VNCviewer 4bit 2bit for very slow connection.

[Venturini Francesco]

You are right sometimes I had more then 2000ms, but I think that there are 
two problems.
One is the latency time and one is the transfert rate.What I have seen 
is that bad line with high latency time have low bandwidth with very
low transfert rate.
I tell this because with the evaluation version pcanywhere I have 
the same problem with 8 bit depth, but with 2 bit depth (white,black,light
gray,dark gray) work very well.





>
>I think I see what you mean.  It also defines the problem a little more
>clearly, thank you.  I had in my mind's eye one of those palmtops with
>little serial links or GSM cellphone connections...
>
>Anyway, I think the issue here might not actually be bandwidth (which is
>what encoding and bit-depth helps) but latency.  Run a 'ping' utility
>between the two machines and you'll probably see what I mean - a ping time
>above 500ms will make for a very slow VNC experience no matter how much
>actual bandwidth is available.  VNC traffic, apart from sustained streams
>caused by a large update, tends to be sent in small chunks which wouldn't
>take long but for the latency.
>
>Believe me, I have run VNC across T1 and cable lines which were separated
>by a congested router - there was no problem with bandwidth (updates
>arrived very quickly, even for large screen areas) but the latency was
>horrible - the user sitting at the machine was typing into an IRC window
>and I was seeing the text on my local IRC screen before I saw the letters
>marching across his inputline.
>
>In my tests with the 14.4k modem, the server (with the modem) was on a
>reasonable ISP with good connectivity and the client was connected to the
>JANet - very low latency, in the 100ms range - and apart from large
>updates, which were affected by bandwidth, the speed of the connection was
>unhampered due to the low latency.
>
>Unfortunately, there is very very little we can do about latency.  The
>client has to send mouse updates to the server, which then has to send
>screen data back.  This is a round trip which on a reasonable net is
>acceptable but on a slow net becomes intolerable - as you are noticing.
>The only solution is to wait for Italy to upgrade it's networking...
>
>Of course, if you find for some reason that ping times are good but
>bandwidth is poor... then it is time to revisit the encoding question :).
>
>--------------------------------------------------------------
>from:     Jonathan "Chromatix" Morton
>mail:     chromi "at" cyberspace.org  (not for attachments)
>uni-mail: j.d.morton "at" lancaster.ac.uk
>
>The key to knowledge is not to rely on people to teach you it.
>--------------------------------------------------------------
>Contributing to the VNC Project - http://www.uk.research.att.com/vnc/
>Macintosh VNCserver v3.3.2 beta2.2 now posted at:
>	http://chromatix.autistics.org/vnc/
>
>
>
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