Impact of 5G SA Deployment with EPS-FB on Control Plane Signaling Load

5G NR
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1

One question guys:

For the people who deployed 5G SA recently with epsFb (no VONR) what is the impact saw on signaling load increase on control plane?

Any figure ?

2

There should not be any signaling load increase on 5G RAN side.

Reason: After UE initiate VoNR call, gNB will receive PDU session resource add / modification request, since gNB cannot entertain VoNR call, it will reply with PDU Session reject or PDU session accept with rejected 5QI-1.

And then gNB will send RRC release to UE.

So compare to VoNR enable Vs EPSFB enable, there is no change in signalling, rather we are reducing RRC reconfiguration to UE for 5QI-1 configuration.

But signaling on n26 interface will increase, as its needed for EPSFB

3

Thanks!

I am actually worried about the fact that (compared to VoNR) everytime we close a VoLTE call registration may be required on AMF (for NR return procedure).

So an increase of signaling load proportional to the increase of epsfb call should be expected compared to VoNR.

Every time UE terminate epsfb call return to NR should be expected to keep UE on NR, so that is the part I am referring to.

4

In case of when UE comes back to NR, call flow is → UE send RRC Reconfiguration complete to gNB, followed by registration.

In my opnion registration messages are not heavy compare to RRC reconf messages.

So it wont increase signaling load.

But if there is further UE capability enquiry by gNB (which may sometime required, not all the time) then it will increase signalling by some amount.