ArtNET - Amount of universe packets per frame

[Lada LX]

Hi,
I'm programming my own ArtNet node, and I'm struggling with universe packets and ArtSync packet order.
I have one node with 4 unicast ports 0:0, 0:1, 0:2, 0:3 so four DMX universes. When the Ligthjams sends four universes and ArtSync I receive only 3 dmx packets + sync packet per one frame.

A packets sequence like below:
U1
U0
U2
ArtSync
U2
U1
U0
ArtSync
U1
U3
U0
ArtSync
...

Why only 3 universes are sent between sync packets?
The time frame between the sync packet is about 40ms according to configured 25fps. When I don't get all 4 universes in one frame it makes a jerky picture of my LEDs. I don't have enabled Optimize option in the ArtNet Output setting in Lightjams.

Is it some ArtNET convention or I missed something in Lightjams settings?

[Mathieu]

Hi,

Receiving universes out of order is ok but when the optimize option is off, you should receive all universes before the ArtSync packet.

Are you using a WIFI?

[Lada LX]

Hi,
Thanks for the reply.
I have already solved this problem. I use an ethernet connection, but my ethernet module had a small buffer for UDP packets.
It caused, that the 4th DMX packet didn't fit to the buffer, but the sync packet did.
It was confusing to me ;)

Dne neděle 14. února 2021 v 0:41:40 UTC+1 uživatel Mathieu napsal:

[Mathieu]

Hi,

Perfect then!

If you want to support the other artnet specs, packets may not contain all 512 channels and universes with no value changes are not sent (can only be sent once every few seconds). 

[Acid Energy]

Would the use of jumbo frames have any effect in an artnet application? Given that all NICs and switches support this option (sometimes tricky due to different sizing), would that have any reasonable effect?