title: A robust SMPP library for .NET
body: <p>I'm developing an online SMS messenger and looking for a scalable and robust SMPP library for .NET. I saw EasySMPP (but have some doubts with it) and RoamingSMPP. There are also one but I can't recall it's name. For me the most important is it's scalability, stability and fault tolerance. I may have 500k+ users and several hundreds SMS per second. The communication will be 2 way, receive should be able to reply to SMS msg received from my messenger.
  So I'm interested if anyone can recommend the library which suits my needs? It doesn't matter for me if it's free or commercial.</p>
  
  <p>Thanks</p>