1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Q.1902.6TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(04/2004) SERIES Q: SWITCHING AND SIGNALLING Specifications of signalling related to Bearer Independent Call Control (BICC) Bearer Independent Call Control protocol (Capability Set 2): Gen
2、eric signalling procedures for the support of the ISDN User Part supplementary services and for bearer redirection Amendment 1 ITU-T Recommendation Q.1902.6 (2001) Amendment 1 ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL
3、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 SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4, 5, 6, R1 AND R2 Q.120Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEM
4、S 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 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND
5、 PROTOCOLS FOR IMT-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.1902.6 (2001)/Amd.1 (04/2004) i ITU-T Recommendation Q.190
6、2.6 Bearer Independent Call Control protocol (Capability Set 2): Generic signalling procedures for the support of the ISDN User Part supplementary services and for bearer redirection Amendment 1 Summary This amendment to the ISUP Specification Q.1902.6 (07/2001) contains several modifications in var
7、ious chapters due to an update of the bearer redirection procedure. Source Amendment 1 to ITU-T Recommendation Q.1902.6 (2001) was approved on 13 April 2004 by ITU-T Study Group 11 (2001-2004) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. Q.1902.6 (2001)/Amd.1 (04/2004) FOREWORD The In
8、ternational 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 technical, operating and tariff questions and issuing Recomme
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12、ce with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is r
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16、TU. ITU-T Rec. Q.1902.6 (2001)/Amd.1 (04/2004) iii CONTENTS Page 1) Clause 6.3 Cut-through of new bearer connection . 1 2) Clause 6.5.1 Indication of bearer redirection capability. 1 3) Clause 6.5.2.1.1 Negotiation of bearer redirection capabilities 2 4) Clause 6.5.2.1.2 Set-up of new call leg and b
17、earer connection 2 5) Clause 6.5.2.1.3 Release of old call leg and bearer connection 3 6) Clause 6.5.2.2.2.2 Confirmation and Cut-Through of the new bearer connection. 4 7) Clause 6.5.2.2.3 Release of old bearer connection. 5 8) Clause 6.5.4.2 Temporary reject. 5 ITU-T Rec. Q.1902.6 (2001)/Amd.1 (04
18、/2004) 1 ITU-T Recommendation Q.1902.6 Bearer Independent Call Control protocol (Capability Set 2): Generic signalling procedures for the support of the ISDN User Part supplementary services and for bearer redirection Amendment 1 1) Clause 6.3 Cut-through of new bearer connection Modify clause 6.3 a
19、s follows: Two Three possibilities are provided for the cut-through of the new bearer connection at the BC-Anchor node: Immediate Cut-Through. Late Cut-Through. Automatic cut-through. In the case of Immediate Cut-Through, the new bearer connection is cut-through immediately it is established, accord
20、ing to the procedures for standard bearer setup. In the case of Late Cut-Through, cut-through of the new bearer connection is under control of the CC_Anchor node which sends an explicit cut-through request to the BC-Anchor to trigger cut-through. A sub-case of “late cut-through“ is “automatic cut-th
21、rough“. Cut-through of the backwards media path of the new bearer (and cut-off of the backwards path of the old bearer) is under the control of the BC-Anchor and is triggered when non-silent audio is detected on the backwards media path of the new bearer. In most cases, automatic cut-through of the
22、backwards path of the new bearer is subsequently accompanied by an explicit cut-through request sent from the CC-An to the BC-An to complete full cut-through (forwards and backwards) of the new bearer and initiate tear-down of the old bearer. 2) Clause 6.5.1 Indication of bearer redirection capabili
23、ty Modify clause 6.5.1 as follows: An SN that supports the Bearer Control Anchor node capabilities shall indicate this within the IAM and first backwards Call Control message (ACM or CON) of the original call by including the Bearer Redirection Capability Information element within the BAT APP withi
24、n those messages. In the case of ISNs and GSNs, this indication may be included only if the node itself supports the Bearer Redirection procedures for a BC-Anchor node. In the case of TSNs it may additionally be included if received from the preceding or succeeding node and if the procedures of 6.5.
