Hello CptnCrnch,
 
Thank your for your reply !
If it is send by default, what kind of value is that , because this value should be used on the NPS server.
 
I read every possible Radius related doc, even I open a case on meraki support, still no success !
 
FYI... this is an answer I get from meraki support Engineer 
 
  "there are all the supported attributes in the Access-Request messages sent from the Cisco Meraki access point to the customer's RADIUS server. Unfortunately, the NAS-ID is not one of them" .
 
This is very important fearure, which every other vendor has.
 
Thanks!