1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.1990 (07/200 1 ) SERIES Q: SWITCHING AND SIGNALLING Specifications of signalling related to Bearer Independent Call Control (BICC) BICC bearer control tunnelling protocol ITU-T Recommendation Q.1990 (Former
2、ly CCITT Recommendation) ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No. 6 SPECIFICATIONS OF SI
3、GNALLING SYSTEM R1 SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 43 INTERFACE DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBILE NETWORK INTERWORKING WITH SATELLITE MOBILE SYSTEMS INTELLIGENT NETWORK S
4、PECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) BROADBAND ISDN INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q. 1-4.3 Q .4-Q. 5 9 Q.60-Q.99 Q. 100-Q. 1 19 Q. 120-4.249 4
5、.25 0-Q .3 09 4.3 10-4.399 4.400-4.499 Q .500-Q.5 99 Q.600-Q.699 4.7004.799 Q.800-4.849 Q. 8 50-Q.999 Q.lOOO-Q.1099 Q.llOO-Q.1199 Q. 1200-Q. 1699 Q. 1700-Q.1799 Q.190O-Q.1999 Q.2000-4.2999 For further details. please refer to the list of ITU-T Recommendations. ITU-T Recommendation Q.1990 BICC bearer
6、 control tunnelling protocol Summary This Recommendation defines the BICC bearer control tunnelling protocol. The BICC bearer control tunnelling protocol is a generic tunnelling mechanism for the purpose of tunnelling Bearer Control Protocols (BCP) over the “horizontal“ BICC interface between CCUs a
7、nd over the “vertical“ CBC interface between CCU and BCU. This Recommendation defines the BICC bearer control tunnelling protocol, describing the coding and procedures for identification of the tunnelled bearer control protocol. Source ITU-T Recommendation Q. 1990 was prepared by ITU-T Study Group 1
8、 1 (200 1-2004) and approved under the WTSA Resolution 1 procedure on 2 July 2001. ITU-T Q.1990 (07/2001) i FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) i
9、s 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 telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years,
10、 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 the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessa
11、ry standards are prepared on a collaborative basis with IS0 and 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 pos
12、sibfity that the practice or implementation of this Recommendation 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
13、Recommendation development process. As of the date of approval of this Recommendation, ZTU 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 inform
14、ation and are therefore strongly urged to consult the TSB patent database. o ITU 2002 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing fiom ITU. 11
15、 ITU-T Q.1990 (07/2001) CONTENTS 1 2 3 4 5 6 6.1 6.2 7 7.1 7.2 7.3 Scope . References . Terms and definitions . Abbreviations Overview . Tunnelling of bearer control protocols by Q.1990 Protocol . Supported Bearer Control Protocols . Coding of BCTP PDUs . Procedures . Normal Procedures . Abnormal pr
16、ocedures Policing of maximum length tunnelled PDUs ITU-T Q.1990 (07/2001) 1 1 1 1 2 iii ITU-T Recommendation Q.1990 BICC bearer control tunnelling protocol 1 Scope The purpose of this Recommendation is to define the BICC bearer control tunnelling protocol. The BICC bearer control tunnelling protocol
17、 is a generic tunnelling mechanism for the purpose of tunnelling Bearer Control Protocols (BCP) over the “horizontal“ BICC interface between CCUs and the “vertical“ CBC interface between CCU and BCU. This Recommendation defines the BICC bearer control tunnelling protocol, which transports the tunnel
18、led protocol data units (PDU) of the bearer control protocols supported. It describes the coding and procedures for the identification of the tunnelled bearer control protocol. This Recommendation references the specific bearer control protocols that are tunnelled. 2 References The following ITU-T R
19、ecommendations 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 subject to revision; users of this Recommendation ar
20、e therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of currently valid ITU-T Recommendations is regularly published. i ITU-T 4.765.5 (2000), Signalling system No. 7 -Application transport mechanism
21、: Bearer Independent Call Control (BICC). 2 ITU-T 4.1902.1 to 4.1902.4 (2001), SpeciJcations of the Bearer Independent Call Control Protocol (BICC) . 3 ITU-T Q. 1950 (2001), Bearer independent call bearer controlprotocol. 4 ITU-T Q. 1970 (2001), BICC IP bearer control protocol. 3 Terms and definitio
