I've been assigned a task to investigate why hepic doesn't generate MOS scores ever since we changed the kamailio interface MTU from 9001 -> 1500.

During my investigation, this is what I have found out so far:

- Putting MTU back to 9001 removes this condition where no MOS was generated.

- I did a tcpdump of port 9063 which is the port used to send data to Hepic capture server and saw it reports packets are fragmented:

- Hepic support also caused by using 1500 MTU on the interface.

- I tried using the following core parameters to see if they could remedy this issue but didn't seem to work:

## MTU related core settings

udp4_raw=-1

udp4_raw_mtu=1500

I can't seem to find any parameters in the siptrace module that controls fragmentation of the packets to Hepic.

Any suggestions on how else to troubleshoot this?

Thanks.

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