1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Q.2767.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2000) SERIES Q: SWITCHING AND SIGNALLING Broadband ISDN B-ISDN application protocols for the network signalling Soft PVC Capability ITU-T Recommendation Q.2767.1 (Formerly CCITT Recommendation) I
2、TU-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 SERVICES IN THE ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICAT
3、IONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 Q.120Q.249 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 Q.250Q.309 SPECIFICATIONS OF SIGNALLING SYSTEM R1 Q.310Q.399 SPECIFICATIONS OF SIGNALLING SYSTEM R2 Q.400Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF
4、SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.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-2000 Q.1700Q
5、.1799 BROADBAND ISDN Q.2000Q.2999 General aspects Q.2000Q.2099 Signalling ATM adaptation layer (SAAL) Q.2100Q.2199 Signalling network protocols Q.2200Q.2299 Common aspects of B-ISDN application protocols for access signalling and network signalling and interworking Q.2600Q.2699 B-ISDN application pr
6、otocols for the network signalling Q.2700Q.2899 B-ISDN application protocols for access signalling Q.2900Q.2999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Q.2767.1 (06/2000) i ITU-T Recommendation Q.2767.1 Soft PVC Capability Summary This Recommendation utilizes th
7、e normal procedures of Broadband ISDN User Part (B-ISUP) protocol in order to support soft Permanent Virtual Connections (soft PVCs) between their endpoints. The endpoints are responsible for maintaining the end-to-end circuit by setting up a new switched connection in case the existing switched con
8、nection is released or fails. Two types of soft PVC are supported: soft Permanent Virtual Path Connection (PVPC) and soft Permanent Virtual Channel Connection (PVCC). This Recommendation contains the additional message and parameter coding, procedures, ASE descriptions and interworking mapping table
9、s for the support of soft PVCC and soft PVPC services. Source ITU-T Recommendation Q.2767.1 was revised by ITU-T Study Group 11 (1997-2000) and approved under the WTSC Resolution 1 procedure on 15 June 2000. ii ITU-T Q.2767.1 (06/2000) FOREWORD The International Telecommunication Union (ITU) is the
10、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 technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing tel
11、ecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by t
12、he procedure laid down in WTSC 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 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both
13、 a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evi
14、dence, 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 approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which
15、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 patent database. Ge3 ITU 2001 All rights reserved. No part of this publication may be reproduced or utilized in
16、 any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. ITU-T Q.2767.1 (06/2000) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions. 2 4 Abbreviations 2 5 B-ISDN user part messages and parameters. 2 5.1 Formats . 3 5.1
17、.1 Soft PVC called endpoint parameter 3 5.1.2 Soft PVC calling endpoint parameter 4 6 Application process procedures 5 6.1 Connection setup. 5 6.1.1 Calling endpoint exchange. 5 6.1.2 Intermediate national exchange . 6 6.1.3 Outgoing international exchange . 6 6.1.4 Intermediate international exchan
18、ge 6 6.1.5 Incoming international exchange . 6 6.1.6 Called endpoint exchange 6 6.2 Answer 7 6.2.1 Called endpoint exchange 7 6.2.2 Calling endpoint exchange. 7 6.2.3 Other types of exchanges 7 6.3 Unsuccessful connection setup. 7 6.3.1 Calling endpoint exchange. 7 6.3.2 Other type of exchanges 7 6.
19、4 Storage of call setup information 8 6.5 Release 8 6.5.1 Release within the network . 8 6.5.2 Release by the calling endpoint exchange 8 7 Application service elements and primitives 8 7.1 Primitives between SACF and application process 8 7.1.1 Set_Up request/indication primitive. 8 7.1.2 Answer re
20、quest/indication primitive 9 7.2 Primitives between BCC ASE and SACF. 9 7.2.1 Link_Set_Up request/indication primitive 9 7.2.2 Link_Information request/indication primitive . 9 7.3 ASE descriptions . 9 iv ITU-T Q.2767.1 (06/2000) Page 8 Instruction indicators and interworking 9 8.1 Interworking with
21、 nodes not supporting this feature. 9 8.2 Interworking with DSS2 10 8.3 Interworking with narrow-band ISDN . 10 8.4 Interaction with other capabilities. 10 8.4.1 Point-to-multipoint . 10 8.4.2 Traffic parameters. 10 8.4.3 Look-ahead. 10 8.4.4 Negotiation of traffic characteristics during call setup
22、10 8.4.5 Modification of traffic characteristics during the active phase of the call 10 8.4.6 ATM End System Address (AESA) 10 8.4.7 Call priority. 10 8.4.8 Network generated session ID 10 8.4.9 Frame relay. 10 8.5 Interworking with the first release of soft PVC ITU-T Q.2767.1 (05/98). 10 9 Timers.
