The following additional GFP requirements have been identified for the IN studies:Interaction of GSL with the BCP SIB(s).Granularity of SIBs. The lowest granularity level of a SIB contains only that functionality needed to describe the network capability it defines. By combining the functionality of a number of SIBS one may create SIBs of a higher granularity. The ideal granularity for SIBS is determined by:the service requirements;the reusability requirements.The granularity of SIBS is achieved by the recursive use of SIBs. The lowest granularity level SIBs are subject tostandardization in the Q. 12x3 Recommendations. The higher granularity SIBS are not required to be standardized and therefore no stage 2 descriptions are needed for these higher level granularity SIBs.Data modelling: A formal description of SIB data is required, in order to be unambiguous, concise and precise. The use of formal data description provides for a smooth mapping to the lower planes. In order to be in line with these planes the use of ASN.l should be considered.