If I get the connection details from a service provider who needs the ESME to talk to SMSC in SMPP, do I need to have my own SSMP server running on my machine too? Or can I just build a client to connect to SMSC And send SMS? I am using JSMPP to send sms.
To send SMS through a provider, all you need an ESME which will connect to the SMSC of the provider. This is independent of SMPP library you are using.
If you want to test your ESME and the SMS(s) the ESME is sending, you would be better of with your own SMSC.