Eclipse Paho focuses on open messaging for machine to machine and Internet of Things. Its objectives include effective levels of decoupling between devices and applications, designed to keep markets open and encourage the rapid growth of scalable Web and Enterprise middleware and applications
Now Paho is kicked off with MQTT client implementation. MQTT is a machine-to-machine (M2M)/"Internet of Things" connectivity protocol. Here's Andy Piper's blog that provides a quick start guide to using the MQTT C client provided in Eclipse Paho.
Well you need a MQTT Server/broker to connect this MQTT client. WebSphere MQ Telemetry is now integrated feature of main WebSphere MQ. You can create a WebSphere MQ queue manager and enable Telemetry support on it to run as a MQTT server. Here is the link to the trail version of WebSphere MQ 7.1.