I just found this:

http://www.libelium.com/development/waspmote/documentation/lora-vs-lorawan/

Hi everyone,

I am not sure to understand the difference between LoRa module and LoRaWAN module... I first thought LoRa was for end clients and LoRaWAN for the gateway.
But then I saw in the example code there is LoRa<>LoRa communication.

I am quite lost.
Let's say I want to have a dozen sensors and one gateway. What modules should I buy ?

Thanks is advance,