1、CEPT T/CS*21-05*E 3 E 2326414 0004590 O = Page 1 TCs21-05E Recommendation T/CS 21-05 (Cannes 1983) CALL HANDLING SEQUENCES FOR SUPPLEMENTARY SERVICES FAMILY “MALICIOUS CALL IDENTIFICATION” Recommendation proposed by Working Group T/WG 11 “Switching and Signalling” (CS) Text of the Recommendation ado
2、pted by Commission “Telecommunications”: “The European: Conference of Postal and Telecommunications Administrations, considering - that the operational requirements established for this service are defined in the “Handbook on services and - that the implementation of the service has a very great imp
3、ortance due to its legal implications; - that operation of the service requires the utilization of the additional signalling feature as defined in Recommenda- tion T/CS 20-26 2 and of the automatic number identication feature (ANI) as defined in Recommendation T/CS - that a recommended way of specif
4、ying additional signalling information and its flow is according to Recommends- tion T/CS 21-01 4; - that the definition of a standardized malicious call identication (MCI) call handling sequence is useful, even in the case that the MCI service across the border will be provided on a bilateral agree
5、ment only; - that it is advantageous to have a common set of service instructions for the different members of the services family, such that international interworking is possible whichever service member is applied on both sides of the border, recommends facilities offered to the subscriber in mod
6、ern telephone systems” l; O 20-06 3; - that member administrations adopt the call handling sequences outlined below in providing MCI service.” 1. INTRODUCTION This Recommendation specifies the call handling sequences for the two different options (see paragraph 2.) dened for the supplementary servic
7、es family “Malicious call identification (MCI)” i. The different possible requirements of the service are defined in the SF Handbook, Family 14.2, in particular, the following services of this family have been considered: 14.2.3: 14.2.4: 14.2.6: A unique set of service instructions is defined to cat
8、er for the above mentioned services; the rdevant list of the additional signalling service instructions is indicated in paragraph 5. Moreover the call handling sequences for different services and options are depicted in the call handling sequence charts. MCI, request for identification during call
9、by means of register recall procedure; MCI, request for identification during call by means of a special subscriber signal; MCI, request for identification after call. 2. DIFFERENT OPTIONS OF THE SERVICE Two different options of the service have been dened: Option 1: MCI with hold; Option 2: MCI wit
10、hout hold. 2.1. In option 1, in addition to the identication of the calling subscriber, the holding of the connection is requested (e.g. for legal reasons). In this case, the clearing of the connection wil become subject to the receipt of the clear-back signal. In any case, even if the connection is
11、 held, the charging of the call should be suspended at the calling partys on-hook. . 2.2. In the second option, only the identification of the calling subscriber is requested; the clearing of the connection is handled in the normal way. O Edition of May 15, 1986 - TICS 21 -05 E Page 2 3. CALL HANDLI
12、NG SEQUENCE CHARTS Sequence charts 1 and 2 depict the MCI call handling respectively for the options 1 and 2. In both cases the connection is considered as fully served by additional signalling. The service instructions (SI) and the activities in the originating and destination exchange are shown. A
13、ll the SI are sent between A and B exchanges and need not be interpreted by intermediate exchanges unless otherwise stated. In certain cases the MCI service cannot operate for administrative/technical reasons; in such cases the relevant exchange (originating or transit) will send forward the “ANI no
14、t available” SI instead of the calling line identity. Edition of May 15, 1986 Edition of May 15, 1986 The speech path is switched through to the destination exchange. Ringing tone CEPT T/CS*ZL-OS*E 83 m 2326434 0004572 4 m Call arrival signal TICS 21-05 E Page 3 CALL HANDLING SEQUENCE CHART 1 Normal
15、 caii to a free subscriber with ?MCI with hold? activated RNR 10 20 30 40 50 60 70 80 .go 100 110 120 130 Destination exchange I Originating exchange - Normal call set-up procedure w The category of the cailed subscriber is analysed. Category ?MCI with hold? is detected. A general request message is
16、 returned which contains 3 S.1.s. - Automatic number identification - MCI encountered (optional) - Hold required S.I. transfer 4 The calling line is identified (if possible). I Fuil/partial ANI or ANI not available b The received information is stored in the exchange. B subs. free Answer 4 Ringing t
17、one ceased. Speech path completed. Answer ANSWERED CALL I ANSWERED CALL CEPT T/CS*21-05*E 83 I 2326414 0004593 b W TICS 21 -05 E Page 4 RNR 200 210 220 230 300 305 310 320 325 330 340 3 50 MCI request during a call (SF handbook: service 14.2.3, 14.2.4) Originating exchange Destination exchange ANSWE
