While I have read lots of opinions not to use simple GSM Phones to send bulk SMS, I have implemented a couple of these systems and have found them to be working quite well, as long as you follow some simple rules:
- Use lots of phones - we typically have 2-8 per server depending on the volume of SMS. Yes the phones will crash some times, we have seen a simple SE (Don't know the model right now, I think it was a K310i) running for years, and we have seen others crash more than once a month. By using more than one phone and a combined queue, a dead phone will reduce your SMS bandwidth, but will not stall the gateway.
- Ofcourse you can do some least-cost routing in the dequeueing process (Think doifferent carriers for the different phones), but be sure to not introduce a SPOF
- If possible make sure all phones have a known-good unbranded firmware - some provider-branded firmware versions will do strange things with SMS
- Before designing the system, think about deployment: It won't be easy to deploy GSM hardware in a data center. This can be a show-stopper.
Caveat: All the projects have been in Europe. Things might be different elsewhere, especial in the legal department. European carrier TOS tend to be friendlier to subscribers.
