When eNodeB sends "UE Context Release Request" message to MME ?

Question

There are couple of procedures are defined which consist of NAS as well as RRC signalling messages exchange.
Some of the NAS message sends to an UE through RRC Connection Reconfiguration message as piggybacked and some as DL Info transfer.

I want to know, Is there any procedure exists in lte when an UE receives RRC Connection Reconfiguration along with NAS message and responds back to network with NAS message first and then Reconfiguration Complete to eNodeB.

Usually, I saw UE sends RRC Connection Reconfiguration Complete message first then NAS response message.

Answer 1

if there is NO UL/DL data flow for any UE , UE_INACTIVITY_TIMER will be started ,once its expired eNB will send "UE Context Release Request" message to MME.

Answer 2

Hello,

One scenario where an eNodeB sends a Ue context release request to MME is when UE sends a detach request to eNodeB with cause EPS detach or switch off.

Thanks,
Hashim

Answer 3

There may be so many scenarios in which eNodeB can trigger "UE Context Release". Following are few example -
1. Cell is congested (crunch of radio resources)
2. Cell goes down
3. Not enough user plane processing resources etc and many more.

Please go through 3GPP 36.413.