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  7.                                                       Figure 1/Q.724, p. 1
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  15.                                                       Figure 2/Q.724, p. 2
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  21.                                    Figure 3/Q.724 (feuillet 1 sur 7), p. 3
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  27.                                    Figure 3/Q.724 (feuillet 2 sur 7), p. 4
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  33.                                    Figure 3/Q.724 (feuillet 3 sur 7), p. 5
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  39.                                    Figure 3/Q.724 (feuillet 4 sur 7), p. 6
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  45.                                    Figure 3/Q.724 (feuillet 5 sur 7), p. 7
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  51.                                    Figure 3/Q.724 (feuillet 6 sur 7), p. 8
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  57.                                    Figure 3/Q.724 (feuillet 7 sur 7), p. 9
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  71.                                                      Figure 4/Q.724, p. 10
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  77.                                                      Figure 5/Q.724, p. 11
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  83.                                   Figure 6/Q.724 (feuillet 1 sur 2), p. 12
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  89.                                   Figure 6/Q.724 (feuillet 2 sur 2), p. 13
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  95.                                                      Figure 7/Q.724, p. 14
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  101.                                   Figure 8/Q.724 (feuillet 1 sur 4), p. 15
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  107.                                   Figure 8/Q.724 (feuillet 2 sur 4), p. 16
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  113.                                   Figure 8/Q.724 (feuillet 3 sur 4), p. 17
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  119.                                   Figure 8/Q.724 (feuillet 4 sur 4), p. 18
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  125.                                                      Figure 9/Q.724, p. 19
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  137.                                                     Figure 10/Q.724, p. 20
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  143.                                                     Figure 11/Q.724, p. 21
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  149.                                                     Figure 12/Q.724, p. 22
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  155.                                                     Figure 13/Q.724, p. 23
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  161.                                  Figure 14/Q.724 (feuillet 1 sur 2), p. 24
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  167.                                  Figure 14/Q.724 (feuillet 2 sur 2), p. 25
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  173.                                  Figure 15/Q.724 (feuillet 1 sur 2), p. 26
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  179.                                  Figure 15/Q.724 (feuillet 2 sur 2), p. 27
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  185.                                  Figure 16/Q.724 (feuillet 1 sur 2), p. 28
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  191.                                  Figure 16/Q.724 (feuillet 2 sur 2), p. 29
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  203.                                  Figure 17/Q.724 (feuillet 1 sur 2), p. 30
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  209.                                  Figure 17/Q.724 (feuillet 2 sur 2), p. 31
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  215.                                  Figure 18/Q.724 (feuillet 1 sur 2), p. 32
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  221.                                  Figure 18/Q.724 (feuillet 2 sur 2), p. 33
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  227.                                  Figure 19/Q.724 (feuillet 1 sur 2), p. 34
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  233.                                  Figure 19/Q.724 (feuillet 2 sur 2), p. 35
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  238.  
  239.                References
  240.  
  241.  
  242.        [1]         CCITT Recommendation Sending sequence of numerical  (or
  243.        address) signals , | Rec. Q.107.
  244.  
  245.        [2]          CCITT  Recommendation  Performance  requirements  ,  |
  246.        Rec. Q.504.
  247.  
  248.        [3]         CCITT Recommendation Special release arrangements  ,  |
  249.        Rec. Q.118.
  250.  
  251.        [4]             CCITT     Recommendation      Overflow-alternative,
  252.        routing-rerouting automatic repeat attempt , | Rec. Q.12.
  253.  
  254.        [5]          CCITT  Recommendation   Interruption   control   ,   |
  255.        Rec. Q.416.
  256.  
  257.  
  258.  
  259.        Recommendation Q.725
  260.  
  261.  
  262.  
  263.  
  264.  
  265.  
  266.  
  267.  
  268.  
  269.               SIGNALLING PERFORMANCE IN THE TELEPHONE APPLICATION
  270.  
  271.  
  272.  
  273.  
  274.        1       Introduction
  275.  
  276.  
  277.             This Recommendation gives the requirements  of  the  telephone
  278.        application of Signalling System No. 7.
  279.  
  280.             In Recommendation Q.706, the Message Transfer Part performance
  281.        is  described.  The Message Transfer Part is the basis of the tele-
  282.        phone application of Signalling System No. 7  and  provision  of  a
  283.        signalling network to serve the telephone service must take account
  284.        of the performance of the Message Transfer Part  and  the  require-
  285.        ments  of the telephone application. For example, taking account of
  286.        the message transfer times detailed in Recommendation Q.706 and the
  287.        requirements  for  message  transfer  times  between  two telephone
  288.        exchanges, a figure may be derived for the total permissible number
  289.        of signalling links in signalling relations in tandem for a partic-
  290.        ular call.
  291.  
  292.  
  293.        2       Unsuccessful calls due to signalling malfunction
  294.  
  295.  
  296.             The proportion of calls that are unsuccessful due  to  signal-
  297.        ling malfunction should be less than 1 in 105.
  298.  
  299.             By means of error detection (see Recommendation Q.703) as well
  300.        as  transmission  fault  indication  (see Recommendations G.732 [1]
  301.        and G.733  [2]), it is ensured that, overall,  not  more  than  one
  302.        error  in 108  of all signal units transmitted is accepted and will
  303.        cause false operation.
  304.  
  305.             Unsuccessful calls may be caused by undetected errors, loss of
  306.        messages  or  messages  delivered out of sequence (during emergency
  307.        situations within the signalling network) and may result in:
  308.  
  309.                -         incomplete call set-up,
  310.  
  311.                -          misrouted  calls  (e.g.  connection   of   wrong
  312.        numbers),
  313.  
  314.                -         calls routed correctly but mishandled (e.g. false
  315.        clearing).
  316.  
  317.  
  318.        3       Unavailability of a signalling route set
  319.  
  320.  
  321.             The overall unavailability of a signalling route  set  causing
  322.        the  unavailability  of  a  signalling relation should not exceed a
  323.        total of 10  minutes per year.
  324.  
  325.             Note  - The availability of a signalling route  set  within  a
  326.  
  327.  
  328.  
  329.  
  330.  
  331.  
  332.  
  333.  
  334.  
  335.        signalling  network  may  be  enhanced by replication of signalling
  336.        links, signalling paths and signalling routes.
  337.  
  338.  
  339.        4       Labelling potential
  340.  
  341.  
  342.             The label of the Telephone  User  Part  of  Signalling  System
  343.        No. 7  provides the potential to identify 16 | 84 signalling points
  344.        and up to 4096 speech circuits for each signalling relation.
  345.  
  346.  
  347.  
  348.        5       Cross-office transfer time
  349.  
  350.  
  351.  
  352.        5.1         Functional reference  points  and  transfer  time  com-
  353.        ponents
  354.  
  355.  
  356.  
  357.                                                         Figure 1/Q.725, p.
  358.  
  359.  
  360.  
  361.        5.2         Definitions
  362.  
  363.  
  364.                a)         cross-office transfer time, Tvcvu
  365.  
  366.                 Tc\duis the period which starts when the last bit  of  the
  367.        signal  unit leaves the incoming signalling data link and ends when
  368.        the last bit of the signal unit enters the outgoing signalling data
  369.        link for the first time. It also includes the queueing delay in the
  370.        absence of disturbances  but  not  the  additional  queueing  delay
  371.        caused by retransmission.
  372.  
  373.                b)         user handling time, Tvhvu
  374.  
  375.                 Th\duis the period which starts when the last bit  of  the
  376.        message  has entered the Telephone User Part and ends when the last
  377.        bit of the derived message has left the Telephone User Part.
  378.  
  379.  
  380.        5.3         Queueing delay
  381.  
  382.  
  383.             The  formulae  for  the  queueing  delays  are  described   in
  384.        Recommendation Q.706, S 4.2.
  385.  
  386.             The telephone traffic model assumed is given in Table 1/Q.725,
  387.        from  which  the  proportion  of signal messages may be obtained as
  388.        shown in Table 2/Q.725. Using Table 2/Q.725, examples  of  queueing
  389.        delays are calculated as shown in Figures 2/Q.725 to 5/Q.725, where
  390.        one call attempt per second per 64 kbit/s signalling data link  may
  391.        yield 0.00577  Erlang of the traffic loading of each channel.
  392.  
  393.  
  394.  
  395.  
  396.  
  397.  
  398.  
  399.  
  400.  
  401.        5.4         Estimates for message transfer time
  402.  
  403.  
  404.             The figures in Table 3/Q.725 are related to a  signalling  bit
  405.        rate of  64 kbit/s.
  406.  
  407.  
  408.        5.5         Effect of retransmission
  409.  
  410.  
  411.             As a consequence of correction  by  retransmission,  not  more
  412.        than  one  in   104 signals should be delayed more than 300 ms as a
  413.        long-term average. This requirement refers to each signalling link.
