TightVNC

Greg Breland gregory "at" netdoor.com
Wed, 15 Aug 2001 22:51:17 +0000


I think there is a lot of confussion about TightVNC.  I will try to
explain to all.  However, http://www.tightvnc.com explains how tightvnc
works better than I can.

Tight is an encoding for VNC.  TightVNC is a "distribution" of VNC with
the tight encoding included.  TightVNC is VNC with some extra option
added such as tight encoding, jpeg compression, zlib compression, and
local cursor.

Because of this, TightVNC can perform at exactly the same speed over a
LAN as VNC because worst case, you could just used Hextile encoding. 

I know this sounds like I nit-picking, but it is an important.  If you
install TightVNC server and Client then you can still use it just like
you use VNC, using hextile encoding, for example.

Now, Tight Encoding VS Hextile Encoding over a LAN, I would bet that
Hextile is faster.  Tight requires more processing time per update that
is sent.  This extra processing makes the data being sent smaller, but
on a 100mbit network this size difference does not make a big. 

This is just a hypothetical, these numbers do not represent reality, and
is only an example.  Say a hypothetical hextile update is 300k; the
encoding takes 20ms and the network takes 200ms to send this 300K to the
client.  Say the Tight update is 150K, takes 60ms to encode and takes
180ms to send.  Hextile is still 40ms faster per update.  Now as the
network speed decreases, the size of the data becomes more critcal.

However, I would also bet that a TightVNC server/client running hextile
with the local cursor option turned on would be faster than standard VNC
which uses Hextile, but does not have the local cursor option.  This is
because the local cursor option tells the server to only send the cursor
information when the cursor shape changes, not evey time the cursor
moves.  This results im much less data and more importantly less network
activity.

Greg



On 15 Aug 2001 20:51:13 +0200, Anouk Kuiling wrote:
> > It is true, I have asked the same question before. But the reply I got was
> that if you are using a LAN connection, then tightvnc is not going to help a
> lot, in fact it will be slower. But if you are on a modem, then tightvnc is
> better.  Normal vnc with HEXTILE coding is better for LAN, this is what I
> have found out.
> 
> Why is TightVNC slow by using a LAN connection and faster by modem
> connection ?
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