VNC vs. X11 Forwarding

linuxtechie · #1 (**permalink**) 29 Nov 09, 12:23 PM

Folks,

Ofcourse this is directed towards those who have played with both. Question being: VNC as we know paints everything from the source server to the remote connection( is this right? ) while X11 client just obeys whatever painting request sent to it from the X11 server, so which is fast? I am planning for a headless linux box and hence was weighing on these two fronts.

Google didn't hit back any direct answer and hence am putting forth this to you.

+LT

hemantha · #2 (**permalink**) 29 Nov 09, 11:37 PM

x forwarding. Over a 256 kbps connection, loading a firefox window from a remote machine is so slow, i've never been patient enough to let it complete. 'ssh -X' though is very usable.

linuxtechie · #3 (**permalink**) 30 Nov 09, 01:17 PM

Quote:

Originally Posted by hemantha

x forwarding. Over a 256 kbps connection, loading a firefox window from a remote machine is so slow, i've never been patient enough to let it complete. 'ssh -X' though is very usable.

Thanks for the reply hemantha. I see that this is your first post to TE... Welcome aboard mate! Have a nice one. Start up with introducing yourself in the introduction lounge/forum.

+LT

linuxtechie · #4 (**permalink**) 30 Nov 09, 03:43 PM

Did some research and compiled them on my blog:

Quote:

VNC vs X11 Forwarding

Did some research around and compiled following, they are pretty interesting:

* VNC typically uses fewer round-trips than X, particularly as an application starts up. Your link is quite high bandwidth, but if the latency is high, you may find things appear more quickly if you use VNC than if you use X.
* X, however, generally requires much less bandwidth once the application is up and running. This is because it makes more use of resources at the terminal (fonts, cursors, etc). With VNC these are all rendered at the server and copied over the network. So X will often be faster, but VNC works across more platforms and is less dependent on the facilities at the terminal.
* X applications will die when the connection is broken, whereas a VNC viewer can disconnect and reconnect as many times as it likes and the applications keep running. This is particularly useful if you have long-running apps, or if you wish to connect from more than one place.
* People seem to be forgetting one of the more important factors - normally when you run an X server (such as XWin32 for Windoze) the heavy memory usage is at the user's end. The applications you start on the server and that connect to your X server are relatively light-weight. With VNC you reverse that role again, not only will you most likely run your apps on your server, but also the X server itself will then be on that server. With a few users running (VNC) X servers memory usage could be significant.
* Previously I used XWin32 at work, but everytime the machine (or just XWin32) crashed I would lose all my sessions. Also, XWin32 can be quite heavy for your PC - depends a bit on how much memory you have and all that. Nowadays (ever since I learned of VNC) I and several colleagues run VNC X servers on our admin server and connect there with the VNC clients. With SSH and port forwarding we're also able to pick up our sessions from home (mostly through dial-up ISDN, usable but not fast) as well.
* I also use VNC at home to access the VNC server on my Linux box. Speed is good (would be better even with 100Mbit ethernet instead of 10Mbit) and again it doesn't matter whether my W98 box crashes, the server will stay up.
* I've used VNC a long time ago too when I first tested it over a 2Mbit connection, and I recall that as very usable. X connections over that connection are slow anyway.

Your mileage may vary - what window manager and the like you use matters a lot too. The simpler the graphics the less data, etc. It can't be put as simple as you think.

Source: VNC vs X-terminal

linuxtechie on the net!: VNC vs X11 Forwarding

+LT

linuxtechie · #5 (**permalink**) 1 Dec 09, 03:47 PM

Updates:

Tried both and yeah VNC shined out much better than X forwarding. So VNC is the way I am going...

+LT

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VNC vs. X11 Forwarding Discussion under Open Source and Linux, part of the Software Zone category on TechEnclave; Folks, Ofcourse this is directed towards those who have played with both. Question being: VNC as we know paints everything ...