Sg NB release with action-desirable-for-radio-reason. Is it a failure?

Hi All,
Sg NB release with action-desirable-for-radio-reason. Is it a failure?


Not heard about this cause till now.
Will search 3GPP for this cause.

Is this during NSA to SA switching?

Not during switching. Log is from NSA SgNB release cause, query was: is it a failure cause or normal release?

Just checked the standard for this - doesn’t give much details.
Checked Huawei documentation, it is counted as a Normal Release when eNB release SgNB.

Oh, means it is count as normal release, then query is: when this cause is triggered?

You need standards for that, and I cannot find something useful in my googling. :frowning:

Other experts can comment.

Maybe it’s due to handover.

it can Be as Nokia as Radio network layer , or it might be to as normal release like you are connected to new Target and releasing the old gNB

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Any conclusion regarding this case? Anyone knows possible reasons for this SgNB release with assumption that it is not during 4G serving cell changing?

2 cases:
1- UE sends A2 for PSCell
2- UE sends A3 for PSCell but PSCell change was refused by anchor due to missing relation with target for example

Actually it is case3: faulty 5G RRU and ue fail in rach attempt to sync with NR

If ue fails in NR Rach, UE sends SCG failure information to eNB and eNB sends “sgnb release request” to gNB but the screenshots above shows gNB is sending “sgnb release required” message which is not applicable for NR rach fail case

Sorry @O.B, I wasn’t clear enough. I had similar issue yesterday so I gave the reason I had, but I agree for that above :slight_smile:

I was testing the same. The one scenario comes when the UE in coverage of ENDC(NSA) and now let suppose UE are now out of the coverage from the 5G or in simple terms when there is no coverage of 5G. In that case “SgnBreleaseRequired” comes and cause : action-desirable-for-radio-reasons.