23、11 Appendix I Setting of instruction indicators . 11 Appendix II Retry decision 12 ITU-T Q.2767.1 (06/2000) 1 ITU-T Recommendation Q.2767.1 Soft PVC capability 1 Scope This Recommendation contains formats and procedures for supporting soft Permanent Virtual Connections (soft PVCs). Soft PVC capabili
24、ty utilizes the normal procedures of B-ISUP in order to control soft permanent virtual circuit connections between their endpoints. The endpoints are responsible for maintaining the end-to-end circuit by setting up a new switched connection in case the existing switched connection is released or fai
25、ls. The endpoints of a soft PVC are located in the exchanges to which the users of the soft PVC are connected. The endpoint is identifiable by addressing information contained in the call setup signalling, such as an E.164 number plus VPCI/VCI or DLCI value. Figure 1 identifies different reference p
26、oints in a soft PVC using internal SVC connection switching and signalling. T11100980-98UserUserVCorVPSoft PVCcalled endpointVCorVPVCorVPNNIsignallingSoft PVCcalled endpointNNIsignallingNNIsignallingFigure 1/Q.2767.1 Soft PVC configuration Two types of soft PVC are supported: soft permanent virtual
27、path connection (PVPC); and soft permanent virtual channel connection (PVCC). This Recommendation contains the additional message and parameter coding, procedures, ASE descriptions and interworking mapping tables for the support of soft PVCC and soft PVPC services. The procedures for control of soft
28、 PVCCs are applicable to point-to-point and point-to-multipoint procedures. The procedures for control of soft PVPCs follow the additional procedures for switched virtual path connections in ITU-T Q.2766.1. The frame relay endpoints can only be connected by a soft PVCC connection and not by a soft P
29、VPC connection. 2 References The following ITU-T Recommendations and other references contain provisions 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 su
30、bject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility 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. ITU-T Q.2767.1 (06/200
31、0) 2 ITU-T Q.2724.1 (1996), B-ISDN user part Look-ahead without state change for the network node interface. ITU-T Q.2726.2 (1996), B-ISDN user part Call priority. ITU-T Q.2726.3 (1996), B-ISDN user part Network generated session identifier. ITU-T Q.2763 (1999), Signalling System No. 7 B-ISDN User P
32、art (B-ISUP) Formats and Codes. ITU-T Q.2764 (1999), Signalling System No. 7 B-ISDN User Part (B-ISUP) Basic call procedures. ITU-T Q.2766.1 (1998), Switched virtual path capability. ITU-T Q.2931 (1995), Digital subscriber Signalling System No. 2 User-Network Interface (UNI) layer 3 specification fo
33、r basic call/connection control. ITU-T X.76 (2000), Network-to-network interface between public networks providing PVC and/or SVC frame relay data transmission service. 3 Definitions This Recommendation defines the following terms: 3.1 soft PVC called endpoint: Information sent in the forward (or ba
34、ckward) direction indicating the VPCI or VPCI/VCI values in the case of an ATM user or DLCI value in the case of a Frame Relay user, to be used (or used) for the connection segment between the soft PVC called endpoint and a user. 3.2 soft PVC calling endpoint: Information sent in the forward directi
35、on indicating the VPCI or VPCI/VCI values in the case of an ATM user or DLCI value in the case of a Frame Relay user, used for the connection segment between the soft PVC calling endpoint and a user. 4 Abbreviations This Recommendation uses the following abbreviations: DLCI Data Link Connection Iden
36、tifier NNI Network-Node Interface PVC Permanent Virtual Connection PVCC Permanent Virtual Channel Connection PVPC Permanent Virtual Path Connection SVC Switched Virtual Channel UNI User-Network Interface VCI Virtual Channel Identifier VPCI Virtual Path Connection Identifier 5 B-ISDN user part messag
