Data being interrupted in 3G network while a call is initiated

Hello All.

It is normally observing in our 3G network that data is interrupted while a call is initiated.

3G network is ZTE.

Whether it is Handset issue or Network configuration issue?

It’s eaither:

You have to enable multi RAB.
Multi RAB is enabled but the rate is very low for the PS.

Have you configured MultiRAB? Means both CS RAB and PS RAB are working?