java - Can anybody tell me how to use User Data in smpp? -

can tell me how use user data(udh) in smpp? want send sms specified port.

i use opensmpp project lib..

follow these steps send udh on smpp:

• set udhi bit 1 on esm_class field. simplest way - esm_class = esm_class | 0x40.
• put udh @ beginning of short_message field. read on quick summary. see references know in details how encode udh.

here how encode udh:

• the first byte of udh must mention length (in bytes) of remaining part of udh. since may not know ahead, may have calculate later on.
• then follows 1 or more ie (information element). each ie has 3 parts:
  • first byte: iei (ie indicator). identifies element want encode. there established iei.
  • second byte: ieidl (iei data length). identifies number of bytes holds data part. each established iei has fixed value field.
  • third byte , rest part: ieid (iei data): holds data part. each established iei has fixed format of data.
• count total bytes consumed each ie , put result in first byte.

for sending sms part, can use iei 0x04 or 0x05. have seen 0x05 being used.

references

• 3gpp specification: 23.040
• user data header