18、RED CALL If calling subs. clears first then continuation at RNR 500. MCI-REQUEST BEFORE CLEARANCE Alternative continuation from RNR 220. ANSWERED CALL If called subs. gives MCI-request before clearing then continuation at RNR 300. 4 Clear Continuation at RNR 620. MCI request from called subs. 44 MCI
19、 print-out (optional) 4 (Optional) print-out activated with the following information : - calling line identity; - called line identity; - time and date. CALL CONTINUES - HOLD PREPARED If caiiing subs. clears then connection is held and charging- is stopped. Print-out activated with the following in
20、formation : - calling line identity; - called line identity; - time and date. MCI audible conrm. + CALL CONTINUES - HOLD PREPARED -_- I Connection is held if called subs. clears. HELD CONNECTION Continuation at RNR 610 Edition of May 15, 1986 CEPT T/CS*21-05*E 83 U 232b414 0004594 B Originating exch
21、ange TICS 21 -05 E Page 5 Destination exchange MCI request after Cali (SF handbook: service 14.2.6) Edition of May 15, 1986 RNR 400 405 410 420 425 430 440 450 460 470 ANSWERED CALL If calling subs. clears first then continuation at RNR 500. ANSWERED CALL Clear Y Time-out to receipt of “MCI request”
22、 started. If time-out expires the normal clear sequence applies (see RNR 620). MCI request 44 MCI print-out (optional) 4 (Optional) print-out activated with the following information: - calling line identity; - called line identity; - time and date. Print-out activated with the following information
23、: - calling line identity; - called line identity; - time and date. MCI audible confirm. HELD CONNECTION Continuation at RNR 610 CEPT T/CS*21-05*E 83 E 2326434 O004595 T E TICS 21-05 E Page 6 Caiiing subscriber clears 6rst (ail services) RNR 500 510 520 530 540 550 555 560 570 580 590 Originating ex
24、change Destination exchange I Alternative continuation from RNR 210 and 405 Clear received from calling subscriber. Charging is stopped. Connection is held. Other party clear (optional) N.B.: The procedure from RNR 530 to RNR 590 is optional. Calling subs. held time-out started. If time-out expires
25、then the normal clear sequence applies (see RNR 620). If MCI request received then cont. at RNR 310 Clear 4 Calling subs. held time-out is stopped. Continuation for services 14.2.3 and 14.2.4 at RNR 620. Continuation for service 14.2.6 at RNR 420. Edition of May 15, 1986 CEPT T/CS*ZL-O5*E 83 232b414
26、 0004576 L Originating exchange TICS 21 -05 E Page 7 Destination exchange Cont. from RNR 350 or 470. Action by maintenance staff to release held connection (aii services). RNR 610 620 630 640 650 660 END Edition of May 15, 1986 CEPT T/CS*21-05*E 83 232b414 0004597 3 TICS 21-05 E Page 8 CALL HANDLING
27、 SEQUENCE CHART 2 Normal call to a free subscriber with “MC3 without hold” activated RNR 700 710 720 730 740 750 760 770 780 790 800 810 820 Originating exchange Destination exchange I Normal call set-up procedure w The category of the cailed subscriber is analysed. Category “MCI without hold” is de
28、tected. A general request message is returned which contains 2 S.1.s. - Automatic number identification; - ,MCI encountered (optional). , S.I. transfer 4 The calling line identity is sent (if possible). I Fuil/partial ANI or ANI not available b The received information is stored in the exchange. B s
29、ubs. free The speech path is switched through to the destination exchange. Ringing tone Call arrival signal f- Answer I l 4 Ringing tone ceased. Speech path completed. Answer ANSWERED CALL ANSWERED CALL I - Edition of May 15, 1986 Edition of May 15, 1986 Originating exchange CEPT T/CS*ZL-OS*E 83 W 2
30、326434 0004598 5 Destination exchange T/CS 21-05 E Page 9 RNR 900 910 920 END 1009 1005 1010 1020 END The MCI information is erased oniy on the clearing of the called subs. in case of no MCL request. END CALLED SUBS. CLEARS BEFORE GIVING MCI REQUEST Alternative cont. from RNR 900. Clear 4 Clear back
31、 4 Normal clear procedure * The MCI information is erased. END CEPT T/CS*21-O5*E 83 232b414 0004577 7 TICS 21 -05 E Page 1 O RNR 1100 1110 1120 1125 1130 MCI request during a call (SF handbook: service 14.2.3, 14.2.4) Originating exchange Destination exchange CALLED SUBS. GIVES MCI REQUEST Alternati
32、ve cont. from RNR 900. MCI request called subs. 44 MCI print-out (optional) t (Optional) print-out activated with the following information: - calling line identity; - called line identity; - time and date. Print-out activated with the following information: - calling line identity; - called line id
33、entity; - time and date. MCI audible conrm. + _- CALL CONTINUES I CALL CONTINUES Edition of May 15, 1986 CEPT T/CS*21-05*E 3 2326424 O004600 T TICS 21 -05 E Page 11 MCI request after call (SF handbook: service 14.2.6) RNR 1200 1210 1220 1230 1240 1245 1250 END 1260 1270 1280 1290 END Destination exc
34、hange I Originating exchange ANSWERED CALL Clear back ANSWERED CALL Clear Normal clear procedure Time-out to receipt of “MCI request” is started. If MCI request received from B-subs. within time-out period continuation at RNR 1260. Time-out expires : MCI information is erased. END Alternative cont.
