03-Aug-2019, 09:22
@daniel.avasilichioaei - your test comparing the USB 2 and USB 3 "Gigabit" network interfaces is an interesting one. If I understand correctly, the negotiated link speed is 1 Gbps in both cases but because USB 2 can't support that data rate the effective bandwidth is limited to less than 1 Gbps. Furthermore that limit on the bandwidth seems to avoid hitting the error condition.
Together with what I saw in the WireShark traces you posted earlier that suggests to me that there's some limitation in the Devialet when Roon starts the TCP connection. It seems that although the Devialet is advertising a large window size in fact it can't cope with the initial inrush of data if Roon sends it at 1 Gbps, whereas it is OK if the incoming data rate is less than that. This suggests to me that packets are being dropped in the Devialet's Ethernet device driver or possibly the network stack because for some reason it can't keep up with the initial rush of incoming traffic.
This could be a CPU power limitation although I think that's unlikely as the i.MX6 used on the CI board normally has enough horsepower to handle a 1 Gbps network interface. My best guess based on these symptoms would be that the Ethernet driver or network stack is not correctly configured (number/size of buffers, descriptors, etc.). If that is the case then hopefully a firmware change should be able to fix the problem.
Together with what I saw in the WireShark traces you posted earlier that suggests to me that there's some limitation in the Devialet when Roon starts the TCP connection. It seems that although the Devialet is advertising a large window size in fact it can't cope with the initial inrush of data if Roon sends it at 1 Gbps, whereas it is OK if the incoming data rate is less than that. This suggests to me that packets are being dropped in the Devialet's Ethernet device driver or possibly the network stack because for some reason it can't keep up with the initial rush of incoming traffic.
This could be a CPU power limitation although I think that's unlikely as the i.MX6 used on the CI board normally has enough horsepower to handle a 1 Gbps network interface. My best guess based on these symptoms would be that the Ethernet driver or network stack is not correctly configured (number/size of buffers, descriptors, etc.). If that is the case then hopefully a firmware change should be able to fix the problem.
Roon (Mac Mini), Wilson Benesch Full Circle, Expert 1000 Pro CI, Kaiser Chiara
Warwickshire, UK