  414.  
  415.             This requirement is laid down in order to ensure  satisfactory
  416.        answer   delays.
  417.  
  418.  
  419.                                    H.T. [T10]
  420.                                   TABLE 1/Q.725
  421.                                  Traffic model
  422.  
  423.                    __________________________________________
  424.                     Sending procedure   "En bloc"   Overlap
  425.                    __________________________________________
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  477.        _______________________________________________________________________
  478.         Type of call      AW     SB    CC    AB   AW    SB   CC    AB
  479.        _______________________________________________________________________
  480.         Percent calls     30     10     5    5    30    10    5    5
  481.        _______________________________________________________________________
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  558.                         Others   112   3,5   2    3     0    3,5   2  3    2
  559.        _______________________________________________________________________
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  746.                               |
  747.                               |
  748.                               |
  749.                               |
  750.                               |
  751.                               |
  752.                               |
  753.                               |
  754.                               |
  755.                               |
  756.                               |
  757.                               |
  758.                               |
  759.                               |
  760.                               |
  761.                               |
  762.                               |
  763.                               |
  764.                               |
  765.                               |
  766.                               |
  767.                               |
  768.                               |
  769.                               |
  770.                               |
  771.                               |
  772.                               |
  773.                               |
  774.                               |
  775.                               |
  776.                               |
  777.  
  778.  
  779.  
  780.  
  781.  
  782.  
  783.  
  784.  
  785.  
  786.  
  787.  
  788.  
  789.  
  790.  
  791.  
  792.  
  793.  
  794.  
  795.  
  796.  
  797.  
  798.  
  799.  
  800.  
  801.  
  802.  
  803.  
  804.  
  805.  
  806.  
  807.  
  808.  
  809.  
  810.  
  811.  
  812.  
  813.  
  814.  
  815.  
  816.  
  817.  
  818.  
  819.                                      |
  820.                                      |
  821.                                      |
  822.                                      |
  823.                                      |
  824.                                      |
  825.                                      |
  826.                                      |
  827.                                      |
  828.                                      |
  829.                                      |
  830.                                      |
  831.                                      |
  832.                                      |
  833.                                      |
  834.                                      |
  835.                                      |
  836.                                      |
  837.                                      |
  838.                                      |
  839.                                      |
  840.                                      |
  841.                                      |
  842.                                      |
  843.                                      |
  844.                                      |
  845.                                      |
  846.                                      |
  847.                                      |
  848.                                      |
  849.                                      |
  850.                                      |
  851.                                      |
  852.                                      |
  853.                                      |
  854.                                      |
  855.                                      |
  856.                                      |
  857.                                      |
  858.                                      |
  859.                                      |
  860.                                      |
  861.                                      |
  862.                                      |
  863.  
  864.  
  865.  
  866.  
  867.  
  868.  
  869.  
  870.  
  871.  
  872.  
  873.  
  874.  
  875.  
  876.  
  877.  
  878.  
  879.  
  880.  
  881.  
  882.  
  883.  
  884.  
  885.  
  886.  
  887.  
  888.  
  889.  
  890.  
  891.  
  892.  
  893.  
  894.  
  895.  
  896.  
  897.  
  898.  
  899.  
  900.  
  901.  
  902.  
  903.  
  904.  
  905.                                            |
  906.                                            |
  907.                                            |
  908.                                            |
  909.                                            |
  910.                                            |
  911.                                            |
  912.                                            |
  913.                                            |
  914.                                            |
  915.                                            |
  916.                                            |
  917.                                            |
  918.                                            |
  919.                                            |
  920.                                            |
  921.                                            |
  922.                                            |
  923.                                            |
  924.                                            |
  925.                                            |
  926.                                            |
  927.                                            |
  928.                                            |
  929.                                            |
  930.                                            |
  931.                                            |
  932.                                            |
  933.                                            |
  934.                                            |
  935.                                            |
  936.                                            |
  937.                                            |
  938.                                            |
  939.                                            |
  940.                                            |
  941.                                            |
  942.                                            |
  943.                                            |
  944.                                            |
  945.                                            |
  946.                                            |
  947.                                            |
  948.                                            |
  949.  
  950.  
  951.  
  952.  
  953.  
  954.  
  955.  
  956.  
  957.  
  958.  
  959.  
  960.  
  961.  
  962.  
  963.  
  964.  
  965.  
  966.  
  967.  
  968.  
  969.  
  970.  
  971.  
  972.  
  973.  
  974.  
  975.  
  976.  
  977.  
  978.  
  979.  
  980.  
  981.  
  982.  
  983.  
  984.  
  985.  
  986.  
  987.  
  988.  
  989.  
  990.  
  991.                                                 |
  992.                                                 |
  993.                                                 |
  994.                                                 |
  995.                                                 |
  996.                                                 |
  997.                                                 |
  998.                                                 |
  999.                                                 |
  1000.                                                 |
  1001.                                                 |
  1002.                                                 |
  1003.                                                 |
  1004.                                                 |
  1005.                                                 |
  1006.                                                 |
  1007.                                                 |
  1008.                                                 |
  1009.                                                 |
  1010.                                                 |
  1011.                                                 |
  1012.                                                 |
  1013.                                                 |
  1014.                                                 |
  1015.                                                 |
  1016.                                                 |
  1017.                                                 |
  1018.                                                 |
  1019.                                                 |
  1020.                                                 |
  1021.                                                 |
  1022.                                                 |
  1023.                                                 |
  1024.                                                 |
  1025.                                                 |
  1026.                                                 |
  1027.                                                 |
  1028.                                                 |
  1029.                                                 |
  1030.                                                 |
  1031.                                                 |
  1032.                                                 |
  1033.                                                 |
  1034.                                                 |
  1035.  
  1036.  
  1037.  
  1038.  
  1039.  
  1040.  
  1041.  
  1042.  
  1043.  
  1044.  
  1045.  
  1046.  
  1047.  
  1048.  
  1049.  
  1050.  
  1051.  
  1052.  
  1053.  
  1054.  
  1055.  
  1056.  
  1057.  
  1058.  
  1059.  
  1060.  
  1061.  
  1062.  
  1063.  
  1064.  
  1065.  
  1066.  
  1067.  
  1068.  
  1069.  
  1070.  
  1071.  
  1072.  
  1073.  
  1074.  
  1075.  
  1076.  
  1077.                                                      |
  1078.                                                      |
  1079.                                                      |
  1080.                                                      |
  1081.                                                      |
  1082.                                                      |
  1083.                                                      |
  1084.                                                      |
  1085.                                                      |
  1086.                                                      |
  1087.                                                      |
  1088.                                                      |
  1089.                                                      |
  1090.                                                      |
  1091.                                                      |
  1092.                                                      |
  1093.                                                      |
  1094.                                                      |
  1095.                                                      |
  1096.                                                      |
  1097.                                                      |
  1098.                                                      |
  1099.                                                      |
  1100.                                                      |
  1101.                                                      |
  1102.                                                      |
  1103.                                                      |
  1104.                                                      |
  1105.                                                      |
  1106.                                                      |
  1107.                                                      |
  1108.                                                      |
  1109.                                                      |
  1110.                                                      |
  1111.                                                      |
  1112.                                                      |
  1113.                                                      |
  1114.                                                      |
  1115.                                                      |
  1116.                                                      |
  1117.                                                      |
  1118.                                                      |
  1119.                                                      |
  1120.                                                      |
  1121.  
  1122.  
  1123.  
  1124.  
  1125.  
  1126.  
  1127.  
  1128.  
  1129.  
  1130.  
  1131.  
  1132.  
  1133.  
  1134.  
  1135.  
  1136.  
  1137.  
  1138.  
  1139.  
  1140.  
  1141.  
  1142.  
  1143.  
  1144.  
  1145.  
  1146.  
  1147.  
  1148.  
  1149.  
  1150.  
  1151.  
  1152.  
  1153.  
  1154.  
  1155.  
  1156.  
  1157.  
  1158.  
  1159.  
  1160.  
  1161.  
  1162.  
  1163.                                                           |
  1164.                                                           |
  1165.                                                           |
  1166.                                                           |
  1167.                                                           |
  1168.                                                           |
  1169.                                                           |
  1170.                                                           |
  1171.                                                           |
  1172.                                                           |
  1173.                                                           |
  1174.                                                           |
  1175.                                                           |
  1176.                                                           |
  1177.                                                           |
  1178.                                                           |
  1179.                                                           |
  1180.                                                           |
  1181.                                                           |
  1182.                                                           |
  1183.                                                           |
  1184.                                                           |
  1185.                                                           |
  1186.                                                           |
  1187.                                                           |
  1188.                                                           |
  1189.                                                           |
  1190.                                                           |
  1191.                                                           |
  1192.                                                           |
  1193.                                                           |
  1194.                                                           |
  1195.                                                           |
  1196.                                                           |
  1197.                                                           |
  1198.                                                           |
  1199.                                                           |
  1200.                                                           |
  1201.                                                           |
  1202.                                                           |
  1203.                                                           |
  1204.                                                           |
  1205.                                                           |
  1206.                                                           |
  1207.  
