With Kannel, you can increase the throughput using the configuration throughput
on the smsc
group in /etc/kannel/kannel.conf (on a default install). more info in the docs
You also have the option of increasing the window size (ie. the number of SMS pending submit_sm_resp) using the max-pending-submits
configuration. The default for that is 10.
There are lots of options for SMPP libraries.. depending on your language of choice:
- Python - https://github.com/dmaclay/python-smpp
- PHP - https://github.com/onlinecity/php-smpp
- Java - https://code.google.com/p/jsmpp/
All of which can work on debian. However the problem is that most of what you will find are software libraries and you would have to build a client on top of them... so maybe not what you're looking for.
The options for high-quality but low-cost SMPP clients are severely limited in my experience!