JSMPP is a java implementation (SMPP API) of SMPP protocol (currently support SMPP v3.4). It provides interfaces to communicate with Message Center or ESME (External Short Message Entity) and able to handle traffic 3000-5000 messages per second.
SMPP is stand for Short Message Peer to Peer. It is a standard protocol for exchanging SMS messages between SMS entities over TCP/IP or X.25 connections.
This API created to reduce the verbosity of the existing SMPP API. It's very simple and easy to use because it hides the complexity of the low level protocol communication such as automatically enquire link request-response.