  1208.  
  1209.  
  1210.  
  1211.  
  1212.  
  1213.  
  1214.  
  1215.  
  1216.  
  1217.  
  1218.  
  1219.  
  1220.  
  1221.  
  1222.  
  1223.  
  1224.  
  1225.  
  1226.  
  1227.  
  1228.  
  1229.  
  1230.  
  1231.  
  1232.  
  1233.  
  1234.  
  1235.  
  1236.  
  1237.  
  1238.  
  1239.  
  1240.  
  1241.  
  1242.  
  1243.  
  1244.  
  1245.  
  1246.  
  1247.  
  1248.  
  1249.                                                                 |
  1250.                                                                 |
  1251.                                                                 |
  1252.                                                                 |
  1253.                                                                 |
  1254.                                                                 |
  1255.                                                                 |
  1256.                                                                 |
  1257.                                                                 |
  1258.                                                                 |
  1259.                                                                 |
  1260.                                                                 |
  1261.                                                                 |
  1262.                                                                 |
  1263.                                                                 |
  1264.                                                                 |
  1265.                                                                 |
  1266.                                                                 |
  1267.                                                                 |
  1268.                                                                 |
  1269.                                                                 |
  1270.                                                                 |
  1271.                                                                 |
  1272.                                                                 |
  1273.                                                                 |
  1274.                                                                 |
  1275.                                                                 |
  1276.                                                                 |
  1277.                                                                 |
  1278.                                                                 |
  1279.                                                                 |
  1280.                                                                 |
  1281.                                                                 |
  1282.                                                                 |
  1283.                                                                 |
  1284.                                                                 |
  1285.                                                                 |
  1286.                                                                 |
  1287.                                                                 |
  1288.                                                                 |
  1289.                                                                 |
  1290.                                                                 |
  1291.                                                                 |
  1292.                                                                 |
  1293.  
  1294.  
  1295.  
  1296.  
  1297.  
  1298.  
  1299.  
  1300.  
  1301.  
  1302.  
  1303.  
  1304.  
  1305.  
  1306.  
  1307.  
  1308.  
  1309.  
  1310.  
  1311.  
  1312.  
  1313.  
  1314.  
  1315.  
  1316.  
  1317.  
  1318.  
  1319.  
  1320.  
  1321.  
  1322.  
  1323.  
  1324.  
  1325.  
  1326.  
  1327.  
  1328.  
  1329.  
  1330.  
  1331.  
  1332.  
  1333.  
  1334.  
  1335.                                                                     |
  1336.                                                                     |
  1337.                                                                     |
  1338.                                                                     |
  1339.                                                                     |
  1340.                                                                     |
  1341.                                                                     |
  1342.                                                                     |
  1343.                                                                     |
  1344.                                                                     |
  1345.                                                                     |
  1346.                                                                     |
  1347.                                                                     |
  1348.                                                                     |
  1349.                                                                     |
  1350.                                                                     |
  1351.                                                                     |
  1352.                                                                     |
  1353.                                                                     |
  1354.                                                                     |
  1355.                                                                     |
  1356.                                                                     |
  1357.                                                                     |
  1358.                                                                     |
  1359.                                                                     |
  1360.                                                                     |
  1361.                                                                     |
  1362.                                                                     |
  1363.                                                                     |
  1364.                                                                     |
  1365.                                                                     |
  1366.                                                                     |
  1367.                                                                     |
  1368.                                                                     |
  1369.                                                                     |
  1370.                                                                     |
  1371.                                                                     |
  1372.                                                                     |
  1373.                                                                     |
  1374.                                                                     |
  1375.                                                                     |
  1376.  
  1377.  
  1378.  
  1379.  
  1380.  
  1381.  
  1382.  
  1383.  
  1384.  
  1385.  
  1386.  
  1387.  
  1388.  
  1389.  
  1390.  
  1391.  
  1392.  
  1393.  
  1394.  
  1395.  
  1396.  
  1397.  
  1398.  
  1399.  
  1400.  
  1401.  
  1402.  
  1403.  
  1404.  
  1405.  
  1406.  
  1407.  
  1408.  
  1409.  
  1410.  
  1411.  
  1412.  
  1413.  
  1414.  
  1415.                                                                          |
  1416.                                                                          |
  1417.                                                                          |
  1418.                                                                          |
  1419.                                                                          |
  1420.                                                                          |
  1421.                                                                          |
  1422.                                                                          |
  1423.                                                                          |
  1424.                                                                          |
  1425.                                                                          |
  1426.                                                                          |
  1427.                                                                          |
  1428.                                                                          |
  1429.                                                                          |
  1430.                                                                          |
  1431.                                                                          |
  1432.                                                                          |
  1433.                                                                          |
  1434.                                                                          |
  1435.                                                                          |
  1436.                                                                          |
  1437.                                                                          |
  1438.                                                                          |
  1439.                                                                          |
  1440.                                                                          |
  1441.                                                                          |
  1442.                                                                          |
  1443.                                                                          |
  1444.                                                                          |
  1445.                                                                          |
  1446.                                                                          |
  1447.                                                                          |
  1448.                                                                          |
  1449.                                                                          |
  1450.                                                                          |
  1451.                                                                          |
  1452.                                                                          |
  1453.                                                                          |
  1454.                                                                          |
  1455.                                                                          |
  1456.  
  1457.  
  1458.  
  1459.  
  1460.  
  1461.  
  1462.  
  1463.  
  1464.  
  1465.  
  1466.  
  1467.  
  1468.  
  1469.  
  1470.  
  1471.  
  1472.  
  1473.  
  1474.  
  1475.  
  1476.  
  1477.  
  1478.  
  1479.  
  1480.  
  1481.  
  1482.  
  1483.  
  1484.  
  1485.  
  1486.  
  1487.  
  1488.  
  1489.  
  1490.  
  1491.  
  1492.  
  1493.  
  1494.  
  1495.                                                                              |
  1496.                                                                              |
  1497.                                                                              |
  1498.                                                                              |
  1499.                                                                              |
  1500.                                                                              |
  1501.                                                                              |
  1502.                                                                              |
  1503.                                                                              |
  1504.                                                                              |
  1505.                                                                              |
  1506.                                                                              |
  1507.                                                                              |
  1508.                                                                              |
  1509.                                                                              |
  1510.                                                                              |
  1511.                                                                              |
  1512.                                                                              |
  1513.                                                                              |
  1514.                                                                              |
  1515.                                                                              |
  1516.                                                                              |
  1517.                                                                              |
  1518.                                                                              |
  1519.                                                                              |
  1520.                                                                              |
  1521.                                                                              |
  1522.                                                                              |
  1523.                                                                              |
  1524.                                                                              |
  1525.                                                                              |
  1526.                                                                              |
  1527.                                                                              |
  1528.                                                                              |
  1529.                                                                              |
  1530.                                                                              |
  1531.                                                                              |
  1532.                                                                              |
  1533.                                                                              |
  1534.                                                                              |
  1535.                                                                              |
  1536.                                                                              |
  1537.                                                                              |
  1538.                                                                              |
  1539.  
  1540.  
  1541.  
  1542.  
  1543.  
  1544.  
  1545.  
  1546.  
  1547.  
  1548.  
  1549.  
  1550.  
  1551.  
  1552.  
  1553.  
  1554.  
  1555.  
  1556.  
  1557.  
  1558.  
  1559.  
  1560.  
  1561.  
  1562.  
  1563.  
  1564.  
  1565.  
  1566.  
  1567.  
  1568.  
  1569.  
  1570.  
  1571.  
  1572.  
  1573.  
  1574.  
  1575.  
  1576.  
  1577.  
  1578.  
  1579.  
  1580.  
  1581.  
  1582.  
  1583.  
  1584.        AW Answered SB Subscriber busy and not answered CC Circuit  conges-
  1585.        tion AB Abortive
  1586.  
  1587.        Note -  The assumptions used in this model are chosen for illustra-
  1588.        tive purposes, and should not be considered to be typical.
  1589.                                            Tableau 1/Q.725 [T1.725], p. 37
  1590.  
  1591.  
  1592.  
  1593.        Blanc
  1594.  
  1595.  
  1596.  
  1597.  
  1598.  
  1599.  
  1600.  
  1601.  
  1602.  
  1603.                                  H.T. [T2.725]
  1604.                                   TABLE 2/Q.725
  1605.                              Proportion of messages
  1606.  
