Continous Artnet streaming...

[enttec]

i have never seen udp packet loss as an issue

richard

Packet loss can happen anywhere, it's impossible to make sure it never happens.
A switch will drop packets, the nodes can drop it if 2 packets arrive too close to each other or it get's busy ....
The tcp/ip stacks that all of us use can drop UDP without warning for a number of reasons.

What I'm saying is because there is no ack, there is no way of knowing that the off frame was ever received. UDP was designed for cases where you don't care about losing packets, in these applications we do.
So there are 2 options either switch to TCP which was designed specifically for making sure every packet got to destination (unlikely) or stream Unicast UDP packets continuously. That way if a packet does get lost it will only be until the next update which would hopefully very shortly after.

Thanks

Nicolas
ww.enttec.com

[samsc]

im my experience doing this for 4 years now - udp/ethernet packet loss has never been an issue.
its been dodgy software in various artnet boxes that broke things.
Artnet box designers never expected the continuous volume of traffic.

TCPIP is has not been necessary.
TCPIP has poor response to failure in realtime systems.
I would say if boxes cant handle udp in realtime - handling tcpip is even harder - and much more complex.

Its much better to work in open loop.
UDP Failure recovery times are immediate - and require no re-negotiation.

Handling TCPIP re-negotiation is often not handled correctly either. ( i remember pulling the network cable out of a hog3 years ago, and it never came back online... )

[samsc]

I count dmx input network packet loss- i read all output artnet packets ( and artnet status ) from the network input.

I check the sequence id in the artnet packet - and count the errors.

I have never seen a significant number of packets lost over the nextwork.

[enttec]

Artnet box designers never expected the continuous volume of traffic.

Yes, I know and we fell in that trap too.
First versions of the datagate firmware would die if you send more than 12 universes, it never came to us people would be broadcasting 40 universes of artnet.
New versions can handle this a LOT better but it's still prone to missing packets when you get to the upper limit.
With Unicast it's not an issue and never was.
Unfortunately, situations where box manufactures and software designers can talk aren't very common.
So this is good Richard if we know what the other is expecting it allows us to make the whole system work better.
that's my 2 cents any way

Cheers

Nicolas

www.enttec.com

[samsc]

So this is good Richard if we know what the other is expecting it allows us to make the whole system work better.
that's my 2 cents any way


www.enttec.com

thanks nicolas.

i appreciate your input.

this stuff gets hammered - and the slightest flaws show up....

most of the shows i do with this stuff are both huge and high profile.
i did a 30 universe show very early on at the wynn hotel in las vegas - and it really really needed to work perfectly the entire time - and it does as far as i know.
i worked with unicast artnet from the very beginning. artnet always supported this.
they use fibre switches, and that kindof thing.

richard

[samsc]

thanks nicolas.

i appreciate your input.

this stuff gets hammered - and the slightest flaws show up....

most of the shows i do with this stuff are both huge and high profile.
i did a 30 universe show very early on at the wynn hotel in las vegas - and it really really needed to work perfectly the entire time - and it does as far as i know.
i worked with unicast artnet from the very beginning. artnet always supported this.
they use fibre switches, and that kindof thing.

richard

Simon at stage electrics just did a 48 universe show with luminex boxes, and unicast artnet, and reports no problems at all.

[enttec]

We had a client in the US that did a 200 universe !!!! display with datagates, and it worked fine too, there was no visible lag between any of the outputs.

Unicast isn't a problem and scales very well. I guess we just need to get the word out there !

Nicolas
www.enttec.com

[samsc]

We had a client in the US that did a 200 universe !!!! display with datagates, and it worked fine too, there was no visible lag between any of the outputs.

Unicast isn't a problem and scales very well. I guess we just need to get the word out there !

Nicolas
www.enttec.com

thanks nicolas.