Question about vncviewer frame buffer update requests

Sood, Sanjeev sanjeev.sood "at" intel.com
Thu Mar 31 20:05:01 2005


I am new to RFB protocol and trying to understand the protocol. I have
questions regarding the frame buffer update requests in your
implementation.



1.	My understanding is that RFB Frame Buffer Requests are purely
driven by the clients. Is that the case with the RealVnc viewer & server
implementation?
2.	When does the viewer request the update and how often does it do
it? Does it poll at some rate, is it tunable, or is it adaptive to the
network bandwidth?
3.	If Xvncserver does not send any updates without clients asking
for it, could client possibly loose some screen full of data if its
request does not arrive in time before the screen changes? E.g. if
client types in ls -lR command to recursively traverse the root
directory, there can be lot of scrolling and client may miss data until
his next request arrives.
4.	What if there are two viewers connected to same session, would
screen buffer change caused by one viewer be sent to both viewers or
only when the other viewer asks for it?
5.	How would the realVNC viewer react if a RFB server sends it
multiple updates responses for one request (e.g. to deal with the
scrolling case above or when 2nd client to a session causes some change
in the buffer)? Is it a stateless client or does it track request &
responses?



I will really appreciate any help and guidance. Thank you very much,

-Sanjeev Sood