  1607.        ___________________________________________________________________________
  1608.         Length (bits)              176         152   128    112    104     Total
  1609.        ___________________________________________________________________________
  1610.          {
  1611.         Messages per call
  1612.         in both directions
  1613.          }                        0.45         0.5   0.45    2.0    2.9      6.3
  1614.        ___________________________________________________________________________
  1615.         Percent                   7.1       |
  1616.                                             |
  1617.                                             |
  1618.                                             |
  1619.                                             |
  1620.                                             |
  1621.                                             |
  1622.                                             |
  1623.  
  1624.  
  1625.  
  1626.  
  1627.  
  1628.  
  1629.                                                7.9|
  1630.                                                   |
  1631.                                                   |
  1632.                                                   |
  1633.                                                   |
  1634.                                                   |
  1635.                                                   |
  1636.                                                   |
  1637.  
  1638.  
  1639.  
  1640.  
  1641.  
  1642.  
  1643.                                                      7.1 |
  1644.                                                          |
  1645.                                                          |
  1646.                                                          |
  1647.                                                          |
  1648.                                                          |
  1649.                                                          |
  1650.                                                          |
  1651.  
  1652.  
  1653.  
  1654.  
  1655.  
  1656.  
  1657.                                                             31.7|
  1658.                                                                 |
  1659.                                                                 |
  1660.                                                                 |
  1661.                                                                 |
  1662.                                                                 |
  1663.                                                                 |
  1664.                                                                 |
  1665.  
  1666.  
  1667.  
  1668.  
  1669.  
  1670.  
  1671.                                                                    46.0
  1672.  
  1673.                                                                        |
  1674.                                                                        |
  1675.                                                                        |
  1676.                                                                        |
  1677.                                                                        |
  1678.                                                                        |
  1679.                                                                        |
  1680.                                                                        |
  1681.  
  1682.  
  1683.  
  1684.  
  1685.  
  1686.  
  1687.                                                                           100 |
  1688.        ___________________________________________________________________________
  1689.          {
  1690.         Mean message
  1691.         length (T
  1692.         m
  1693.         )
  1694.          }                   117.2 bits
  1695.        ___________________________________________________________________________
  1696.         k 1                  1.032
  1697.        ___________________________________________________________________________
  1698.         k 2                  1.107
  1699.        ___________________________________________________________________________
  1700.         k 3                  1.239
  1701.        ___________________________________________________________________________
  1702.  
  1703.       |
  1704.       |
  1705.       |
  1706.       |
  1707.       |
  1708.       |
  1709.       |
  1710.       |
  1711.       |
  1712.       |
  1713.       |
  1714.       |
  1715.       |
  1716.       |
  1717.       |
  1718.       |
  1719.       |
  1720.       |
  1721.       |
  1722.       |
  1723.       |
  1724.       |
  1725.  
  1726.  
  1727.  
  1728.  
  1729.  
  1730.  
  1731.  
  1732.  
  1733.  
  1734.  
  1735.  
  1736.  
  1737.  
  1738.  
  1739.  
  1740.  
  1741.  
  1742.  
  1743.  
  1744.  
  1745.                           |
  1746.                           |
  1747.                           |
  1748.                           |
  1749.                           |
  1750.                           |
  1751.                           |
  1752.                           |
  1753.                           |
  1754.                           |
  1755.                           |
  1756.                           |
  1757.                           |
  1758.                           |
  1759.                           |
  1760.                           |
  1761.                           |
  1762.                           |
  1763.                           |
  1764.                           |
  1765.                           |
  1766.                           |
  1767.  
  1768.  
  1769.  
  1770.  
  1771.  
  1772.  
  1773.  
  1774.  
  1775.  
  1776.  
  1777.  
  1778.  
  1779.  
  1780.  
  1781.  
  1782.  
  1783.  
  1784.  
  1785.  
  1786.  
  1787.                                                                                  |
  1788.                                                                                  |
  1789.                                                                                  |
  1790.                                                                                  |
  1791.                                                                                  |
  1792.                                                                                  |
  1793.                                                                                  |
  1794.                                                                                  |
  1795.                                                                                  |
  1796.                                                                                  |
  1797.                                                                                  |
  1798.                                                                                  |
  1799.                                                                                  |
  1800.                                                                                  |
  1801.                                                                                  |
  1802.                                                                                  |
  1803.                                                                                  |
  1804.                                                                                  |
  1805.                                                                                  |
  1806.                                                                                  |
  1807.                                                                                  |
  1808.                                                                                  |
  1809.  
  1810.  
  1811.  
  1812.  
  1813.  
  1814.  
  1815.  
  1816.  
  1817.  
  1818.  
  1819.  
  1820.  
  1821.  
  1822.  
  1823.  
  1824.  
  1825.  
  1826.  
  1827.  
  1828.  
  1829.  
  1830.  
  1831.                                            Tableau 2/Q.725 [T2.725], p. 38
  1832.  
  1833.  
  1834.  
  1835.                                                      Figure 2/Q.725, p. 39
  1836.  
  1837.  
  1838.  
  1839.  
  1840.  
  1841.                                                      Figure 3/Q.725, p. 40
  1842.  
  1843.  
  1844.  
  1845.  
  1846.  
  1847.                                                      Figure 4/Q.725, p. 41
  1848.  
  1849.  
  1850.  
  1851.                                                      Figure 5/Q.725, p. 42
  1852.  
  1853.  
  1854.  
  1855.                                  H.T. [T3.725]
  1856.                                   TABLE 3/Q.725
  1857.        lw(60p) | lw(60p) | lw(30p) | lw(30p) .
  1858.  
  1859.                                            Tableau 3/Q.725 [T3.725], p. 43
  1860.  
  1861.  
  1862.  
  1863.  
  1864.  
  1865.  
  1866.  
  1867.  
  1868.  
  1869.                References
  1870.  
  1871.  
  1872.        [1]         CCITT Recommendation  Characteristics  of  primary  PCM
  1873.        multiplex equipment operating at 2048 kbit/s , | Rec. G.732.
  1874.  
  1875.        [2]         CCITT Recommendation  Characteristics  of  primary  PCM
  1876.        multiplex equipment operating at 1544 kbit/s , | Rec. G.733.
  1877.  
  1878.  
  1879.        Blanc
  1880.  
  1881.  
  1882.  
  1883.        MONTAGE:  PAGE PAIRE = PAGE BLANCHE
  1884.  
  1885.  
  1886.  
  1887.  
  1888.  
  1889.  
  1890.  
  1891.  
  1892.                                     SECTION 2
  1893.  
  1894.                           ISDN SUPPLEMENTARY SERVICES
  1895.  
  1896.  
  1897.  
  1898.        Recommendation Q.730
  1899.  
  1900.  
  1901.                           ISDN SUPPLEMENTARY SERVICES
  1902.  
  1903.  
  1904.  
  1905.  
  1906.        1       General
  1907.  
  1908.  
  1909.             1.1 This Recommendation describes  the  signalling  procedures
  1910.        for  Supplementary Services to be used in conjunction with the ISDN
  1911.        User Part defined in Recommendations Q.761-764, Q.766 and the Tran-
  1912.        saction   Capabilities   Applications   Part   (TCAP)   defined  in
  1913.        Recommendations Q.771-774.
  1914.  
  1915.  
  1916.             Each Supplementary Service has been defined in  separate  sec-
  1917.        tions each containing the complete procedures encompassing both the
  1918.        ISDN User Part and the procedures to be used on  the  top  of  TCAP
  1919.        where appropriate.
  1920.  
  1921.             Each section contains a general paragraph  giving  details  of
  1922.        the specific service with references to the Stage I and II descrip-
  1923.        tions defined in the relevant  Recommendations  of  the  I.200  and
  1924.        Q.80 Series. The call set-up
  1925.  
  1926.             procedures   and   the   actions    taken    at    originating
  1927.        exchanges, etc.  are  defined.   Arrow diagrams showing the message
  1928.        flows for both successful and  unsuccessful  establishment  of  the
  1929.  
  1930.  
  1931.  
  1932.  
  1933.  
  1934.  
  1935.  
  1936.  
  1937.  
  1938.        service are generally included. The formats and codings aspects are
  1939.        not defined in this Recommendation but references are made  to  the
  1940.        appropriate ISDN User Part, TC or SCCP Recommendations.
  1941.  
  1942.  
  1943.        1.2         Information request/response
  1944.  
  1945.  
  1946.             The   "information   request/response"   message   interchange
  1947.        described  in the calling line identity supplementary services uses
  1948.        a general request/response mechanism (e.g. INR/INF messages)  which
  1949.        can  be used in the future for supplementary services not currently
  1950.        defined (see Recommendation Q.764).
  1951.  
  1952.  
  1953.        1.3         Exceeding the maximum message length  (e.g.  ISDN  User
  1954.        Part 272 octets)
  1955.  
  1956.  
