"UDP" vs "UDP SERVICE" difference

In the “TCP/IP Application Note” file for the BC660K there is two possible ways open an UDP connection:

1 - “UDP” client

What is the difference between these two? On the Application Note there is not much information, the only difference I could notice is that the send/recv commands requires extra parameters for (2).
Rather than that, I do not see any other difference.

Can anyone tell more about the differences?

UDP SERVICE is similar to UDP Server,The module acts as the server side

Thank you for the reply @herbert.pan-Q .

Then, what would be more appropriate to work with MQTT-SN?

You should implement MQTT-SN through the MQTT application protocol
Quectel_BC660K-GL_MQTT_Application_Note_V1.1.pdf (417.4 KB)

Just a follow-up on the topic, the MQTT-SN is working fine with the “UDP SERVICE”, so we decided to go with this approach.