1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Annex B Q.601 iQ.695 INTERWORKING OF SIGNALLING SYSTEMS (03/93) INTERWORKING OF SIGNALLING OF INTERWORKING SYSTEMS - NARRATIVE PRESENTATION Annex B to ITU-T Recs. Q.601 to Q.695 (Previously “CCIlT Recommendat
2、ions“) FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecommunication Union. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunicati
3、ons on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. Annex B to ITU-T Recommendations Q.601 to Q.695 was revised
4、 by the ITU-T Study Group XI (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCITT ceased to exist as of 28 February 1993. In its place, the ITU Telecommunication Standardi
5、zation Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to references containing the acronyms “CCI
6、TT, CCIR or IFRJ3” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the new ITU structure. 2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both
7、a telecommunication administration and a recognized operating agency. O ITU 1994 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 from the ITU. _ S
8、TD*ITU-T RECMN Q*b01-Q*b75 ANNE-ENGL 1773 W 98b2571 Ob31b53 7b7 H CONTENTS Page B. 1 Introduction . 1 B.2 Narrative presentation of the various interworking cases . 3 Recs. Q.601-Q.695 - Annex B (03/93) 1 STDOITU-T RECMN d*bOL-Q-b75 ANNE-ENGL 1773 YBb2.571 Ob31b5Y bT5 M Annex B Interworking of signa
9、lling systems - Narrative presentation of interworking (Helsinki, 1993) (This annex forms an integral part of Recommendations Q.601-Q.695) B. 1 Introduction B.l.l Narrative presentation Recommendation Q.601 explains the change from narrative to SDL presentation and that the SDL method facilitates th
10、e specification of interworking with future signalling system. But, for ISUP, some additional information, that is relevant to interworking, may be useful: - - - - - the coding of the messages; taking into account of supplementary services; supplementary informations about the call failure handling;
11、 taking into account of the sequencing of the received messages; handling of the access information. This annex must be read and used as a complement of the CCITT interworking SDL specifications and not as an independent specification. Only the information being a matter of interworking is described
12、. Hence, no information is given concerning the: - nationalhternational call indicator; - end-to-end method indicator; - end-to-end information indicator; - SCCP method indicator; - - - continuity check indicator in interworking cases R2, No. 5 to ISUP; COT message in interworking cases R2, No. 5 to
13、 ISUP; handling of the call, if only signalling systems having the capabilities of ISUP shall be used (e.g. ISUP preference indicator received is set to “ISUP required”). B.1.2 Working assumptions - TUP does not support any supplementary service (e.g. calling line identification). TUP supports the “
14、digital connectivity”. TUP only supporting IAM is described. - B.1.3 Miscellaneous interworking aspects B.1.3.1 Interworking handling of the echo control device indicator (or the incoming half echo suppressor indicator) of ISUP ACM (or TUP) of the address complete message (ACM) in ISUP (or TUP) In o
15、rder to send more accurate information in the backward direction, the following interworking handling is proposed which can be used independently of the Echo control procedures (described in Recommendation 4.724 or Q.767). Recs. Q.601-Q.695 - Annex B (03/93) 1 STD*ITU-T RECMN d*bOL-Q-b75 ANNE-ENGL 1
16、773 48b257L Ob3Lb55 531 Intenvorking ISUP + R2, No. 5 - If the bit E of the echo control device indicator received in the IAM is coded “O” (no outgoing half echo control device is included), then the bit N of the echo control device indicator of the ACM is coded “O”. IAM (E = O)+ tACM (N = O) - If t
17、he bit E of the echo control device indicator received in the IAM is coded “1” (an outgoing half echo control device is included): a) if an incoming half echo control device is locally included or if it is known from the routing data available in the exchange that an incoming half echo control devic
18、e can be inserted beyond the interworking point, then the bit N of the echo control device indicator of the ACM is coded “1”; b) if it is known from the routing data available in the exchange that no incoming half echo control device can be included beyond the intenvorking point and no incoming half
19、 echo control device is locally available, then the bit N of the echo control device indicator is coded “O”. Intenvorking ISUP + TUP, ISUP - If the bit E of the echo control device indicator received in the IAM is coded “O” (no outgoing half echo control device is included), the bit N of the echo co