37、es and parameters The modifications to parameters and messages described in this clause are required to support soft PVCs. ITU-T Q.2767.1 (06/2000) 3 5.1 Formats 5.1.1 Soft PVC called endpoint parameter The format of the Soft PVC called endpoint parameter field is shown in Figures 2a and 2b. The par
38、ameter name code allocated to the Soft PVC called endpoint parameter is described in ITU-T Q.2763. 8 7 6 5 4 3 2 1 ext. 1 Coding standard Reserved Selection type Subfield indicator VPCI va lue Subfield indicator VCI value Figure 2a/Q.2767.1 Soft PVC called endpoint parameter field for ATM user If th
39、e DLCI indicator and value exist in the Soft PVC parameter then the VPCI/VCI indicator and value is not needed, i.e. the two subfield parameters are mutually exclusive and only one of the two subfields can exist at one time. Currently the soft PVC called endpoint is coded as follows. 8 7 6 5 4 3 2 1
40、 ext. 1 Coding standard Reserved Selection Type DLCI subfield indicator ext. 0 Spare 0 DLCI (Most significant 6 bits) (Note 1) ext. 0/1 DLCI (2nd most significant 4 bits) 0 0 0 ext. 1 DLCI (3rd most significant 6 bits) Res. 0 (Note 2) ext. 0 DLCI (3rd most significant 7 bits) (Note 3) ext. 1 DLCI (4
41、th most significant 6 bits) Res. 0 (Note 3) NOTE 1 The DLCI is two, three or four octets (i.e. 10 or 16 or 23 bits respectively). The standard default length of the DLCI is two octets. The extension bit mechanism is used to indicate non-default length of the DLCI. NOTE 2 This octet shall only be inc
42、luded when bilateral agreements between the nodes which are endpoints of the soft PVC allow a 3-octet DLCI (16 bits). NOTE 3 These octets shall both be included only when bilateral agreements between the nodes which are endpoints of the soft PVC allow a 4-octet DLCI (23 bits). Figure 2b/Q.2767.1 Sof
43、t PVC called endpoint parameter field for frame relay user ITU-T Q.2767.1 (06/2000) 4Subfields are coded as follows: a) Selection type 0000 0000 Any value 0000 0010 Required value 0000 0100 Assigned value All other values reserved. b) Subfield indicator 0000 0001 VPCI value 0000 0010 VCI value 0000
44、0011 DLCI value All other values reserved. c) VPCI value Two-octet value coded as in the Connection Element Identifier (see ITU-T Q.2763). d) VCI value Two-octet value coded as in the Connection Element Identifier (see ITU-T Q.2763). e) The DLCI value is coded as in ITU-T X.76 without the informatio
45、n element identifier. The default length of DLCI is two octets but can be extended by bilateral agreement to three of four octets (see ITU-T X.76 Figure 10-18). 5.1.2 Soft PVC calling endpoint parameter The format of the Soft PVC calling endpoint parameter field is shown in Figures 3a and 3b. The pa
46、rameter name code allocated to the Soft PVC calling endpoint parameter is described in ITU-T Q.2763. 8 7 6 5 4 3 2 1 ext. 1 Coding standard Reserved Subfield indicator VPCI value Subfield indicator VCI value Figure 3a/Q.2767.1 Soft PVC calling endpoint parameter field for ATM user If the DLCI indica
47、tor and value exist in the Soft PVC parameter then the VPCI/VCI indicator and value is not needed, i.e. the two subfield parameters are mutually exclusive and only one of the two subfields can exist at one time. Currently the soft PVC calling endpoint is coded as follows. ITU-T Q.2767.1 (06/2000) 5
48、8 7 6 5 4 3 2 1 ext. 1 Coding standard Reserved DLCI subfield indicator ext. 0 Spare 0 DLCI (Most significant 6 bits) (Note 1) ext. 0/1 DLCI (2nd most significant 4 bits) 0 0 0 ext. 1 DLCI (3rd most significant 6 bits) Res. 0 (Note 2) ext. 0 DLCI (3rd most significant 7 bits) (Note 3) ext. 1 DLCI (4
49、th most significant 6 bits) Res. 0 (Note 3) NOTE 1 The DLCI is two, three or four octets (i.e. 10 or 16 or 23 bits respectively). The standard default length of the DLCI is two octets. The extension bit mechanism is used to indicate non-default length of the DLCI. NOTE 2 This octet shall only be included when bilateral agreements between the nodes which are endpoints of the soft PVC allow a 3-octet DLCI (16 bits). NOTE 3 These octets shall both be included only when bilateral agreements between the nodes whic
