(Background) The use and general aspects of the A bis interface are given in specification TS 48.051. The split of telecommunications functions and management procedures between BSC and BTS are defined in specification TS 48.052. Specification TS 48.056 defines Layer 2 of the signalling messages. The general aspects of NM are defined in specification GSM 12.00. Qx interface and protocol stack are defined in specification GSM 12.01. GSM 12.06 provides the functional requirements supported by the present document. The NM procedures and messages to support these operations over the A bis interface are specified here. Specification GSM 12.20 provides the information model as seen on the OMC-BSC interface. Interworking between this model and the NM messages and procedures provided here is specified in GSM 12.22.

The present document addresses the network management messages and procedures across the A-bis interface, which is defined as Qx in GSM. The information model included here defines the objects and how they are addressed for purposes of operations and maintenance activities. There is a requirement for the A-bis interface to be open to allow interoperation between BTSs of different manufacturers working to the same BSC. The present document addresses this requirement from O&M point of view, which allows this interworking to take place. It shows the split of NM functions between BSC and BTS. The procedures and coding of the messages are specified in detail. In practice, in addition to the present document it is necessary that the content of manufacturer-dependent information fields be specified to fulfill the functionality. It is essential for operation that a BSC can handle the functions used by all its BTSs. Therefore, all items in the present document are considered mandatory unless otherwise indicated in the present document.