20、ntrol device indicator in the ACM is coded as received in the ACM (TUP: bit D of the incoming half echo suppressor, ISUP: bit N of the echo control device indicator). - If the bit E of the echo control device indicator received in the IAM is coded “1” (an outgoing half echo control device is include
21、d): a) if the incoming half echo control is locally included, then the bit N of the echo control device indicator of the ACM is coded “1”: b) if no incoming half echo control device is locally included, the bit N of the echo control device indicator in the ACM is coded as received in the ACM (TUP: b
22、it D of the incoming half echo suppressor indicator, ISUP: bit N of the echo control device indicator). The same principles might be followed when the incoming signalling system is TUP. Interworking TUP -+ ISUP - If the bit G of the message indicators received in the IAM is coded “O” (outgoing half
23、echo suppressor not included), the bit D of the incoming half echo suppressor indicator in the ACM is coded as received in the ACM (bit N of the echo control device indicator). - If the bit G of the message indicators received in the IAM is coded “1” (outgoing half echo suppressor included): a) if t
24、he incoming half echo control is locally included, then the bit D of the incoming half echo suppressor indicator of the ACM is coded “I”; b) if no incoming half echo control device is locally included, the bit D of the incoming half echo suppressor indicator in the ACM is coded as received in the AC
25、M (bit N of the echo control device indicator). B.1.3.2 Handling of the called partys category and the charge indicator when interworking TUP to ISUP When intenvorking from TUP to ISUP the theoretical number of combinations of the ISUP backward call indicators (charge, called partys category) implie
26、s some choices since some information may be lost in TUP. 2 Recs. Q.601-Q.695 - Annex B (03/93) It is proposed to transfer the charge and the called partys category indicators as follows: - payphone + no charge + ADWAFX - payphone + charge + ADWAFX ordinary + no charge + ADN/AFN - - ordinary + charg
27、e + ADC/AFC no indic. + no charge + ADN/AFN - - no indic. + charge + ADC/AFC payphone + no indic. -+ ADWAFX - - ordinary + no indic. -+ ADC/AFC no indic. +no indic. -+ ADC/AFC - B.1.3.3 Transfer of no charge or charge information in the Answer message when interworking TUP to ISUP The charge or no c
28、harge information may be received in the backward call indicators in the successive Address complete message (ACM), Call progress message (CPG) and Answer message (ANM). When interworking from TUP to ISUP, this information is transferred as follows: - If “charge” is received in the charge indicator
29、in the ANM, ANC is sent. If “no charge” is received in the charge indicator in the ANM, ANN is sent. - - If “no indication” is received in the charge indicator in the ANM or no backward call indicators are received in the ANM, ANC is sent. With this proposal, ANC may be sent for a call where an addr
30、ess complete no charge message was previously sent. It is assumed that it does not result in charging the call. B.2 Narrative presentation of the various interworking cases B.2.1 Interworking of Signalling System ISUP to No. 5 B.2.1.1 Successful call set-up B.2.1.1.1 Circuit seizure The seizure sign
31、al is sent when the following conditions are fulfilled: - if the continuity check indicator received in the IAM indicates that continuity check is not required; or - if this indicator indicates that it is “required on this circuit” or it is “performed on a previous circuit”, on receipt of the Contin
32、uity message (continuity check successful); and - the end-of-pulsing condition is determined: by receipt of ST, or if the fixed or maximum of number length is reached, or at expiry of the timer (4-6 seconds specified in the Recommendation 4.152) if the minimum number of digits has been received. B.2
33、.1.1.2 Address information sending sequence The sending sequence of address information is specified in the Recommendation Q.107. Recs. Q.601-Q.695 - Annex B (03/93) 3 The language or discriminating digit is coded according to the ?calling party?s category? received in the IAM: IAM category O00 1 O0
34、10 O01 1 O100 O101 o1 10 o111 1000 1010 101 1 1100 1101 1111 French English German Russian Spanish * * * ordinary priority data test call payphone R2 language or discriminating digit I. 1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.10 1.10 1.10 not subject to intenvorking 1.10 1.10 * Available to Administrations
