User Data Header in SMPP SUBMIT_SM

 

SMPP optional Parameters for concatenation and port addressing

 

SMPP concatenation related optional parameters:

(sar_msg_ref_num,

sar_total_segments, 

sar_segment_seqnum) 

 

SMPP port addressing related optional parameters for WAP application:

(source_port, 

destination_port)

 

 

MT concatenation

In GSM network, the SMS size is limited to 140 bytes. In CDMA it can be shorter or longer depending on the network configuration. In fact, it can be unlimited (well, limited to 64Kb) if the SMSC takes care of the concatenation. This is known as "long-SMS" format. Most GSM SMSC don't support long-SMS due to billing policies (the MNO prefers charging for every SMS fragment separately), while most CDMA SMSC do support long-SMS.

 

User Data Header

In GSM network, those parameters are encoded as User Data Header in the short_message (user data) field. If there is UDH for GSM MT message, it must set the UDHI flag in the esm_class field. So that's why esm_class=0x40 (0 1 0 0 0 0 0 0) for concatenated SMS.

 

Here is a UDH with both port addressing and concatenation segementation:

 

0B05040B8423F10003110B01

 

Here is a UDH with port addressing:

 

0605040B8423F1

 

Here is a UDH with concatenation segementation:

 

050003110B01

In GSM network, SMPP short_message = UDH + UD, if those UDH is used,  max UD lenght in each SMS should be 140 - UDH length.

 

In CDMA network, UDH is not used in short_message (user data), so we have to use standard SMPP optional parameters for concatenation and WAP application push.