QCI5 and QCI6 for signaling in VoLTE

Hi friends, please I have a question.
ZTE Network.

I am finding qci 5 and qci 6 for signaling in VoLTE. Is it ok?

QCI5 is IMS - is normal to be there.
QCI6 is Internet Bearer - it is also normal to be there.

In every VoLTE call you will find QCI1, QCI5 and another QCI (6,7,8 or 9) for Internet.

As @RFSpecialist said, generally Qci5 is used for VoLTE signaling.
It’s like that you Qci6 is default bearer.
However I have seen error in some network where SIP signaling creeps onto default bearer.
As long as all your SIP messages have Qci5 marking, you are good.

Is there any problem if qci6 be used instead of qci5?

Yes, it is a problem.
Usually the issue happens due to wrong IP configs.
SIP server IP is outside of TFTs for Qci5 so mobile uses default bearer.
Or someone has incorrectly defined Qci6 in PGW/SGW for IMS signalling.

Ok thanks!
Which is your recommendation?

I check that some cells have qci5 and another have qci6.

Get you CORE team investigate and check config.
QCIs are assigned by PGW/SGW.
If Qci6 is your default bearer then issue is wrong IP range for QCI5.
If Qci6 is not your default bearer then issue is wrong configuration at SGW/PGW for bearer creation.
In either scenario PCRF + SGW/PGW engineer should fix this.

I would also suggest check qci mapping as well in eNodeB.
Like qci 5 mapped to ims signalling.
Qci6 mapped to non gbr.
Which qci used in your network for non gbr traffic generally.
In logs are you seeing 2 pdn connectivity request plus 2 default bearer?

My understanding is that eNB doesn’t assign QCIs and has no role in mapping.
It simply bundles packet on correct bearers.
QCIs are assigned by SGW/PGW based on user profile define in HSS and PCRF.

I agree QCI mapped with IMSI in HSS.
At PGW/SGW end it’s decided from user profile.
But in eNodeB as well, we have mapping of QCI with GBR, non GBR, signalling… so UE come to know traffic type.

If you have in the network QCI 6 configured for VoLTE is ok.
But is not recommend.

Like said above, before and all we know:
QCI 1 and QCI 5 for VoLTE
QCI 6, 7, 8, 9 for Internet