35、for selecting a particular language by mutual agreement. B.2.2.1.1.2 Calling partys category On receipt of A-5 (category request), the category sent in R2 is according to the “calling partys category” received in the IAM: IAM category O001 0010 O01 1 O100 O101 1010 101 1 1100 1101 1111 1010 * Availa
36、ble to Administrations for selecting a particular language by mutual agreement. B.2.3.1.1.2 Message indicators bits BA: nature of address indicator 10 if terminating call 11 if transit call bits DC: nature of circuit indicator O0 (no satellite circuit in the connection) if the received nature of the
37、 connection indicator is coded “00” (no satellite circuit in the connection) and the incoming and outgoing circuits are not satellite circuits O1 (one satellite circuit in the connection) in the other cases bits FE: continuity check indicator O0 if the received continuity check indicator is coded “0
38、0” and a continuity check is not performed on the outgoing circuit O1 if a continuity check is performed on the outgoing circuit 10 if the received continuity check indicator is coded “10” or “01” and a continuity check is not performed on the outgoing circuit bit G: echo suppressor indicator see Re
39、commendation Q. 1 15 bit H: incoming international call indicator O bit I: redirected call indicator O Recs. Q.601-Q.695 - Annex B (03/93) 9 STD-ITU-T RECMN Q-bOL-Q-b95 ANNE-ENGL 1993 m 48b2591 0b3Lbb3 608 W bit J: all digital path required indicator O if the received Transmission medium requirement
40、 parameter is coded “00000000” or “00000011” (speech or 3.1 kHz audio) 1 if the received Transmission medium requirement parameter is coded 00000010” (64 kbis unrestricted). bit K: signalling path indicator O (any path) if the received Interworking indicator is coded “1” (interworking encountered) 1
41、 (all Signalling System No. 7 path) if the received Interworking indicator is coded “O” (no interworking encountered) B.2.3.1.2 Continuity message The continuity signal is sent after completion of all the following actions: - - - the continuity check performed on the outgoing circuit, if it is to be
42、 made, is completed; the speech path across the exchange has been checked and found correct (see 1.414.724); and if the continuity check indicator in the received Initiai address message indicates that continuity check is being (has been) performed on previous circuit(s), receipt of a continuity mes
43、sage (continuity check successful) from the preceding exchange. The completion of the transmission path occurs as follows: - if continuity check is not required on the incoming circuit and on outgoing circuit and is not performed on previous circuit, through connection should occur after sending the
44、 Initial address message; in the other cases, through connection should occur when the continuity signal is sent (see Recommenda- tion Q.724). - B.2.3.1.3 General request message B.2.3.1.3.1 Calling party category request On receipt of a calling party category request received in a General request m
45、essage (GRQ), the calling party category sent in the General forward set-up information message (GSM) is the same as in the sent initiai address message (see subclause “Initial address message”). B.2.3.1.3.2 Calling line identity request On receipt of a calling line identity request received in a Ge
46、neral request message (GRQ), the calling line identity sent in the General forward Set-up information message (GSM) is as follows: - address indicators: bits BA: nature of address indicator 11 (international number) bit C: calling line identity presentation indicator 1 (restricted) bit D: incomplete
47、 calling line identity indicator O (no indication) - number of address indicator bits DCBA O000 calling line identity not available indicator B.2.3.1.4 Address complete On receipt of a Address complete message on the TUP side, the Address complete message is sent, coded as follows: - backward-call i
48、ndicators bits BA: charge indicator 10 (charge) if ADC, ADX, AFC or AFX is received O1 (no charge) if ADN or AFN is received bits DC: Called partys status indicator O0 (no indication) if ADC, ADN, ADX is received O1 (subscriber free) if AFC, AFN or AFX is received 10 Recs. Q.601-Q.695 - Annex B (03/
49、93) bits FE: Called partys category indicator O0 (no indication) if ADC, ADN, AFC, AFN is received 10 (payphone) if ADX or AFX is received bit I: Interworking indicator O (no interworking encountered) if the received signalling path indicator is coded “1” (all Signalling System No. 7 path) 1 (interworking encountered) if the received signalling path indicator is coded “O” (any path) bit K: ISUP indicator O (not used ali the way) bit M: ISDN access indicator O (terminating access non-ISDN) bit N: Echo control device indicator see introduction, subclause B. 1.3.1 B.2.3.1
