LP-CC1352P7: WI-SUN examples difference between ns_* and ns_*_src

HI, 

Just a quick question about the WI-SUN examples in the new impleLink CC13x2 26x2 SDK 5.40.00.20.

I was testing WI-SUN with the SDK 5.20 with examples ns_br,ns_node and ns_coap_node. With the new SDK 5.40, it has the extra examples as ns_br_src,ns_node_src and ns_coap_node_src. 

I was wondering what is the difference between the ns_* and ns_*_src.  Which ones I should use? the ns_* or the ns_*_src?

Thanks so much for your help!

Regards,

waikong