  1957.             If for any reason the combination of basic plus  supplementary
  1958.        service  information  causes the overall maximum length of the mes-
  1959.        sage  (e.g. Initial  Address  Message)  to  be  exceeded  then  the
  1960.        user-to-user   supplementary  service 1,  if  included,  should  be
  1961.        rejected (see S 2 covering interactions).
  1962.  
  1963.             The combination of other services which may cause the  message
  1964.        length  to  be  exceeded  will  depend  on  the  call state and the
  1965.        requested service.
  1966.  
  1967.  
  1968.        1.4         Layout of Recommendation Q.730
  1969.  
  1970.  
  1971.                S 1         General
  1972.  
  1973.                S 2         User-to-user signalling (Note)
  1974.  
  1975.                S 3         Close user group
  1976.  
  1977.                S 4         Calling line identification  (presentation  and
  1978.        restriction)
  1979.  
  1980.                S 5         Direct dialling in
  1981.  
  1982.                S 6         Call forwarding (Note)
  1983.  
  1984.                S  7          Time-out  table  for  supplementary  services
  1985.        (requires further study)
  1986.  
  1987.             Note   - The  text  for  the  explicit   invocation   of   the
  1988.        user-to-user signalling has been included as Annex A.
  1989.  
  1990.  
  1991.  
  1992.        2       User-to-user signalling service
  1993.  
  1994.  
  1995.  
  1996.  
  1997.  
  1998.  
  1999.  
  2000.  
  2001.  
  2002.  
  2003.  
  2004.        2.1         General description of user-to-user service
  2005.  
  2006.  
  2007.             The   user-to-user   signalling    supplementary    service(s)
  2008.        provide(s)  a means of communication between two users by using the
  2009.        ISDN  User  Part  or  SCCP  protocols  defined  in  Recommendations
  2010.        Q.711-714  and  Q.761-764,  766.  In  order  for the services to be
  2011.        usable, they also have to be provided in the access protocol.
  2012.  
  2013.             User-to-user signalling is used to exchange I.257  information
  2014.        between two users to provide the user-to-user services described in
  2015.        Recommendation  I.257.  This  section  is  specific  to  Signalling
  2016.        System No. 7.   The  general  description  for  services 1-3 may be
  2017.        found in the  last  mentioned  Recommendation  and  the  functional
  2018.        description in Recommendation Q.87.
  2019.  
  2020.  
  2021.        2.1.1         User-to-user services
  2022.  
  2023.  
  2024.             Three  user-to-user  signalling   services   associated   with
  2025.        circuit-switched  calls  that  may be provided by the network users
  2026.        are:
  2027.  
  2028.                Service 1:  user-to-user signalling  exchanged  during  the
  2029.        set-up  and  clearing  phases of a call, within ISDN User Part call
  2030.        set-up and release messages as defined in Recommendation Q.763;
  2031.  
  2032.                Service 2:  user-to-user signalling exchanged  during  call
  2033.        set-up  between  the address complete or call progress messages and
  2034.        the answer or connect  messages,  within  user-to-user  information
  2035.        messages; and
  2036.  
  2037.                Service 3:  user-to-user signalling exchanged while a  call
  2038.        is in the active state, within user-to-user information messages.
  2039.  
  2040.             All three services may be used separately or in  any  combina-
  2041.        tion  within  a single call. As an option at call set-up, users may
  2042.        be able to specify whether the  requested  user-to-user  signalling
  2043.        service(s)  is(are)  essential  or non-essential for the call (i.e.
  2044.        whether the call should be completed or not if user-to-user  infor-
  2045.        mation  cannot be passed). Up to 128 octets of user information may
  2046.        be transferred in a message in each of the three services  informa-
  2047.        tion  parameter  name, the protocol control indicator or the length
  2048.        octets.
  2049.  
  2050.  
  2051.        2.1.2         Service request
  2052.  
  2053.  
  2054.        _________________________
  2055.        During an interim period of time, networks may  support
  2056.        a  lesser  number (e.g. 32 octets) due to protocol res-
  2057.        trictions; 32 octets will always be supported. Restric-
  2058.        tions may apply to calls requesting user-to-user infor-
  2059.        mation more than 32 octets.
  2060.  
  2061.  
  2062.  
  2063.  
  2064.  
  2065.  
  2066.  
  2067.  
  2068.  
  2069.  
  2070.             Service 1 may be requested implicitly by the presence  of  the
  2071.        user-to-user  information parameter in the Initial Address Message.
  2072.        An implicit request is "non-essential" by default.
  2073.  
  2074.             Explicit requests of Service 1 and 2 must be  in  the  Initial
  2075.        Address  Message. Service 3 may be explicitly requested in the Ini-
  2076.        tial Address Message during call set-up. When there is an  explicit
  2077.        request  a  single  user-to-user  indicators parameter will be used
  2078.        with one of the following indications for each of  the  three  ser-
  2079.        vices:
  2080.  
  2081.                -         no information;
  2082.  
  2083.                -         requested, non-essential;
  2084.  
  2085.                -         requested, essential.
  2086.  
  2087.  
  2088.        2.1.3         Response (Confirmation)
  2089.  
  2090.  
  2091.             If explicit requests are used there  should,  in  general,  be
  2092.        explicit  responses in a user-to-user indicators parameter with one
  2093.        of the following indications for each of the three services:
  2094.  
  2095.                -         no information;
  2096.  
  2097.                -         provided;
  2098.  
  2099.                -         not provided.
  2100.  
  2101.  
  2102.             Implicit "not provided" responses occur when:
  2103.  
  2104.                -          Service 1 has been implicitly requested  and  no
  2105.        user-to-user information is received in call set-up or release mes-
  2106.        sages; or
  2107.  
  2108.                -          Service 1, 2 or 3 has been explicitly  requested
  2109.        and  there  is  no  indication of acceptance or rejection from call
  2110.        control.
  2111.  
  2112.  
  2113.        2.1.4         Flow control
  2114.  
  2115.  
  2116.             The exchange of user-to-user signalling  is  limited  by  flow
  2117.        control  procedures  provided  on  the access by either the user or
  2118.        network. The need for interexchange flow control procedures by  the
  2119.        ISDN User Part for user-to-user signalling should be evaluated.
  2120.  
  2121.  
  2122.        2.2         Procedures for user-to-user signalling associated  with
  2123.        circuit-switched call
  2124.  
  2125.  
  2126.             The following sections only specify the  signalling  procedure
  2127.  
  2128.  
  2129.  
  2130.  
  2131.  
  2132.  
  2133.  
  2134.  
  2135.  
  2136.        used  to  implicitly  invoke  the  Service 1. Signalling procedures
  2137.        defined to support the other services are specified in Annex A.
  2138.  
  2139.  
  2140.        2.2.1         User-to-user signalling, Service 1
  2141.  
  2142.  
  2143.  
  2144.        2.2.1.1         General characteristics
  2145.  
  2146.  
  2147.             Service 1 allows users to communicate with  user-to-user  sig-
  2148.        nalling  by  transferring user-to-user information within ISDN User
  2149.        Part messages during the  call  set-up  and  clearing  phases.  The
  2150.        user-to-user  signalling  service provided is not a guaranteed ser-
  2151.        vice. If for any reason the combination of the basic  plus  supple-
  2152.        mentary  service  information  causes the overall maximum length of
  2153.        the message to be exceeded then if the User-to-user Signalling Ser-
  2154.        vice 1 is included, then the service should be rejected.
  2155.  
  2156.  
  2157.        2.2.1.2         User-to-user signalling in the call set-up phase  -
  2158.        implicit service request
  2159.  
  2160.  
  2161.             Procedures for call set-up are as described in  Recommendation
  2162.        Q.764, S 2, with the following changes:
  2163.  
  2164.             Service 1 may be invoked by sending the user-to-user  informa-
  2165.        tion   parameter   of   variable   length   that  is  specified  in
  2166.        Recommendation Q.763, S 3.34 in an Initial Address Message that  is
  2167.        requested in a call set-up request from call control. This informa-
  2168.        tion parameter is transported  across  the  network  and  delivered
  2169.        unchanged  to the terminating call control for the called user. The
  2170.        user-to-user indicators parameter will not be sent.
  2171.  
  2172.             The reception of a user-to-user  information  parameter  in  a
  2173.        call set-up or release request from the terminating call control is
  2174.        an implicit indication of the acceptance of Service 1.
  2175.  
  2176.             The user or network may not  be  able  to  interpret  incoming
  2177.        user-to-user  information. In such situations, the user should dis-
  2178.        card this information without disrupting normal call  handling.  No
  2179.        specific  signalling is provided by the network to accommodate this
  2180.        situation.
  2181.  
  2182.  
  2183.        2.2.1.3         Interworking
  2184.  
  2185.  
  2186.             In the case of  interworking  with  a  non-ISDN  network,  the
  2187.        "interworking" protocol control information will be returned to the
  2188.        originating exchange in  the  first  appropriate  message,  e.g. an
  2189.        Address Complete Message. Two ISDN networks that interwork may have
  2190.        to retain knowledge of  the  service  request  until  it  is  clear
  2191.        whether both can support the service.
