Re: Question regarding CDC NCM and VNC performance issue

[Hiago De Franco <hiagofranco@gmail.com>]

From: Hiago De Franco <hiago.franco@toradex.com>

Hi Oliver,

> At first thought my gut feeling is that the packet bonding is killing
> your performance. What does a simple ping do?

Thanks for the reply.

Pinging the device works with or without the VNC connected.

$ ping 192.168.11.2
PING 192.168.11.2 (192.168.11.2) 56(84) bytes of data.
64 bytes from 192.168.11.2: icmp_seq=1 ttl=64 time=0.027 ms
64 bytes from 192.168.11.2: icmp_seq=2 ttl=64 time=0.092 ms
64 bytes from 192.168.11.2: icmp_seq=3 ttl=64 time=0.072 ms
...
64 bytes from 192.168.11.2: icmp_seq=37 ttl=64 time=0.065 ms
64 bytes from 192.168.11.2: icmp_seq=38 ttl=64 time=0.070 ms
64 bytes from 192.168.11.2: icmp_seq=39 ttl=64 time=0.090 ms
^C
--- 192.168.11.2 ping statistics ---
39 packets transmitted, 39 received, 0% packet loss, time 38910ms
rtt min/avg/max/mdev = 0.027/0.076/0.105/0.015 ms

During the ping, nothing changes, VNC continues to be extremely slow.

I switched from NCM to ECM for testing purposes. On ECM, everything works
seamlessly without any issues. It appears that the problem may be specific
to the combination of NCM and the Linux host machine, as the setup works
fine on Windows.

I'm curious if there are issues with NCM and small USB packet lengths.
The VNC application tends to send numerous small packets (1514 bytes).

Regards,
Hiago