Re: FreeNX

[Ralf Gesel|ensetter <rgx@gmx.de>]

Hi Ragnar,

thank you for rising that topic. For Ulsrud, I planned to demonstrate nx 
access to my school's system. Anyone interested?

Am Donnerstag, 27. Januar 2005 16:50 schrieb Ragnar Wisløff:
> I've just had my first session with FreeNX in an LTSP environment
> today. First impressions are mixed. The compression is impressive,
> for flash movies more than 100x. But for interactive sessions the

True. 

> latency renders the page almost useless. The colour depth is less,
> some icons are off and text is misplaced sometimes. General

Latency is usually a result of round trips, which can be avoided by the 
use of nxagent (on server side). Misplaced icons might be due to the 
host system - what client did you use on what platform?

> responsitivity is less than with a clean X session. There are bound
> to be tradeoffs, of course.

As all graphics are cached, menues tend to respond retarded at first 
click but pop up in no time at any further usage.
>
> From what I understand, the protocol used is diffed pngs, which
> explain why things look a bit strange.

You can also switch to jpeg - and here select the quality (depending on 
your bandwidth). True X widgets are transmitted lossless as they are 
taken from local libraries - if however you run java applets or even 
with mozilla, high compression results in jpeg typical artefacts. You 
won't notice those if you perform nx on a beamer.
>
> The load on the server when showing graphics intensive apps like
> flash is about the same with and without nx. In other apps it's
> higher.

This issue is really the one I know least of. Does an NX server need 
similar power as an ltsp server? Or even more as compression takes its 
overhead? As soon as you open your NX server to ordinary users, it is 
advisable to run freeNX on a machine different from your LTSP to avoid 
performance outages during classes.
>
> The setup was a Sarge based server with LTSP 4.1, packages for NX

Ah, tell us: you integrated nx in LTSP4 (as documented?) We couldn't 
test this one, because our woody LTSP3 is not that flexible.

> client built in LBE, and a Sarge package for freenx server side as
> shown on the Ubuntu web site. It was a breeze to make work, but a few

Ah, could you point us to the URL? I made a howto to install nx with 
Woody based Skolelinux on skolelinux.org/de...

> rough edges during the login process.
>
> Does it use less bandwidth? Definitely.
> Is it useful? Perhaps. Not definitely.

Is it more secure: yes, everything runs in ssh - so passwords are not 
transmitted any longer internally. 

For me it is mainly interesting to allow teachers remote access from 
home. Schools that have only 10Mbit networks (say in LDCs) can yet run 
LTSP servers with nx. 

Just my 15 öre (is this 2 cent?)
Regards
Ralf