22、ns For the purpose of this Recommendation, the following definiions apply: 3.1 tunnelling PDU generating entity: The entity that populates and transmits the tunnelled PDUs. 3.2 tunnelling PDU receiving entity: The entity that receives and interprets the tunnelled PDUs. 4 Abbreviations This Recommend
23、ation uses the following abbreviations: APM Application Transport Mechanism BCP Bearer Control Protocol BCTP Bearer Control Tunnelling Protocol BCU Bearer Control Unit ITU-T Q.1990 (07/2001) 1 BICC Bearer Independent Call Control BIWF Bearer Interworking Function BVEI BCTP Version Error Indicator CB
24、C Call Bearer Control protocol ccu Call Control Unit CSF Call Serving Function IPBCP IP Bearer Control Protocol MMSF Media MappingBwitching Function PCI Protocol Control Information PDU Protocol Data Unit TPEI Tunnelled Protocol Error Indicator 5 Overview This Recommendation assumes a reliable, sequ
25、enced, point-to-point signalling transport service between peer tunnelling PDU generating and receiving entities. This Recommendation supports the tunnelling of Bearer Control Protocols (BCP) over the following protocols: o BICC protocol. BICC tunnelling makes use of the BICC APM Mechanism, as defin
26、ed in CBC protocol. CBC tunnelling makes use of the H.248 tunnelling package, as defined in ITU-T 4.765.5 i and 6.4/Q.1902.4 2. o 6.9AQ.1950 3. The operation of the tunnelling mechanism is illustrated in Figure 1. Tunnel Figure llQ.1990 - Operation of the BCTP unneiiing mechanism 2 ITU-T Q.1990 (07/
27、2001) 6 Tunnelling of bearer control protocols by Q.1990 Protocol Supported BCP IPBCP 6.1 Supported Bearer Control Protocols The Bearer Control Protocols (BCP) supported by ITU-T Q.1990, are provided in Table 1. Reference ITU-T Q. 1970 4 Table UQ.1990 - Supported bearer control protocols 6.2 Coding
28、of BCTP PDUs The bearer control tunnelling protocol has a binary encoded Protocol Control Information (PCI) field of 2 octets in front of every tunnelled BCP PDU. The first octet of the BCTP Indicator field contains a 1-bit BCTP Version Error Indicator (BVEI) field and a five-bit BCTP version indica
29、tor field. The second octet of the BCTP indicator field contains a 1-bit Tunnelled Protocol Error Indicator (TPEI) field and a six-bit tunnelled protocol indicator field. The format of the BCTP Indicator field is shown in Table 2. Table 214.1990 - BCTP Indicator field 8 7 6 5 4 3 2 1 Octets I O I BV
30、EI I 1 I msb BCTP Version Indicator lsb I 1 I O 1 PEI I msb Tunnelled Protocol Indicator lsb I 2 The Tunnelled Protocol Error Indicator (TPEI) field is coded as follows: O No indication 1 The following codes are used in the Tunnelled Protocol Indicator field: 65 4321 O0 O000 to o1 o111 o1 1000 to o1
31、 1111 10 O000 10 O001 10 O010 not used 10 O011 to 11 o111 Protocol Error Indication, Bearer Control Protocol not supported spare (binary encoded protocols) reserved for national use (binary encoded protocols) I I I IPBCP (text encoded) spare (text encoded protocol) spare (text encoded protocols) ITU
32、-T Q.1990 (07/2001) 3 reserved for national use (text encoded protocols) I 11 1000 to 11 1111 NOTE 1 - The proper transport of BCTP, be it binary or text encoded, is the responsibility of the protocol carrying BCTP. Bit No. 6 may be used to differentiate between the two cases, if needed. See for exa
33、mple Annex A.7/Q.1950: Bearer Control Tunnelling Package. The BCTP Version Error Indicator (BVEI) field is coded as follows: O No indication 1 Version Error Indication, BCTP version not supported The following codes are used in the BCTP Version Indicator field: 5 4321 o O000 o O001 spare o O010 not
34、used o O011 Version 1 of the BCTP protocol (this Recommendation) spare I to 11111 NOTE 2 - Bits 8 and 6 of BCTP indicator octet 1 always have the values “O“ and “l“, respectively. NOTE 3 - Bit 8 of BCTP indicator octet 2 always has the value “O“. 7 Procedures 7.1 Normal Procedures The Tunnelling PDU
35、 Generating Entity populates the BCTP Indicator with the appropriate value to describe the Bearer Control Protocol that is transported in the tunnel and it adds this BCTP Indicator in front of every outgoing PDU. The Tunnelled Protocol Error Indicator is set at the “No indication“ value. The BCTP Ve
