Protocols and bandwidth?

[KenHorse]

Let's say I'm connected to a remote Proxmox server that has a VM running Windows. And that VM is sending me it's desktop (let's say running a typical Windows app).

What protocol is being used to send that VM's console to my browser and what kind of bandwidth is involved? (obviously the bandwidth depends on the content being sent but my question is more is it HTML, streaming video or something else?

 

[sterzy]

It depends. If you are talking about the console in the Proxmox VE Web GUI that uses VNC [1] over a web socket by default. The transmitted information is then rendered using noVNC [2]. There are also alternatives such as SPICE [3]. What is actually transmitted depends on the protocol used.

AFAIK VNC can use different compression methods and encodings, but the simplest explanation is probably that it first transmits a full image of the remote desktop pixel by pixel. After this initial phase it then continues to only transmit rectangles that change. Again, this is simplified, but that is the basic idea here. In any case, it's not HTML. I guess you could see this as a kind of “video stream”, but that is a very loose term (e.g., video streams can also be encoded and compressed in a myriad of ways).

[1]: https://en.wikipedia.org/wiki/Virtual_Network_Computing
[2]: https://novnc.com/noVNC/
[3]: https://www.spice-space.org/spice-protocol.html