џWPCL ћџ2BJ|xа АH аа АА X агга ХА6p&А6p&Х аеЮ† а Hр аааУ Уб cмˆ4 PŽТ б Fascicle VI.7 Р-Р Rec. Q.707 Ф ФPAGE1У Уб cмˆ4 PŽТ б ЮееЃ† а HH аааб cмˆ4 PŽТ бPAGE1У Уб cмˆ4 PŽТ б Fascicle VI.7 Р-Р Rec. Q.707 Ѓеа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаа X  аб cмˆ4 PŽТ бAll drawings appearing in this Fascicle have been done in Autocad. ‚У УRecommendation Q.707 Ср8GСб cмˆ4 PŽТ бTESTING AND MAINTENANCE б cмˆ4 PŽТ б1ТX ТGeneralФ ФЦЦ С СIn order to realize the performance requirements described in Recommendation Q.706, means and procedures for signalling network testing and maintenance are required in addition to the means defined in Recommendations Q.703 and Q.704. ‚У У2ТX ТTestingФ ФЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС2.1С   Сб cмˆ4 PŽТ бУУSignalling data link testЦЦ а H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СAs defined in Recommendation Q.702, РSР 1, the signalling data link is a bidirectional transmission path for signalling. Testing and maintenance functions can be initiated independently at either end. С СThe signalling data link and the constituent parts of the digital and analogue versions are described in Recommendation Q.702, РSР 1. а H аС СThey must be tested before being put into service to ensure that they meet the requirements of Recommendation Q.702, РSР 3. С СSince interruptions of the signalling data link will affect many transactions, they must be treated with the utmost care. Appropriate special measures should be taken to prevent unauthorized maintenance access which could result in interruptions to service. These special measures may include marking or flagging the equipment and indications on distribution frames or test bays where access is possible (see Recommendation M.1050 [1]). а H аС СThe signal unit error rate monitor and the alignment error rate monitor described in Recommendation Q.703, РSР 10, also provide means for detecting deterioration of a signalling data link. а H аС СFurther studies are required with reference to Recommendation V.51 [2]. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС2.2С   Сб cмˆ4 PŽТ бУУSignalling link testЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СAs defined in Recommendation Q.703, РSР 1.1.1 and illustrated in Figure 1/Q.701, the signalling link comprises a signalling data link with signalling link functions at either end. а H аС СIn the following, an onР-Рline signalling link test procedure is specified which involves communication between the two ends of the concerned signalling link. This procedure is to be used when a signalling link is activated or restored (see Recommendation Q.704, РSР 12). The signalling link becomes available only if the test is successful. This procedure is intended for use while the signalling link is in service. In addition, local failure detection procedures should be performed at either end; these are not specified in this Recommendation. а H аС СIn case the signalling link test (SLT) is applied while the signalling link is in service the signalling link test message is sent at regular intervals T2 (see РSР 5.5). The testing of a signalling link is performed independently from each end. а H аС СThe ability to send a signalling test acknowledgement message, defined below, must always be provided at a signalling point. а H аС СThe signalling point initiating the tests transmits a signalling link test message on the signalling link to be tested. This message includes a test pattern which is chosen at the discretion of the end initiating the test. After receiving a signalling link test message, a signalling point responds with a signalling link test acknowledgement message on the signalling link identified by the SLS contained in the signalling link test message. The test pattern included in the signalling link test acknowledgement message is identical to the test pattern received. С СThe signalling link test will be considered successful only if the received signalling link test acknowledgement message fulfills the following criteria: а H аТа ТТ№ ТС€ Сa)СpСthe SLC identifies the physical signalling link on which the SLTA was received.ЦЦ а H аТа ТТ№ ТС€ Сb)СpСthe OPC identifies the signalling point at the other end of the link.ЦЦ Та ТТ№ ТС€ Сc)СpСthe test pattern is correct.ЦЦ а H аС СIn the case when the criteria given above are not met or a signalling link test acknowledgement message is not received on the link being tested within T1 (see РSР 5.5) after the signalling link test message has been sent, the test is considered to have failed and is repeated once. In the case when also the repeated test fails, the following actions have to be taken: а H аТа ТР-РТ№ ТSLT applied on activation/restoration, the link is put out of service, restoration is attempted and a management system must be informed.ЦЦ Та ТР-РТ№ ТSLT applied periodically, for further study.ЦЦ а H аС СThe formats and codes of signalling link test and signalling link test acknowledgement messages used for signalling link testing are specified in РSР 5.4. ‚У У3ТX ТFault locationФ ФЦЦ С СFault location operations, employing particular manual or automatic internal test equipment are left to the discretion of the individual signalling points. С СTests requiring provision of messages are for further study. See [3]. ‚У У4ТX ТSignalling network monitoringФ ФЦЦ а H аС СIn order to obtain information on the status of the signalling network, monitoring of the signalling activity must be provided (for example measures of the signalling load on the signalling data link). The specification of such means and procedures is contained in Recommendations Q.791 and Q.795. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС‚У У5С  Сб cмˆ4 PŽТ бFormats and codes of signalling network testing and maintenance messagesЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФ Ф5.1Тh  ТУУGeneralЦЦ а H аФФС СThe signalling network testing and maintenance messages are carried on the signalling channel in message signal units, the format of which is described in Recommendation Q.703, РSР 2. As indicated in Recommendation Q.704, РSР 14.2.1, these messages are distinguished by the configuration 0001 of the service indicator (SI). The Sub Service Field (SSF) of signalling network testing and maintenance messages is used in accordance with Recommendation Q.704, РSР 14.2.2. а H аС СThe Signalling Information Field (SIF) consists of an integral number of octets and contains the label, the heading code and one or more signals and indications. 5.2Тh  ТУУLabelЦЦ а H аФФС СFor signalling network testing and maintenance messages, the label has the same structure as the label of signalling network management messages (see Recommendation Q.704, РSР 15.2). 5.3Тh  ТУУHeading code H0ЦЦ а H аФФС СThe heading code H0 is the 4Р-Рbit field following the label and identifies the message group. The different heading codes are allocated as follows: С С0000 Spare С С0001 Test messages С СThe remaining codes are spare. аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH јP Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаТX  ТТX јТС€  СС€ HС5.4С   Сб cмˆ4 PŽТ бУУSignalling link test messagesЦЦ аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бФФС СThe format of the signalling link test messages is shown in Figure 1/Q.707. ‚Ср KСб cмˆ4 PŽТ бFigure 1/Q.707 Љ CCITT 35550 б cмˆ4 PŽТ б а H аС СThe signalling link test messages, are made up of the following fields: Та ТР-РТ№ ТLabel: (32 bits), see РSР 5.2ЦЦ Та ТР-РТ№ ТHeading code H0: (4 bits)ЦЦ Та ТР-РТ№ ТHeading code H1: (4 bits)ЦЦ Та ТР-РТ№ ТSpare bits: (4 bits)ЦЦ Та ТР-РТ№ ТLength indicator: (4 bits)ЦЦ Та ТР-РТ№ ТTest pattern: (УУnФФ РxР 8 bits, 1 УУ nФФ 15).ЦЦ а H аС СIn the label, the signalling link code identifies the signalling link on which the test message is sent. С СThe heading code H1 contains signal codes as follows: вЦ‡H8( €јш` и P @ Цв‡ааbi ts D C B A ˆвЦ‡H8( €јш` и P @ Цв‡ 0 0 0 1 signalling link test message (SLTM) ˆвЦ‡H8( €јш` и P @ Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHјшP И џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа0 0 1 0 аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHЈ hџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџH˜ hаH јPЈџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаsignalling link test acknowledgement message (SLTA) ˆа H ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаС СThe length indicator gives the number of octets which the test pattern comprises. С СThe test pattern is an integral number of octets and is chosen at the discretion of the originating point. 5.5Тh  ТУУTimeР-Рout values and tolerancesЦЦ ФФ б cмˆ4 PŽТ бвЦ‚Hxh˜Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј xџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа‚Ср TСб cмˆ4 PŽТ бQ.707 Timer Ср WСRange а hи ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџpи P Ј xhџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаб cмˆ4 PŽТ бˆа hи аб cмˆ4 PŽТ бвЦ‚Hxh˜Цв‡Ср#€YСб cмˆ4 PŽТ бT1 (see РSР 2.2) Ср#€]С4Р-Р12 s а hи аб cмˆ4 PŽТ бˆа hи аб cмˆ4 PŽТ бвЦ‚Hxh˜Цв‡а h аб cмˆ4 PŽТ бSupervision timer for signalling link test acknowledgement message аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџhР(€pШ ˜џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа(equal or greater than T6 of Q.703) а hи аб cмˆ4 PŽТ бˆа hи аб cмˆ4 PŽТ бвЦ‚Hxh˜Цв‡аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџpи P Ј xhџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬаСр#€YСб cмˆ4 PŽТ бT2 (see РSР 2.2) Ср#€]С30Р-Р90 s а hи аб cмˆ4 PŽТ бˆа hи аб cмˆ4 PŽТ бвЦ‚Hxh˜Цв‡б cмˆ4 PŽТ бInterval timer for sending signalling link test messages аЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџhР(€pШ ˜џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа а hи аб cмˆ4 PŽТ бˆа HH ааЬџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџHpи P Ј XА`ИhР!(#џџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџџЬа ‚У У6ТX ТState transition diagramsФ ФЦЦ а H аС СThe state transition diagram is intended to show precisely the behaviour of the signalling system under normal and abnormal conditions as viewed from a remote location. It must be emphasized that the functional partitioning shown in the following diagram is used only to facilitate understanding of the system behaviour and is not intended to specify the functional partitioning to be adopted in a practical implementation of the signalling system. ‚Ср BСб cмˆ4 PŽТ бFIGURE 2/Q.707 (feuillet 1 sur 2) Љ T1109700Љ88 б cмˆ4 PŽТ б Ср BСб cмˆ4 PŽТ бFigure 2/Q.707 (feuillet 1 sur 2) Љ T1109710Љ88 б cмˆ4 PŽТ б У УС СReferencesФ Ф [1]Тh  ТCCITT Recommendation УУLining up an international pointР-РtoР-Рpoint leasedд Д-д circuitФФ, Vol. IV, Rec. M.1050.ЦЦ [2]Тh  ТCCITT Recommendation УУOrganization of the maintenance of international telephoneР-Рtype circuits used for data transmissionФФ, Vol. VIII, Rec. V.51.ЦЦ [3]Тh  ТУУIbid.ФФ, РSР 5.ЦЦ