  2192.  
  2193.  
  2194.  
  2195.  
  2196.  
  2197.  
  2198.  
  2199.  
  2200.  
  2201.  
  2202.        2.2.1.4         Rejection of implicit service requests
  2203.  
  2204.  
  2205.             Networks that cannot provide the  service  requested  may  not
  2206.        return a rejection indication.
  2207.  
  2208.  
  2209.        2.2.1.5         User-to-user signalling in the call clearing phase
  2210.  
  2211.  
  2212.             A user-to-user information parameter may be  included  in  the
  2213.        Release Message. The user-to-user information parameter received at
  2214.        the distant exchange in the Release Message is passed to  the  call
  2215.        control  for  the remote user. In the case of simultaneous clearing
  2216.        of the call, the Release Message may not reach  the  distant  local
  2217.        exchange and the user-to-user information will be lost.
  2218.  
  2219.  
  2220.  
  2221.        2.2.1.6         Message flow diagrams
  2222.  
  2223.  
  2224.             The message flow diagrams are shown  in  Figure  1B/FQ.730  as
  2225.        well  as  the  use of user-to-user signalling service 1 when impli-
  2226.        citly requested in a point-to-point configuration.
  2227.  
  2228.             The messages shown with dashed lines are not part of the  ISDN
  2229.        User  Part  protocol  and  are  for  information only. For detailed
  2230.        information on the access protocol user-to-user procedures the ISDN
  2231.        access protocol Recommendation should be examined.
  2232.  
  2233.  
  2234.                                                      Figure 1/Q.730, p. 44
  2235.  
  2236.  
  2237.  
  2238.  
  2239.  
  2240.  
  2241.  
  2242.        2.2.2         Interaction with other supplementary services
  2243.  
  2244.  
  2245.  
  2246.        2.2.2.1         Call forwarding services
  2247.  
  2248.  
  2249.             Interactions with the call forwarding services  are  shown  in
  2250.        the call forwarding protocol sections.
  2251.  
  2252.  
  2253.        2.2.2.2         Call waiting service
  2254.  
  2255.  
  2256.             Interactions with the call waiting service are  shown  in  the
  2257.        call  waiting  protocol  sections.  (Call  waiting  is  for further
  2258.        study.)
  2259.  
  2260.  
  2261.  
  2262.  
  2263.  
  2264.  
  2265.  
  2266.  
  2267.  
  2268.        2.2.2.3         Other services
  2269.  
  2270.  
  2271.             There are no known interactions with services other than those
  2272.        listed.
  2273.  
  2274.  
  2275.        2.2.2.4         State transition diagrams
  2276.  
  2277.  
  2278.             The state transition diagrams may be found in Stage 2 descrip-
  2279.        tions of the user-to-user service.
  2280.  
  2281.  
  2282.        3       Closed user group (CUG)
  2283.  
  2284.  
  2285.  
  2286.        3.1         General
  2287.  
  2288.  
  2289.             The closed user group (CUG) supplementary  service  enables  a
  2290.        group  of  users  to  intercommunicate only among themselves or, as
  2291.        required, one or more users may be provided with  incoming/outgoing
  2292.        access to users outside the group.
  2293.  
  2294.             The stage  I  definition  of  the  CUG  service  is  given  in
  2295.        Recommendation I.255, and its stage II service definition including
  2296.        network functions are given in Recommendation Q.85.
  2297.  
  2298.             The realization of the CUG facilities is done by the provision
  2299.        of  interlock  codes  and  is based on various validation checks as
  2300.        defined in Q.85 at  call  set-up,  determining  whether  or  not  a
  2301.        requested  call to or from a user having a CUG facility is allowed.
  2302.        In particular, a validation check is performed  by  verifying  that
  2303.        both  the calling and called parties belong to the CUG indicated by
  2304.        the interlock code.
  2305.  
  2306.             The data for each CUG that a user belongs  to  can  either  be
  2307.        stored at the local exchange to which the user is connected (decen-
  2308.        tralized administration of CUG data), or at dedicated  point(s)  in
  2309.        the network (centralized administration of CUG data).
  2310.  
  2311.             In S 3.2 the call  set-up  procedure  based  on  decentralized
  2312.        administration of CUG data is specified making use of the ISDN User
  2313.        Part as defined in Recommendations Q.761-764 and Q.766.
  2314.  
  2315.             In S 3.3  the  call  set-up  procedure  based  on  centralized
  2316.        administration of CUG data is specified making use of the ISDN User
  2317.        Part as defined in  Recommendations Q.761-764  and  Q.766  and  the
  2318.        Transaction  Capabilities  Application  Part  (TCAP)  as defined in
  2319.        Recommendations Q.771-775.
  2320.  
  2321.             Section 3.4 specifies the application service  element  (ASE),
  2322.        situated   above  the  Transaction  Capabilities  Application  Part
  2323.        (TCAP), and used for CUG validation check with centralized adminis-
  2324.        tration of CUG data.
  2325.  
  2326.  
  2327.  
  2328.  
  2329.  
  2330.  
  2331.  
  2332.  
  2333.  
  2334.        3.2         Call set-up procedure with decentralized administration
  2335.        of CUG data
  2336.  
  2337.  
  2338.  
  2339.        3.2.1         Originating exchange
  2340.  
  2341.  
  2342.             The actions at the originating exchange at call set-up from  a
  2343.        user  belonging  to  a  CUG  depend on the result of the validation
  2344.        checks performed there based on whether the user belongs to one  or
  2345.        more CUGs and on the combination of CUG facilities that applies.
  2346.  
  2347.  
  2348.                a)         CUG call without outgoing access
  2349.  
  2350.                If the result of the validation check  indicates  that  the
  2351.        call  should be dealt with as a CUG call, the interlock code of the
  2352.        selected CUG is obtained. The initial address message forwarded  to
  2353.        the next exchange then includes the interlock code together with an
  2354.        indication that the call is a CUG call without outgoing access. The
  2355.        ISUP  preference indicator of the forward call indicators parameter
  2356.        in the IAM is set to "ISUP required all the way".
  2357.  
  2358.                b)         CUG call with outgoing access
  2359.  
  2360.                If the result of the validation check  indicates  that  the
  2361.        call  should  be dealt with as a CUG call with outgoing access, the
  2362.        interlock code of the selected CUG together with an outgoing access
  2363.        indication  is  obtained.  The initial address message forwarded to
  2364.        the next exchange then includes the interlock code together with an
  2365.        indication that the call is a CUG call for which outgoing access is
  2366.        allowed. The ISUP preference indicator of the forward call  indica-
  2367.        tors  parameter  in the IAM is set to "ISUP preferred all the way",
  2368.        unless another service requires a more stringent setting.
  2369.  
  2370.                c)         Non-CUG call
  2371.  
  2372.                If the result of the validation check  indicates  that  the
  2373.        call  should  be  dealt with as a non-CUG call, the initial address
  2374.        message forwarded to the next exchange then  does  not  include  an
  2375.        interlock code nor a CUG call indication.
  2376.  
  2377.                d)         Call rejected
  2378.  
  2379.                If the result of the validation check  indicates  that  the
  2380.        call is to be rejected, the call set-up is not initiated.
  2381.  
  2382.  
  2383.        3.2.2         Transit exchange
  2384.  
  2385.  
  2386.             With the possible exception of some  gateway  exchanges,  each
  2387.        transit exchange sets up a CUG call as an ordinary call. The infor-
  2388.        mation related to the CUG facilities received  from  the  preceding
  2389.        exchange,  i.e. an interlock code, a CUG call indication - possibly
  2390.        with an indication that outgoing access is allowed -  is  forwarded
  2391.  
  2392.  
  2393.  
  2394.  
  2395.  
  2396.  
  2397.  
  2398.  
  2399.  
  2400.        to the succeeding exchange.
  2401.  
  2402.             In the case of an international CUG call, no special functions
  2403.        are  required  at  the  gateway exchange provided that the interna-
  2404.        tional interlock code assigned to the international  CUG  concerned
  2405.        is  used  in  the  national  network.  However, in the case where a
  2406.        national interlock code other  than  the  applicable  international
  2407.        interlock  code  is  used within a national network, interlock code
  2408.        conversion is required at the gateway (or corresponding) exchange.
  2409.  
  2410.             In case of interworking with a network which does not  support
  2411.        the  CUG  facility,  the  gateway  exchange  may  release the call,
  2412.        depending on the contents of the CUG call indicator in the received
  2413.        IAM. The action at the gateway exchange, in this case, is indicated
  2414.        in Table 1/Q.730. In cases where a call is rejected as  the  result
  2415.        of  the interworking, a release message including the cause parame-
  2416.        ter indicating ## 88 is sent towards the originating exchange.
