I'm new in SMPP, I read that in concatenated SMS user data header field which contains sequence number used to concatinate different parts of SMS. My question is: Can this field be duplicated for different SMSs? Or it should be unique? I faced problem in parts concatenation when this field duplicated. But it length is really small (4 octet) so it will be duplicated in case of large number of SMSs being sent! Can you please give me more information about this field?
The CSMS reference number only has to be unique among SMS messages sent to the same handset. The purpose is for the handset to be able to separate different incoming concatenated messages from each other when assembling their parts.