aaf plugin xrun:1711 error

[elabbing]

Hello,
I set 2 host to use aaf plugin for TSN test. I followed TSN-doc guidelines and aaf.txt doc.
Simply, after hosts is ready and syncing though ptp4l, phc3sys, qdisc,
then I try to run a basic test, no switch between, back to back linked hosts,
obtaining the following error.

#Talker
sudo speaker-test -p 12500 -F S16_BE -c 2 -r 48000 -D aaf0

#Listener
sudo arecord -F 25000 -t raw -f S16_BE -c 2 -r 48000 -D aaf0 | \
>         aplay -F 25000 -t raw -f S16_BE -c 2 -r 48000 -D default
Playing raw data 'stdin' : Signed 16 bit Big Endian, Rate 48000 Hz, Stereo
Recording raw data 'stdin' : Signed 16 bit Big Endian, Rate 48000 Hz, Stereo
underrun!!! (at least 24,460 ms long)
arecord: xrun:1711: read/write error, state = RUNNING

This error happens after a random period, tipically less than 60sec.
I followed TSN doc settings, but I noticed that value in aaf plugin configuration and cbs qdisc are suggested differrently between aaf.txt doc and TSN doc.

Any prompt to get out of this?
Many thanks

[elabbing]

More, in aaf.txt doc is reported:

...
frames_per_pdu 6
...
Note that the plugin requires
the period size is multiple of the 'frames_per_pdu' configuration.

For example, to stream the pink noise generated by 'speaker-test', run:

$ speaker-test -F S16_BE -c 2 -r 48000 -D aaf0 -p 12500

Period = 12500
frames_per_pdu = 6
12500/6 = 2083.3333...

Now the result is not a integer.

Any hints, please?