ForewordIntroduction1 Scope2 References3 Definitions and abbreviations4 Functional Split between BSC and BTS5 Information Model6 Elementary Procedures7 Structured Procedures8 Message Details9 Coding 7 Structured Procedures 3GPP52.021Network Management (NM) procedures and messages on the A-bis interfaceRelease 17TS Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM Applicable structured A-bis procedures are described in GSM 12.22.