36、rsion Indicator indicates the used version of the BCTP Protocol. The BCTP Version Error Indicator is set at the “No indication“ value. Every outgoing PDU shall have the BCTP Indicator field as its first two octets. Upon reception of a tunnelled PDU, the Tunnelling PDU Receiving Entity checks the val
37、ue of the version indicator is supported and then distributes the incoming PDU to the appropriate Bearer Control Protocol handling entity, after inspection and removal of the BCTP Indicator octets. 7.2 Abnormal procedures If the Tunnelling PDU Receiving Entity receives a tunnelled PDU with an unsupp
38、orted value of the BCTP Version Indicator: it generates a two-octet PDU back into the tunnel ody containing the BCTP Indicator field. The BCTP Version Error Indicator is set to the “Version Error Indication, BCTP version not supported“ value. The Tunnelled Protocol Indicator is set to the same value
39、 as the Tunnelled Protocol Indicator value received. The BCTP Version Indicator field contains the version number of the version supported; it sends this PDU back to the Tunnelling PDU Generating Entity that sent it; and 4 ITU-T Q.1990 (07/2001) it informs the control logic in the BIWF (Note). If th
40、e Tunnelling PDU Receiving Entity receives a tunnelled PDU with a known value of the BCTP Version Indicator, but an unknown value of the Tunnelled Protocol Indicator: it generates a two-octet PDU back into the tunnel only containing the BCTP Indicator field. The Tunnelled Protocol Error Indicator is
41、 set to the “Protocol Error Indication, bearer control protocol not supported“ value. The Tunnelled Protocol Indicator is set to the same value as the Tunnelled Protocol Indicator value received; it sends this PDU back to the Tunnelling PDU Generating Entity that sent it; and it informs the control
42、logic in the BIWF (Note). If the Tunnelling PDU Receiving Entity receives a tunnelled PDU with the Tunnelled Protocol Error Indicator value “Protocol Error Indication, Bearer Control Protocol not supported“, and/or if the Tunnelling PDU Receiving Entity receives a tunnelled PDU with the BCTP Version
43、 Error Indicator value “Version Error Indication, BCTP version not supported“: it informs the control logic in the BIWF (Note). NOTE - It is the responsibility of the control logic in the BIWF to take appropriate release actions. The error message in the CBC protocol that carries the tunnel shall ap
44、ply cause code “Interworking unspecified“. However, the control logic in the BIWF is out of the scope of this Recommendation. Procedures for version negotiation and protocol negotiation are for further study. 7.3 The tunnelling PDU generating entity shall police the maximum length of the tunnelled P
45、DUs in order to ensure that the maximum data transfer capabilities of the tunnelling mechanisms in BICC and CBC are not exceeded. These maximum transfer capabilities depend on the capabilities of the underlying signalling transport network supporting the BICC 2 and CBC 3 interfaces. Policing of maxi
46、mum length tunnelled PDUs ITU-T Q.1990 (07/2001) 5 SERIES OF ITU-T RECOMMENDATIONS Series A Series B Series C Series D Series E Series F Series G Series H Series I Series J Series K Series L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V Series X Series Y S
47、eries Z Organization of the work of ITU-T Means of expression: definitions, symbols, classification General telecommunication statistics General tariff principles Overall network operation, telephone service, service operation and human factors Non-telephone telecommunication services Transmission s
48、ystems and media, digital systems and networks Audiovisual and multimedia systems Integrated services digital network Cable networks and transmission of television, sound programme and other multimedia signals Protection against interference Construction, installation and protection of cables and ot
49、her elements of outside plant TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Maintenance: international sound programme and television transmission circuits Specifications of measuring equipment Telephone transmission quality, telephone installations, local line networks Switching and signalling Telegraph transmission Telegraph services terminal equipment Terminals for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communica