  2417.  
  2418.  
  2419.        3.2.3         Destination exchange
  2420.  
  2421.  
  2422.             At the destination exchange a validation check of the accepta-
  2423.        bility  of  a  call  is made according to the rule specified in the
  2424.        Recommendation Q.85 where either the calling party (as indicated by
  2425.        a  CUG  call indication in the initial address message received) or
  2426.        the called party belongs to a CUG. The  call  set-up  is  continued
  2427.        only in cases where the information received checks with the infor-
  2428.        mation stored at the destination exchange. Table 2/Q.730  indicates
  2429.        the action to be taken by the destination exchange as the result of
  2430.        the validation check.
  2431.  
  2432.             In cases where a call is rejected as the result of the valida-
  2433.        tion  check because of incompatible CUG information, a release mes-
  2434.        sage including the cause parameter indicating one of the  following
  2435.        values is sent towards the originating exchange:
  2436.  
  2437.                ##55:         Incoming calls barred within CUG
  2438.  
  2439.                ##87:         Called user not member of CUG
  2440.  
  2441.                ##88:         Incompatible destination
  2442.  
  2443.             Figure 2/Q.730 illustrates example message flows for CUG calls
  2444.        with decentralized administration of CUG data.
  2445.  
  2446.  
  2447.  
  2448.        3.3         Call set-up procedure with  centralized  administration
  2449.        of CUG data
  2450.  
  2451.  
  2452.             In the local exchange an indication is  stored,  showing  only
  2453.        whether  the  user has one or none of the closed user group facili-
  2454.        ties.
  2455.  
  2456.  
  2457.  
  2458.  
  2459.  
  2460.  
  2461.  
  2462.  
  2463.  
  2464.  
  2465.  
  2466.        3.3.1         Originating exchange
  2467.  
  2468.  
  2469.             The originating exchange requests the CUG validation check  to
  2470.        the  dedicated  point  by invocation of the "CUG check 1" operation
  2471.        through  TCAP.  This  operation  and  associated   parameters   are
  2472.        described in S 3.4 of this Recommendation. The following actions at
  2473.        the originating exchange depend on the result  of  this  validation
  2474.        check:
  2475.  
  2476.                a)         CUG call indication
  2477.  
  2478.                 If the result of the validation check for the calling user
  2479.        at  the  originating exchange indicates that the check for the cal-
  2480.        ling user has been successful, the interlock code of  the  selected
  2481.        CUG  possibly  together  with  an  outgoing  access  indication  is
  2482.        obtained.  The  initial  address  message  forwarded  to  the  next
  2483.        exchange  then includes the interlock code together with an indica-
  2484.        tion that the call is a CUG call without outgoing access or  a  CUG
  2485.        call with outgoing access.
  2486.  
  2487.                b)         Non-CUG call indication
  2488.  
  2489.                If the result of the validation check  indicates  that  the
  2490.        call  should  be  dealt with as a non-CUG call, the initial address
  2491.        message forwarded to the next exchange then  does  not  include  an
  2492.        interlock code nor a CUG call indication.
  2493.  
  2494.                c)         Call rejected
  2495.  
  2496.                If the result of the validation check  indicates  that  the
  2497.        call is to be rejected, the call set-up is not initiated.
  2498.  
  2499.  
  2500.        3.3.2         Transit exchange
  2501.  
  2502.  
  2503.             Refer to S 3.2.2.
  2504.  
  2505.  
  2506.        3.3.3         Destination exchange
  2507.  
  2508.  
  2509.             In the case of an incoming CUG call for which  the  validation
  2510.        check  for  the  calling  user has successfully been performed, the
  2511.        received initial address message includes the  interlock  code  and
  2512.        CUG  call  indication  possibly  with  an  indication that outgoing
  2513.        access is allowed.  The  destination  exchange  then  forwards  the
  2514.        information  received  in  the initial address message to the dedi-
  2515.        cated point for CUG validation check. In this case, the destination
  2516.        exchange  invokes  the  "CUG  check 2" operation through TCAP. This
  2517.        operation and associated parameters are defined in  S 3.4  of  this
  2518.        Recommendation.
  2519.  
  2520.                a)         Check successful indication
  2521.  
  2522.                If the result of the validation check  indicates  that  the
  2523.  
  2524.  
  2525.  
  2526.  
  2527.  
  2528.  
  2529.  
  2530.  
  2531.  
  2532.        check  has  been  successful, the index of the CUG selected for the
  2533.        called  user  and  possibly  an  outgoing  access  indication   are
  2534.        obtained.  The  CUG  call set-up request is forwarded to the called
  2535.        user with these indications.
  2536.  
  2537.                b)         Non-CUG call indication
  2538.  
  2539.                If the result of the validation check  indicates  that  the
  2540.        call  should be dealt with as a non-CUG call, the set-up request of
  2541.        a non-CUG call is forwarded to the called user.
  2542.  
  2543.                c)         Call rejected
  2544.  
  2545.                If the result of the validation check  indicates  that  the
  2546.        call  is  rejected,  the  reason  why the call has been rejected is
  2547.        obtained. A release message including the cause parameter  indicat-
  2548.        ing one of the values as listed in S 3.2.3 is sent towards the ori-
  2549.        ginating exchange.
  2550.  
  2551.  
  2552.        3.3.4         Dedicated point
  2553.  
  2554.  
  2555.             At the dedicated point, the CUG validation check is  performed
  2556.        according  to  the  rules  defined in Recommendation Q.85. The pro-
  2557.        cedures between the dedicated point and the exchange  follow  those
  2558.        as defined in the ASE part of this Recommendation.
  2559.  
  2560.             Figure 3/Q.730 illustrates an example message flow for  a  CUG
  2561.        call with centralized administration of CUG data.
  2562.  
  2563.                                  H.T. [T1.730]
  2564.                                   TABLE 1/Q.730
  2565.                 Action at the gateway with a network without CUG
  2566.  
  2567.                                    capability
  2568.  
  2569.        _______________________________________________________________________________
  2570.                CUG call indicator in IAM                            {
  2571.              Action at the gateway exchange
  2572.                             }
  2573.        _______________________________________________________________________________
  2574.         CUG without outgoing access                 {
  2575.         Release the call with cause ##88
  2576.          }
  2577.        _______________________________________________________________________________
  2578.         CUG with outgoing access                    {
  2579.         Treat the call as an ordinary call | ua)
  2580.          }
  2581.        _______________________________________________________________________________
  2582.         Non-CUG                                    Treat the call as an ordinary call
  2583.        _______________________________________________________________________________
  2584.  
  2585.       |
  2586.       |
  2587.       |
  2588.       |
  2589.       |
  2590.       |
  2591.       |
  2592.       |
  2593.       |
  2594.       |
  2595.       |
  2596.       |
  2597.       |
  2598.       |
  2599.  
  2600.  
  2601.  
  2602.  
  2603.  
  2604.  
  2605.  
  2606.  
  2607.  
  2608.  
  2609.  
  2610.  
  2611.                                                 |
  2612.                                                 |
  2613.                                                 |
  2614.                                                 |
  2615.                                                 |
  2616.                                                 |
  2617.                                                 |
  2618.                                                 |
  2619.                                                 |
  2620.                                                 |
  2621.                                                 |
  2622.                                                 |
  2623.                                                 |
  2624.                                                 |
  2625.  
  2626.  
  2627.  
  2628.  
  2629.  
  2630.  
  2631.  
  2632.  
  2633.  
  2634.  
  2635.  
  2636.  
  2637.                                                                                      |
  2638.                                                                                      |
  2639.                                                                                      |
  2640.                                                                                      |
  2641.                                                                                      |
  2642.                                                                                      |
  2643.                                                                                      |
  2644.                                                                                      |
  2645.                                                                                      |
  2646.                                                                                      |
  2647.                                                                                      |
  2648.                                                                                      |
  2649.                                                                                      |
  2650.                                                                                      |
  2651.  
  2652.  
  2653.  
  2654.  
  2655.  
  2656.  
  2657.  
  2658.  
  2659.  
  2660.  
  2661.  
  2662.  
  2663.  
  2664.  
  2665.  
  2666.        a) Discard the interlock code parameter and  change  the  CUG  call
  2667.        indicator  of  the  optional  forward  call  indicator  to indicate
  2668.        non-CUG call or discard the whole parameter if appropriate.
  2669.  
  2670.  
  2671.  
  2672.  
  2673.  
  2674.  
  2675.  
  2676.  
  2677.  
  2678.                                            Tableau 1/Q.730 [T1.730], p. 45
  2679.  
  2680.                                  H.T. [T2.730]
  2681.                                   TABLE 2/Q.730
  2682.                Handling of a CUG call at the destination exchange
  2683.  
  2684.        ____________________________________________________________________________________________________________________________________________
  2685.                                                                                              Class of called user
  2686.                                                                                                              |
  2687.  
