Roon RAAT and "An audio file is loading slowly"

[David A]

@David A: Excellent explanation. Thank you!

On my configuration via router, Roon READY was not working fine (mainly on HRs and MQAs). Roon AIR (bit-perfect asynchronous mode) had no problem at all.

Today I had setup Direct Ethernet (Gigabit) connection between my Roon Core (Windows 10 PC) and Devialet Expert, using a second network card. Then I spent many hours using/testing both Roon READY and Roon AIR...

At the end, I came to two conclusions:

1. Switching to Direct Ethernet (Gigabit) connection made an obvious improvement to Roon READY. Still not perfect, but it is almost acceptable.
   
2. A possible cause for Roon READY issues may be the fact that this protocol is much "heavy" for the network (and devices) than Roon AIR. Since now I have a dedicated network card for Roon Core - Devialet communication, it is easy to compare. Thus (see attached pictures):
   

• Average network traffic from Roon Core to Devialet is almost double for Roon READY versus Roon AIR.
  
• Network traffic from Roon Core to Devialet is very fluctuating for Roon READY, while for Roon AIR it is pretty steady.
  
• There is ~8 times more network traffic from Devialet to Roon Core for Roon READY versus Roon AIR.
  

On the other hand, I didn't notice sound quality differences between Roon READY and Roon AIR.
So, I am wondering: why using Roon RAAT, and not Roon AIR?
I am also wondering why Roon Core playing the same track is sending to Devialet almost a double amount of information  for Roon READY versus Roon AIR?

The 6.2Mb/sec is 0.62% of utilization of 1000Mb network. Why to worry about it?

I'm not worry about the bandwidth (quantity), but about the reason for 100% more traffic (quality).

Daniel,

I think some answers are now becoming apparent:

- the higher Roon to Devialet traffic is in large part probably due to the higher bandwidth requirements of TCP which RAAT uses and AIR doesn't.

- the much higher Devialet to Roon traffic is harder to pin down. It's clear the Devialet can be sending more information back to Roon with RAAT (tone control and SAM settings when they are in use, perhaps other info) and if TCP has higher bandwidth requirements then those higher requirements will be operating in both directions so that's part of it also but that doesn't explain why Devialet to Roon with RAAT is roughly 8 times higher than Devialet to Room with AIR when traffic in the other direction is only 2 times higher with RAAT than with AIR.

One thing which intrigues me is the difference in the flow of the traffic shown in your graphs, the fairly even flow with AIR vs the more episodic flow with RAAT. @Confused points our that Devialet say "Asynchronous BitPerfect mode provides optimal audiophile-grade conditions: music is transferred from your computer or smartphone to the amplifier with zero alteration to audio samples. This mode of transfer occurs at the exact same rate as Expert Pro digital-analog conversion rather than the speed imposed by your computer. The amplifier therefore dictates computer behavior rather than the opposite, with AIR intelligence split evenly between the two devices."  The interesting part in that is the last bit which says "with AIR intelligence split evenly between the 2 devices. I'm wondering whether that means that with AIR the computer side uses it's knowledge of the resolution of the file to "push" the data to the Devialet at a regular rate whereas RAAT may require the Devialet to "pull" the data from Roon with regular "send me more" messages. If the Devialet has to initiate more communication with Roon regarding data transmission with RAAT than it does with AIR, that's going to be another cause of higher Devialet to Roon traffic and not only the number of messages being sent but the amount of data in those messages and the higher bandwidth requirements of TCP are going to play a part as well.

The bottom line in all of that is that it seems we have to expect higher traffic flows in both directions with RAAT because TCP has higher bandwidth requirements and there may also be extra traffic from the Devialet to Roon because the Devialet needs to send more data to Roon when using RAAT. Even with that higher amount of traffic in both directions, however, the demand placed on the connection are well within the bandwidth capabilities of both 100 baseT and gigabit ethernet connections so the bandwidth alone shouldn't be a concern for quality purposes.