SMPP: Message_ID not unique

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Prasad Shetty
New member
Username: Pshetty

Post Number: 4
Registered: 03-2006
Posted on Friday, March 31, 2006 - 02:43 pm:   

Hi Bryce,

I have an application sending SMS messages over SMPP connection. I found that the message_id sent back in the SMPP Submit_SM PDU response by nowSMS is not unique across SMPP sessions, i.e. when the application re-establishes the SMPP connection the message_id series are repeated by the nowSMS gateway.

Could you please let me know how we can resolve this issue or am I missing something here.

Find attached the SMPPDebug.log file for your reference where you will find that the message_id SAR-+919845842073-1-2-1 being repeated.

Thanks & Regards,
Prasad
application/octet-streamSMPPDebug.log
SMPPDEBUG.LOG (95.8 k)
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5757
Registered: 10-2002
Posted on Friday, March 31, 2006 - 05:05 pm:   

Hi Prasad,

Segmented messages might be a problem.

Can you tell me more about how you are submitting these messages into NowSMS, I need to work through the logic flow.

-bn
Prasad Shetty
New member
Username: Pshetty

Post Number: 5
Registered: 03-2006
Posted on Sunday, April 02, 2006 - 05:47 am:   

Hi Bryce,

Yes, the messages are concatenated short messages.

The messages are being submitted by the application using the SubmitSM SMPP Pdu. The info for concatenated messages is contained in the UDH as specified in 3.40 specs, find below the sample UDH for two concatenated messages (the UDH contains two elements):
MSG1-UDH: 0B 05 04 0B 84 00 00 00 03 01 02 01
MSG2-UDH: 0B 05 04 0B 84 00 00 00 03 01 02 02

Where the concatenated element (2nd element) has:
00 -> indicates concatenated message element
03 -> number of octets in the element
01 -> Reference number which remains constant for every short message which makes up a particular concatenated short message
02 -> the total number of short messages within the concatenated short message which is 2
01 -> counter indicating the reference number for a particular concatenated short message (01 in MSG1-UDH & 02 in MSG2-UDH)

The application starts the reference counter from 1 every time it establishes the SMPP connection.

Let me know if you need any further information.

Thanks & Regards,
Prasad
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 5771
Registered: 10-2002
Posted on Monday, April 03, 2006 - 06:29 pm:   

Hi Prasad,

Unfortunately, for segmented messages, we are building this id based upon the segmentation information (including the reference counter). We do this so that we can ensure that if multiple SMSC connections are defined to NowSMS, all segments of a multipart message get routed out via the same SMSC connection (otherwise the message may not be reassembled correctly by the recipient).

While we should be able to readjust this logic, there is nothing that we can do to make a quick change. It's a change that will likely take several weeks.

In the meantime, if there is anyway that you can maintain your reference counter so that it does not start over each SMPP connection, that would be a good idea.

-bn
Prasad Shetty
New member
Username: Pshetty

Post Number: 6
Registered: 03-2006
Posted on Tuesday, April 04, 2006 - 08:25 am:   

Hi Bryce,

While we can make this change in the application, this will still not solve the problem as the reference counter is maintained in 1 octet (as per 3.40 spec), so will have to re-start from 1 once the reference counter reaches 255. So in cases where we are sending lot of messages to the same device (which we are doing in our case), we will still encounter this problem.

Would appreciate if you could expedite providing a fix for this issue.

Thanks for your support.

Best Regards,
Prasad