The main reason is probably database/disk access to insert the DLR values and look them up again.
Also there's an extra deliver_sm from the smsc involved which takes time to process on both sides. If you use a standard install of MySQL for the dlr tables, tuning that will give a big difference. == Rene Van: users [mailto:users-boun...@kannel.org] Namens Nanda Kumar P Verzonden: zondag 24 april 2016 7:11 Aan: users@kannel.org Onderwerp: Create SMS box for handling dlrs Hi, I'm using one instance of bearer box and sms box each and I use kannel to send sms to the SMSC with delivery report parameters (dlr-mask & dlr-url) included in the send-sms url. I have no trouble functionality wise in sending the sms or getting the delivery. However, I do have a problem in the final throughput I see with and without delivery report. If I do not request for delivery report, the speeds are consistent at the rate of 300/sec which the throughput I have configured. However, when I use delivery reports, it starts with the expected throughput but gradually goes down to 25/sec or less. Any idea why this could be? I use kannel 1.4.4 Thanks & Regards, Nanda