25、2.3 are supported. (A CMN has no Bearer Interworking Function and so cannot perform the Bearer Control Anchor function.) If the Late Cut-Through option is supported, the Late Cut-Through Indicator shall be set to “Late Cut-Through Supported“, otherwise it shall be set to “Late Cut-Through Not Suppor
26、ted“. If the conference option is supported, the conference indicator of the bearer redirection capability information element shall be set to “Conference Supported“, otherwise it shall be set to “Conference Not Supported“. If the “Bi-Casting“ option is supported, the bi-casting indicator of the bea
27、rer redirection capability information element shall be set to “Bi-Casting Supported“, otherwise it shall be set to “Bi-Casting Not supported“. 2 ITU-T Rec. Q.1902.6 (2001)/Amd.1 (04/2004) If the “Automatic cut-through“ option is supported, the automatic cut-through indicator of the bearer redirecti
28、on capability information element shall be set to “Automatic cut-through supported“, otherwise it shall be set to “Automatic cut-through not supported“. The compatibility information of the bearer redirection capability shall be set so as to cause the information element to be discarded by nodes tha
29、t do not support bearer redirection. 3) Clause 6.5.2.1.1 Negotiation of bearer redirection capabilities Modify clause 6.5.2.1.1 as follows: When the CC-Anchor node has decided to invoke bearer redirection, an APM is sent to the preceding node with the action indicator in the BICC_Data request primit
30、ive set to “Bearer Redirect“ and including Bearer Redirection Indicator “Redirect Backwards Request“ or “Redirect Forwards Request“ as appropriate depending on the capability of the Redirecting-to node, i.e., the CC-Anchor node determines whether the Forward or Backward procedures are to be used tow
31、ards the Redirecting-to node in a way similar to how a node initiating a new call determines whether the Forwards or Backwards procedure should be used towards that node. The Bearer Redirection Indicators are also included in the BICC_Data request primitive. If Late Cut-Through is desired and the La
32、te Cut-Through indicator received in the Bearer Redirection Capability Information Element in the IAM was set to “Late Cut-Through Supported“, then a Bearer Redirection Indicator “Late Cut-Through Requested“ shall be included. If conferencing of the new and old bearers (during the intermediate stage
33、 when both bearers have been created) is desired, and the conferencing indicator received in the bearer redirection capability information element in the IAM was set to “Conferencing Supported“, then a bearer redirection indicator “Conference requested“ shall be included. If bi-casting of media on t
34、he forwards media path of the old and new bearers (during the intermediate stage when both old and new bearers have been created) is desired, and the bi-casting indicator received in the bearer redirection capability information element in the IAM was set to “Bi-casting supported“, then a bearer red
35、irection indicator “Bi-casting requested“ shall be included. If automatic cut-through of the backwards media path of the new bearer (when non-silent audio is detected) is required, and the automatic cut-through indicator of the bearer redirection capability information element in the IAM was set to
36、“Automatic cut-through supported“, then a bearer redirection indicator “Automatic cut-through requested“ shall be included. On receipt of a BICC_Data indication primitive (corresponding to an APM received from the preceding node (BC-Anchor) with action indicator set to “Connect Backward“ or “Connect
37、 Forward“, CC-Anchor node, the procedures of 6.5.2.1.2 followed by 6.5.2.1.3 apply. 4) Clause 6.5.2.1.2 Set-up of new call leg and bearer connection Modify clause 6.5.2.1.2 as follows: To initiate set-up of the new call leg and bearer connection the service at the CC-Anchor node uses the stored IAM
38、information to construct an IAM to be sent to the Redirecting-to node. The APP with Application Context Identifier “BAT ASE“ included in the IAM shall only include the information elements from the APP received by the CC-Anchor node in 6.5.2.1.1. ITU-T Rec. Q.1902.6 (2001)/Amd.1 (04/2004) 3 The CC-A
39、nchor node subsequently behaves as follows: BAT ASE information received from the Redirecting-from node is passed on to the BC-Anchor according to standard CMN procedures. BAT ASE information received from the Redirecting-to node is passed on to the BC-Anchor according to standard CMN procedures but
40、 with a Bearer Redirection Indicator “new connection identifier“ included. BAT ASE information received from the BC-Anchor node containing a Bearer Redirection Indicator “new connection identifier“ is passed on to the Redirecting-to node according to standard CMN procedures but with the Bearer Redir
41、ection Indicator “new connection identifier“ removed. BAT ASE information received from the BC-Anchor node not containing a Bearer Redirection Indicator “new connection identifier“ is passed on to the Redirecting-from node according to standard CMN procedures. The behaviour of the CC-Anchor node wit
42、h respect to other messages/information depends on the application invoking Bearer redirection. The CC-Anchor node waits for a BICC_Data indication primitive (corresponding to an APM) with Action Indicator set to “Connected“ or with Action Indicator set to “Bearer Redirect“ and including Bearer Redi
43、rection Indicator “redirect bearer connected“ to be received from the BC-Anchor node. In the former case, this indication is passed onwards to the Redirecting-to node. In the case of Late Cut-Through, when Cut-through of the new connection is required, the CC-Anchor node shall send a BICC_Data reque
44、st primitive (in association with any suitable message) with Action indicator set to “Bearer Redirect“ and including Bearer Redirection Indicator “redirect cut-through request“ towards the BC-Anchor node. Under the conferencing scenario, the endpoints (at the BC-An) of the old and new bearers will b
45、e conferenced together, however, the CC-An still controls the cut-through of the new bearer (and consequently the cut-over from the old bearer to the new bearer). To achieve cut-through under this scenario, the CC-An node shall send a BICC_Data request primitive (in association with any suitable mes
46、sage) with action indicator set to “Bearer Redirect“ and including bearer redirection indicator “redirect cut-through request“ towards the BC-Anchor node. Similarly, when bi-casting of the forwards media path (at the BC-An) on the old and new bearers is being used, the CC-An still controls the “cut-
47、over“ point (this applies to both the “automatic cut-through“ and “late cut-through“ bi-casting scenarios). Under this scenario, to achieve cut-through (of the backwards media path of the new bearer (and subsequently cut-off of the old bearer), the CC-Anchor node shall send a BICC_Data request primi
48、tive (in association with any suitable message) with action indicator set to “Bearer Redirect“ and including bearer redirection indicator “redirect cut-through request“ towards the BC-Anchor node. The new bearer set-up procedure is now complete. 5) Clause 6.5.2.1.3 Release of old call leg and bearer
49、 connection Modify clause 6.5.2.1.3 as follows: When the controlling application requires the release of the old call leg and bearer to the Redirecting-from node, the CC-Anchor node sends an APM to the preceding node with the action indicator in the BICC_Data request primitive set to “Bearer Redirect“ and including Bearer Redirection Indicator “redirect bearer release request“. On receipt of an APM from the preceding node with the action indicator in the BICC_Data indication primitive set to “Bearer Redirect“ and including Bearer Redirection Indicator “redi
