ÿWPCL ûÿ2BJ|xÐ ` ÐÐÌÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿH øÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÌÐÐ °°°è ÐÑ Âx„|ü@Ž ÑÐ Å°6Ø'°6Ø'Å ÐÓÓÃÃRecommendation I.605ÄÄ Áà-ÁAPPLICATION OF MAINTENANCE PRINCIPLES TOƒ Áà.ÁSTATIC MULTIPLEXED ISDN BASIC ACCESSESƒ 1.ÁHÁÃÃScope of applicationÄÄ Ð À ÐÁHÁThis Recommendation covers the maintenance of the static multiplexed basic rate access, controlled by the network, and describes the operations and maintenance aspects of the V4 interface. ÁHÁThe V4 interface is defined in Recommendation Q.512. The specification of the operations and maintenance aspects of the V4 interface is the subject of this Recommendation. ÁHÁThis Recommendation follows the maintenance principles as defined in Recommendation M.20 and applies to the basic rate access connected to the exchange via a multiplexer. ÁHÁThe principle of controlled maintenance is applied for maintaining the static multiplexed basic rate access. ÁHÁControlled maintenance is a method of sustaining a desired technical performance by the systematic application of supervision, testing and performance sampling in order to minimize preventive maintenance and to reduce corrective maintenance. 2.ÁHÁÃÃNetwork configuration for maintenance activitiesÄÄ ÁHÁFigure 1/I.605 shows the general reference configuration of the multiplexed basic rate access, connected via a digital link to the Exchange Termination (ET). ÁàÐFÁFIGURE 1/I.605ƒ ÁàÐMÁƒ ÁàÐ6ÁÃÃEquipment configuration for maintenance of theÄă ÁàÐ?ÁÃÃmultiplexed basic rate accessÄă ÃÃNote 1ÄÄ © The digital link, as defined in CCITT Recommendation G.701, can make use of a variety of transmission techniques and media complying with Recommendations G.703 and G.704. ÃÃNote 2ÄÄ © The digital link may not be present. (Colocated configuration). 3.ÁHÁÃÃRelationship to the maintenance of the basic rate accessÄÄ Ð X ÐÁHÁThe same principles as given in Recommendation I.603 for the ISDN basic rate accesses directly connected to the local exchange, should be applied. Therefore, the NT1 and LT for the basic rate accesses connected via a static basic access multiplexer to the local exchange must have the same functions as NT1 and LT for the basic rate accesses connected directly to the local exchange. ÁHÁ(Loopback mechanism must be implemented according to Recommendation I.603.) ÁHÁIn order to support these principles, operation and maintenance information has to be exchanged between the digital section for the ISDN basic rate access and the exchange termination (ET). This information is conveyed in the Cv1 Channel, which is defined in Recommendation Q.512. This Cv1 Channel is shown in Figure 2/I.605. ÁàÀIÁFIGURE 2/I.605ƒ ÁàÀPÁƒ ÁàÀ/ÁÃÃInformation exchange between the digital section for the ISDN basicÄă ÁàÀ7ÁÃÃrate access and the local exchange termination (ET)Äă ÁHÁThese functions, which are allocated within this Cv1 Channel are defined in Recommendation G.960 on the digital section for the ISDN basic rate access. ÁHÁThese functions can be classified according to: ÁHÁ©Á  Áactivation/deactivation procedures; ÁHÁ©Á  Áerror and status reporting to the exchange (ET); ÁHÁ©Âà  Âfailure localization within the digital section for the ISDN basic rate access;Ô ñ,ÔÆÆŒ ÁHÁ©Âà  Âconveyance of control information from the exchange (ET) to the digital section of the ISDN basic rate access.ÆÆ 4.ÁHÁÃÃMaintenance of the digital link and basic access multiplexerÄÄ 4.1ÁHÁÃÃFailure detectionÄÄ ÁHÁUnlike the ISDN basic access, the digital, link and basic access multiplexer are always in the active state (as seen by the exchange). Continuous automatic supervision, supervising the correct functioning of layer 1 up to basic access multiplexer, is operating. This supervision is called continuous automatic supervision on layer 1. 4.1.1ÁHÁÃÃFunctions applied to the ETÄÄ ÁHÁThe functions which are allocated to the ET are listed below: ÁHÁ©Á  Ádetection of loss of incoming signal; ÁHÁ©Á  Ádetection of loss of frame alignment; ÁHÁ©Á  Ádetection of AIS; ÁHÁ©Á  Ádetection of RAI; ÁHÁ©Á  Ágeneration of the frame signal; ÁHÁ©Á  ÁCRC code generation; ÁHÁ©Á  ÁRAI generation; Ð À ÐÂHH©Âà  ÂCRC monitoring of the incoming signal (basic access multiplexer to the ET);ÆÆ Ð ` Ð ÁHÁ©Á  Ádetection of CRC error information; Ð  ÐÂHH©Âà  ÂCRC error reporting (ET to the basic access multiplexer) (optional);ÆÆ Ð ` Ð ÁHÁ©Âà  ÂAIS generation.ÆÆ Ð Ð ÐÁHÁThe implementation of these functions should be the same as for the ET in the ISDN primary rate access, as defined in Recommendation I.604 for the exchange termination (ET). 4.1.2ÁHÁÃÃFunctions applied to the static basic access multiplexerÄÄ ÁHÁThe functions which are allocated to the basic access multiplexer are listed below: ÁHÁ©Á  Ádetection of loss of incoming signal; ÁHÁ©Á  Ádetection of loss of frame alignment; ÁHÁ©Á  Ádetection of AIS; ÁHÁ©Á  Ádetection of RAI; ÁHÁ©Á  Ágeneration of the frame signal; ÁHÁ©Âà  ÂCRC code generation monitoring of the incoming signal (network to basic access multiplexer) and detection of CRC error information (if provided from the ET);ÆÆ ÁHÁ©Âà  ÂCRC error reporting (basic access multiplexer to the ET).ÆÆ ÁHÁThe implementation of these functions should be the same as for the NT2 in the primary rate access, as defined in Recommendation I.604. ÁHÁIn addition, the following functions are allocated to the basic access multiplexer: ÁHÁ©Âà  Âsending of AIS on the V4 interface, in case of a defect in the basic access multiplexer between the V1 reference point and the V4 interface of the multiplexer;ÆÆ ÁHÁ©Âà  Âsignalling to all the basic rate access the condition "out of service due to failure", in the case of a defect occurring in the basic access multiplexer, between the V1 reference point and the V4 interface of the multiplexer, and in the digital link.ÆÆ 4.1.3ÁHÁÃÃFunctions allocated to the digital linksÄÄ ÁHÁThe functions, which are allocated to the digital links are: ÁHÁ©Âà  Âdetection of loss of incoming signal on either end and within the digital link;ÆÆ ÁHÁ©Âà  Âgeneration and transmission of AIS within the digital link.ÆÆ 4.2ÁHÁÃÃSystem protectionÄÄ ÁHÁÃà                                                    ÄÄ ÁHÁxxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx xxx Ô ñ,ÔŒ 4.9ÁHÁÃÃOverall performance measurementsÄÄ ÁHÁSee Recommendation I.603 for the performance related to the digital section of the basic rate access, and Recommendation I.604 for the V4 digital section. ÁàHOÁÃà         Äă ÁàHOÁƒ