LTE: What does mean by "MS is configured for NAS signalling low priority" ?

Question

What does it mean for MME and UE ? what are action need to do ?

Answer 1

It is used when there is a NAS level congestion. NAS level congestion might be generic or APN based.
Please check this below link for more details:
http://howltestuffworks.blogspot.in/2011/12/nas-level-congestion-control.html

Answer 2

NAS Signalling low priority parameter has been added under NIMTC feature in release 10 for differentiating low priority MTC devices from normal priority UEs. Low priority devices shall get lower priority while performing network operations e.g. attach/TAU/SR as compared to normal priority UEs/devices and network can reject or assign some extra back-off timers in reponse to these requests generated from low priority devices.