Hi Experts,
In case of 5G SA, when will UE trigger registration request with cause “mobilty registration update”?
What are the different possible scenarios to trigger this?
TAU update will cause this.
Next I can think of LTE to NR redirection of handover.
Need to check effect if with/without N26 support.
What about if TAU list is not present in registration accept message?
Then will UE still trigger this?
I think it should! I haven’t explicitly tried this scenario yet.
I think I found in the specs all possible reasons why it should once.
Point 3… Even to update UE caps it will do MRU:
Point 1 confirms what you said:
Attached CR has all possible reasons mentioned.
Please look for ‘24501_CR0683_(Rel-15)_C1-188410’
Let me check, thanks.
Actually we have one issue:
We did SA registration and then release the RRC connection.
As soon as we release the RRC connection, UE is triggering the registration request with cause “mobility update”.
Any thought on this?
Do you have any logs that you could send?
Mostly I am thinking the one you mentioned, the TAU list in Registration accept is not correct.
It is empty.
When the UE in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE receives a request from the upper layers to establish an emergency PDU session or perform emergency services fallback; I see this for Emergncy.
When the UE needs to indicate PDU session status to the network after local release of PDU session(s) as specified in subclauses.
These two seem possible if TAI list is not the culprit.
in my case，UE trigger registration request with cause “mobilty registration update”，its try create NRDC，log will show registration request with “mobility reggistration updating” and registration accept & complete ，than follow log is PDUSessionresourcesetupresponse and PDUSessionresourcemodifyconfirm ，will see transportlayeraddress changed.
1、When UE moves to a new tracking area (TA, Tracking Area) outside the registration area；
2、UE needs to update the negotiation capability or protocol parameters during the registration proces；
3、When UE wants to obtain LADN (Local Area Data Network) information。