Resolving IMS and Radio Erlang Mismatch in VoLTE

CORE
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1

Hello Experts,

Hope you’re having a great day.

Is anyone here using VoLTE?

I’m encountering an issue where IMS reports double the Erlangs compared to what the radio reports. Has anyone experienced this before?

How do you normalize this mismatch?

Is there a specific setting in the radio that needs to be enabled?

2

Primarily, check the SCTP, DSCP, and IKEPEER settings, as they play a crucial role in codec negotiation and resolving codec mismatches.

A common issue arises when DSCP (Differentiated Services Code Point) values do not align, or there is a 2-to-1 mismatch, impacting traffic handling.

Additionally, ensure that both IMS and Radio performance metrics are using the same interval definition. The standard traffic formula for normal

Erlang calculation is:

Erlang = Call Seconds / 3600

Verifying these settings can help diagnose and correct discrepancies.

3

Hi,
If you’ve got a back-to-back user agent or a RTP relay in your IMS your reporting may see two calls for every one, for example the call leg through the IMS to the TAS and then a new Call-ID coming from the TAS to the other networks, this would cause you to see 2 calls for every 1 call made, and the counters mismatching.