  2688.            CUG call indicator in IAM       CUG match check
  2689.                                                                 No ICB              ICB                       CUG + IA                No ICB
  2690.        ____________________________________________________________________________________________________________________________________________
  2691.                                            Match             CUG call    |
  2692.                                                                          |
  2693.                                                                          |
  2694.  
  2695.                                                                             Release cause ##55    CUG call                         |
  2696.                                                                                                                                    |
  2697.                                                                                                                                        {
  2698.  
  2699.  
  2700.                                            No match           {
  2701.  
  2702.                                             {
  2703.  
  2704.  
  2705.  
  2706.  
  2707.         CUG with OA not allowed                                                                                 Release cause ##55
  2708.  
  2709.  
  2710.  
  2711.        ____________________________________________________________________________________________________________________________________________
  2712.                                            Match             CUG call    |
  2713.                                                                          |
  2714.                                                                             Release cause ##55    CUG+OA call                      |
  2715.                                                                                                                                    |
  2716.                                                                                                                                       Non-CUG call
  2717.                                            No match           {
  2718.  
  2719.  
  2720.         CUG with OA allowed
  2721.                                            Non-CUG call                                                      |
  2722.                                                                                                              |
  2723.                                                                                                              |
  2724.                                                                                                              |
  2725.                                                                                                              |
  2726.                                                                                                              |
  2727.                                                                                                              |
  2728.                                                                                                              |
  2729.                                                                                                              |
  2730.                                                                                                              |
  2731.                                                                                                              |
  2732.                                                                                                              |
  2733.                                                                                                              |
  2734.                                                                                                              |
  2735.  
  2736.  
  2737.  
  2738.  
  2739.  
  2740.  
  2741.  
  2742.  
  2743.  
  2744.  
  2745.  
  2746.                                                                                                                 Non-CUG call
  2747.  
  2748.        ____________________________________________________________________________________________________________________________________________
  2749.         Non-CUG                            -                  {
  2750.         Release the call with cause ##88
  2751.          }                                 Non-CUG call      Non-CUG call
  2752.        ____________________________________________________________________________________________________________________________________________
  2753.  
  2754.       |
  2755.       |
  2756.       |
  2757.       |
  2758.       |
  2759.       |
  2760.       |
  2761.       |
  2762.       |
  2763.       |
  2764.       |
  2765.       |
  2766.       |
  2767.       |
  2768.       |
  2769.       |
  2770.       |
  2771.       |
  2772.       |
  2773.       |
  2774.       |
  2775.       |
  2776.  
  2777.  
  2778.  
  2779.  
  2780.  
  2781.  
  2782.  
  2783.  
  2784.  
  2785.  
  2786.  
  2787.  
  2788.  
  2789.  
  2790.  
  2791.  
  2792.  
  2793.  
  2794.  
  2795.  
  2796.                                         |
  2797.                                         |
  2798.                                         |
  2799.                                         |
  2800.                                         |
  2801.                                         |
  2802.                                         |
  2803.                                         |
  2804.                                         |
  2805.                                         |
  2806.                                         |
  2807.                                         |
  2808.                                         |
  2809.                                         |
  2810.                                         |
  2811.                                         |
  2812.                                         |
  2813.                                         |
  2814.                                         |
  2815.                                         |
  2816.                                         |
  2817.                                         |
  2818.  
  2819.  
  2820.  
  2821.  
  2822.  
  2823.  
  2824.  
  2825.  
  2826.  
  2827.  
  2828.  
  2829.  
  2830.  
  2831.  
  2832.  
  2833.  
  2834.  
  2835.  
  2836.  
  2837.  
  2838.                                                           |
  2839.                                                           |
  2840.                                                           |
  2841.                                                           |
  2842.                                                           |
  2843.                                                           |
  2844.                                                           |
  2845.                                                           |
  2846.                                                           |
  2847.                                                           |
  2848.                                                           |
  2849.                                                           |
  2850.                                                           |
  2851.                                                           |
  2852.                                                           |
  2853.                                                           |
  2854.                                                           |
  2855.                                                           |
  2856.                                                           |
  2857.                                                           |
  2858.                                                           |
  2859.                                                           |
  2860.  
  2861.  
  2862.  
  2863.  
  2864.  
  2865.  
  2866.  
  2867.  
  2868.  
  2869.  
  2870.  
  2871.  
  2872.  
  2873.  
  2874.  
  2875.  
  2876.  
  2877.  
  2878.  
  2879.  
  2880.                                                                          |
  2881.                                                                          |
  2882.                                                                          |
  2883.                                                                          |
  2884.                                                                          |
  2885.  
  2886.  
  2887.  
  2888.                                                                                                |
  2889.                                                                                                |
  2890.                                                                                                |
  2891.                                                                                                |
  2892.                                                                                                |
  2893.                                                                                                |
  2894.                                                                                                |
  2895.                                                                                                |
  2896.                                                                                                |
  2897.                                                                                                |
  2898.                                                                                                |
  2899.                                                                                                |
  2900.                                                                                                |
  2901.                                                                                                |
  2902.                                                                                                |
  2903.                                                                                                |
  2904.                                                                                                |
  2905.                                                                                                |
  2906.                                                                                                |
  2907.                                                                                                |
  2908.                                                                                                |
  2909.  
  2910.  
  2911.  
  2912.  
  2913.  
  2914.  
  2915.  
  2916.  
  2917.  
  2918.  
  2919.  
  2920.  
  2921.  
  2922.  
  2923.  
  2924.  
  2925.  
  2926.  
  2927.  
  2928.                                                                                                                                                   |
  2929.                                                                                                                                                   |
  2930.                                                                                                                                                   |
  2931.                                                                                                                                                   |
  2932.                                                                                                                                                   |
  2933.                                                                                                                                                   |
  2934.                                                                                                                                                   |
  2935.                                                                                                                                                   |
  2936.                                                                                                                                                   |
  2937.                                                                                                                                                   |
  2938.                                                                                                                                                   |
  2939.                                                                                                                                                   |
  2940.                                                                                                                                                   |
  2941.                                                                                                                                                   |
  2942.                                                                                                                                                   |
  2943.                                                                                                                                                   |
  2944.                                                                                                                                                   |
  2945.                                                                                                                                                   |
  2946.                                                                                                                                                   |
  2947.                                                                                                                                                   |
  2948.                                                                                                                                                   |
  2949.                                                                                                                                                   |
  2950.  
  2951.  
  2952.  
  2953.  
  2954.  
  2955.  
  2956.  
  2957.  
  2958.  
  2959.  
  2960.  
  2961.  
  2962.  
  2963.  
  2964.  
  2965.  
  2966.  
  2967.  
  2968.  
  2969.  
  2970.  
  2971.  
  2972.  
  2973.        IA Incoming access
  2974.  
  2975.        OA Outgoing access
  2976.  
  2977.        ICB Incoming calls barred
  2978.  
  2979.        Match The interlock code in the received IAM  matches  one  of  the
  2980.        CUGs to which the called user belongs.
  2981.  
  2982.        No match The interlock code does not match any of the CUGs to which
  2983.        the called user belongs.
  2984.  
  2985.        Note  - As OA attribute of the called user is of no concern at  the
  2986.        destination exchange, CUG+OA class is equivalent to CUG, and CUG/IA
  2987.        class is equivalent to CUG+IA in this table. Subscription  of  pre-
  2988.        ferential  CUG  by  the  called  user is also of no concern in this
  2989.        table.
  2990.                                            Tableau 2/Q.730 [T2.730], p. 46
  2991.  
  2992.  
  2993.  
  2994.  
  2995.  
  2996.                                                      Figure 2/Q.730, p. 47
  2997.  
  2998.  
  2999.  
  3000.  
  3001.  
  3002.  
  3003.  
  3004.  
  3005.  
  3006.  
  3007.  
  3008.  
  3009.                                                      Figure 3/Q.730, p. 48
  3010.  
  3011.  
  3012.  
  3013.  
  3014.  
  3015.  
  3016.  
  3017.  
  3018.  
  3019.  
  3020.  
  3021.  
  3022.  
  3023.  
  3024.  
  3025.  
  3026.  
  3027.  
  3028.  
  3029.  
  3030.  
  3031.  
  3032.  
  3033.  
  3034.  
  3035.  
  3036.  
  3037.  
  3038.  
  3039.  
  3040.  
  3041.  
  3042.  
  3043.  
  3044.  
  3045.  
  3046.  
  3047.  
  3048.  
  3049.  
  3050.  
  3051.  
  3052.  
  3053.  
  3054.  
  3055.  
  3056.  
  3057.  
  3058.  
  3059.  
  3060.  
  3061.  
  3062.  
  3063.  
  3064.  
  3065.  
  3066.  
  3067.  
  3068.  
  3069.  
  3070.  
  3071.