work interface layer 3 specification for basic call control. ITU-T Recommendation X.36 (2003), 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. 3 Definitions No
36、new definitions that are specific to this Recommendation are defined. 4 Abbreviations This Recommendation uses the following abbreviations: DLCI Data Link Connection Identifier DTE Data Terminal Equipment ET Exchange Termination FR Frame Relay ISDN Integrated Services Digital Network ISO Internation
37、al Organization for Standardization LAPB Link Access Protocol Balanced NT2 Network Termination 2 PVC Permanent Virtual Circuit or Permanent Virtual Connection RFH Remote Frame Handler SABME Set Asynchronous Balanced Mode Extended (frame) SVC Switched Virtual Circuit or Switched Virtual Connection TA
38、 Terminal Adaptor TE1 Terminal Equipment 1 UA Unnumbered Acknowledgment XID Exchange Identification 5 Conventions No conventions specific to this Recommendation are defined. ITU-T Rec. Q.933 (02/2003) 3 6 Overview of ISDN access to a Remote Frame Handler The architecture of ISDN access to a Remote F
39、rame Handler (RFH) is illustrated in Figure 1. The user, shown as a TE1 or NT2, is located at the user side of an ISDN user-network interface and the Remote Frame Handler (RFH) is shown to be outside the ISDN for practical purposes. ITU-T Rec. Q.931 is used between the ISDN user and an ISDN local ex
40、change (ET) and between an ISDN exchange and the RFH to set up, maintain and release a circuit-switched bearer between the user and the RFH. If a semi-permanent bearer exists between the ISDN user and the RFH, then Q.931 signalling will not be used. Once a circuit-switched bearer has been establishe
41、d between a user and a RFH, one or more frame relay virtual circuits may be established within the circuit-switched bearer. ITU-T Rec. X.36 is used between an ISDN user and a RFH to establish, maintain and release a frame relay switched virtual circuit (SVC) with a remote FR DTE. Instead of SVC, fra
42、me relay permanent virtual circuits (PVC) between an ISDN user and a remote FR DTE may be used. Frame relay PVCs are established, maintained and released using network administrative mechanisms. Q.933_F01ET ET RFHS/TISDNNT2or TE1Frame relay networkFR DCEFR DTEFR UNI(X.36)Two-step signalling: Step 1:
43、 Circuit-switched bearer establishment between NT2/TE1 and the RFH using Q.931 signallingbetween NT2/TE1 and the local ET. Note this step is not required if a semi-permanent connection established with administrative means exists already between NT2/TE1 and the RFH. Step 2: Frame relay signalling be
44、tween NT2/TE1 and RFH using X.36 signalling to establish a framerelay virtual circuit between NT2/TE1 and the FR DTE. Multiple frame relay virtual circuits may beestablished within one bearer circuit between NT2/TE1 and the RFH.Figure 1/Q.933 Two-step frame mode call establishment 7 Frame relay call
45、 control procedures This clause describes the signalling procedures to support frame relay calls. It describes the two-step signalling process for the establishment of circuit-switched bearers and frame relay virtual circuits and for related call control functions. The user may access a RFH by means
46、 of a circuit-switched bearer (ISDN B or H channel). This circuit-switched bearer may be initiated by the user or the RFH. The term “user“ refers to the user equipment which may consist of an ISDN frame relay terminal (TE1), an ISDN NT2 or a combination of an existing data terminating equipment (TE2
47、) attached to a terminal adaptor (TA). 7.1 Outgoing call 7.1.1 Circuit-switched access to a Remote Frame Handler A circuit-switched bearer between the originating user and the RFH must be in place before the frame relay virtual circuits can be established. ITU-T Rec. Q.931 shall be used to establish
48、 this circuit-switched bearer. 4 ITU-T Rec. Q.933 (02/2003) Unless the circuit-switched bearer between the ISDN user and the RFH is a semi-permanent bearer, the originating user shall initiate the establishment of the circuit-switched bearer prior to establishing a frame relay virtual circuit. It do
49、es so by sending a SETUP message on the D-channel in which the Called party number information element is coded with the address of the RFH and the Bearer capability information element is coded with: information transfer capability set to “unrestricted digital information“; transfer mode set to “circuit mode“; and information transfer rate set to the bit rate of the bearer channel. The Low layer compatibility information element is optionally included in the SETUP message. Once establishment of the circui
