Bursty traffic - Under runs

Hello,

I have a flowgraph as below

Packet Framer custom message block–>PDU to tagged stream -->Modulation
–>Interpolation -->HackRF(osmocom)

What I see is that when there is no packets to transmit HackRF reports
underuns. This is going to be the case with any busty traffic. So how
this should be handled?

Regards
PP