Deliver report timeout ......

Deliver report timeout ...... SearchSearch
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Nelson Lam
New member
Username: Nelsonlam

Post Number: 39
Registered: 02-2013
Posted on Thursday, August 18, 2016 - 04:30 am:   

Hi Des

Our NowSMS server is connected to a mobile operator's SMSC via SMPP
configured under NowSMS >> SMSC list.
We have SMPP clients who binded to this NowSMS server will submit SMS
to the mobile operator.

Then DLR returned by Operator via Deliver_sm to our NowSMS is successfully relay
back to our SMPP clients.

We observed that sometime the DLR deliver by operator to NowSMS server are not
getting "deliver_sm-resp-ok" acknowledgement. As a result the operator SMSC
is having a lot of DLR deliver_sm timeout retry to re-send the DLR.

We would like to know why NowSMS server not properly response to the deliver_sm ?
Is there any setting issue that we could have missed and causing this problem.

Pls help to resolve this problem.
Thanks.

Best Regards
Nelson
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 8152
Registered: 10-2002
Posted on Thursday, August 18, 2016 - 07:01 pm:   

Hi Nelson,

Des is on holiday.

Assuming either separate sender/reciever connections, or async mode enabled for a transceiver connection, deliver_sm_resp is close to instantaneous.

If a transceiver connection is being used, an async window size that is too large might cause problems for the other side to not see it in a timely fashion.

We'd probably need to see a Wireshark trace and SMSDEBUG.LOG/SMPPDEBUG.LOG to troubleshoot.

But my best guess would be an accounting callback issue, where the callback was raking too long and causing the delay.

-bn

Bryce Norwood
Now SMS/MMS Support
Nelson Lam
New member
Username: Nelsonlam

Post Number: 40
Registered: 02-2013
Posted on Friday, August 19, 2016 - 11:23 am:   

Hi Bryce

- We are using transceiver mode on both side.
- On Operator side (smsc setting) windows size set to 50.
- In the SMSGW.ini >> [SMSGW] section, we have put SMPPServerAsyncWindowSize=40.
- For accounting callback, each transaction processing is well below 10 msec.
- I will try to do the capture and debug log later.

Thanks for your advice.

Best Regards
Nelson
Nelson Lam
New member
Username: Nelsonlam

Post Number: 41
Registered: 02-2013
Posted on Monday, August 22, 2016 - 07:06 am:   

Hi Des / Bryce

- We tried to reduce the WindowSize to 20 but seems not very helpful.
The timeout issue still persist.
- The LOG file and Wireshark capture files were sent to nowsms@nowsms.com
Pls help to checkout if there is any parameter to adjust to resolve this.
Appreciate and thanks.

Best Regards
Nelson
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 8153
Registered: 10-2002
Posted on Tuesday, August 23, 2016 - 03:00 am:   

Hi Nelson,

It does look like an accounting callback issue.

Without studying in excessive detail, I noticed early in the log, situations where the accounting callback was taking 4 or more seconds to complete.

One such transaction for an inbound message can be found by searching for:

01:14:25:854 [19]

The deliver_sm_resp was delayed for 4 seconds waiting for that accounting callback.

01:14:25:870 [19] RetrieveURL: shows the HTTP request for the callback being sent.

01:14:29:245 [19] HttpResponseWait: Ok - shows the HTTP response from the callback being received. (3-1/2 seconds later).

During that same time window, there were other callbacks being processed for outbound...some taking 4 seconds, some faster.

SMSIN accounting callbacks are synchronous and if they do not process quickly they will impede the speed at which messages are accepted on an SMPP connection.

The performance of the callback script needs to be improved.

There is a remote chance that NowSMS is having issues with the accounting web server. You could try adding AccountingKeepAlive=No to the [SMSGW] section of SMSGW.INI. I see no indication of a problem in this area, but it is worth a try.

-bn