- SMS protocol information units since defined as part of GSM 040 are not so efficient. The many head section areas in PDU have always been fixed that places the constraint regarding the situations which can be suggested. 3G specs are now being seemed up to search and/or target these types of constraints.Senders to parcels must be notified of status of these parcels. Recipients always must certanly be notified when their parcels is as a result of distribution too. Insufficient distribution notifications brings doubt among customers about your service. They've Been likely to seek solutions from other organizations they may be able trust.