35、from RNR 1240. MCI request 4 MCI print- - called line identity; - time and date. N.B.: If calling subs. goes on-hook rst the normal clearing procedure applies. END Print-out activated with the following information: - caing line identity; - called line identity; - time and date. MCI audible conrm. +
36、 _ Edition of May 15, 1986 CEPT T/CS*ZL-OS*E 83 = 232b4L4 0004bOL L TICS 21 -05 E Page 12 4. INTERWORKING WITH NETWORK PARTS WITHOUT ADDITIONAL SIGNALLING Sequence chart 3 depicts, as an example, the case in which the required service instructions can be handled only between the destination exchange
37、 and an intermediate exchange, but not on the incoming link of the intermediate exchange. At the receipt of the service instructions ANI -t MCI encountered, the transit exchange should then send forward all available information such as the incoming trunk and transit exchange identity. Provision may
38、 be made to hold the connection on the incoming link, if possible, irrespective of whether hold is required or not, as this is the only way of tracing the calling subscriber. CALL HANDLING SEQUENCE CHART 3 Example of a case in which additional signalling is available only between intermediate and de
39、st. exchange. Normal call to a free subscriber with “MCI with/without hold” activated RNR 1300 1310 1320 1330 1340. 1350 1360 Intermediate exchange Destination exchange I Normal call set-up procedure bb The category of the called subscriber is analysed. Category “MCI with/without hold” is detected.
40、A general request message is returned with the relevant S.1.s. S.I. transfer 4 The available information is sent. I Inc. trunk and transit exchange identity b Provision may be made to hold the connection of the incoming link (if possible). Continuation as in sequence chart 1 RNR 70 or, optionally, c
41、hart 2 RNR 760 in case of MCI without hold a Edition of May 15, 1986 CEPT T/CS*ZL-OS*E 83 W 232b4L4 0004602 3 5. 5.1. 5.2. 5.3. 5.4. 5.5. 5.6. 5.7. 5.8. TICS 21 -05 E Page 13 LIST AND DEFINITIONS OF SERVICE INSTRUCTIONS The service instructions (SI) according to Recommendation T/CS 20-26 required fo
42、r operation of the supplementary service are listed below. ANI required: a backward (circuit related) SI sent, in the cail set-up phase, to request the calling subscribers number. MCI encountered: an optional backward (circuit related) SI sent, in the call set-up phase, together with “ANI required”
43、to indicate that the ANI information is required for the MCI service, Hold required: a backward (circuit related) SI sent, in the call set-up phase, to indicate that the call, when in the conversation phase, may only be cleared after clear back has been sent. Calling line identity: a forward (circui
44、t related) SI sent to the B exchange in answer to ANI required containing sufficient information to identify the calling subscribers number. ANI not available: a forward (circuit related) SI sent to the B exchange in answer to ANI required containing the information that the calling subscribers numb
45、er cannot be provided. Incoming trunk and transit exchange identity: a forward (circuit related) SI sent from an intermediate exchange to the B exchange, in case of interworking with network parts without additional signalling, in answer to ANI required + MCI encountered. It contains the identities
46、of the intermediate exchange and its incoming trunk on which the cail has been established. Other party cleared: an optional forward (circuit related) SI sent to the B exchange, only in the case of MCI with hold, to inform the B exchange that the A-party has cleared: MCI print-out: an optional circu
47、it independent SI sent, either during the conversation phase or after the disconnection, to the A-exchange to obtain there the print-out of the MCI information. It, optionally, contains ail the information to be printed out. References i CEPT Handbook on services and facilities offered to the subscr
48、ibers in modern telephone systems. Prepared by CEPT Working Group SF. 3-rd issue 1981. 2 CEPT Recommendation T/CS 20-26. Additional signalling. 3 CEPT Recommendation T/CS 20-06. Automatic number identiJication. 4 CEPT Recommendation T/CS 21-01. Call handling informaiion fzow. Edition of May 15, 1986
