Virtual Network Computing
Introduction
• About VNC
• Why VNC ?
• VNC Protocol
• VNC Servers & Clients
• Limitations of VNC
• Where to get VNC ?
About VNC
VNC is remote control software
which allows you to view and
interact with one computer (the
"server") using a simple program
(the "viewer") on another
computer anywhere on the
Internet.
About VNC
•
Remote control system of other computer windowing
environments.
• Allows access to “desktops” of like or different operating
systems.
• The two computers don't even have to be the same type, so
for example you can use VNC to view an office Linux
machine on your Windows PC at home.
• VNC is freely and publicly available and is in widespread
active use by millions throughout industry, academia and
privately.
Why VNC ?
• Freedom to choose your favorite computing
environment
– And still have access to the more powerful UNIX system
• Remote access is made possible to the major platforms
– You want to work at home, but you forgot that one critical
file at school on the…
• Reinforces the concepts of client/server software
– Concept foreign to most PC/MAC users
VNC Protocol
• RFB(remote frame buffer) is a protocol for remote access to
graphical user interfaces.
• The protocol simply allows a server to update the frame buffer
displayed on a viewer. Because it works at the frame buffer level it
is potentially applicable to all operating systems.
• This includes X/Unix, Windows, and Macintosh, but might also
include PDAs, and indeed any device with some form of
communications link. The protocol will operate over any reliable
transport such as TCP/IP.
VNC Protocol
• The VNC protocol is a simple
protocol for remote access to
graphical user interfaces. It is
based on the concept of a
remote frame buffer or RFB.
VNC Clients
 Writing an VNC viewer is a simple task, as it should
be for any thin-client system. It requires only a
reliable transport (usually TCP/IP), and a way of
displaying pixels (either directly writing to the frame
buffer, or going through a windowing system).
 VNC clients exist for all things of Unix, Windows,
Macintosh, Java and for smaller hand-held
appliances.
VNC Server
• Provides the “remote” half of the “remote control” system
• Communicates interactions from the remote machine to the local
machine
• Exports the view of the remote “desktop” screen environment to a
local machine
• Imports keyboard and mouse inputs from local machine to remote
machine
VNC Viewer
• Provides the “local” half of the “remote control” system
• Communicates interactions between local machine to the remote
machine
• Imports the view of the remote “deskstop” screen environment to
the local machine
• Exports keyboard and mouse inputs from local machine to remote
machine
Limitations of VNC
• VNC is network resource intensive
•
•
High Bandwidth connection = Good situation
Low Bandwidth connection = Bad situation
• File systems are still separate between different operating
systems
•
Transferring files still requires other mechanisms (e.g. ftp)
• Access to non-Unix platforms do not have good multi-user
support
•
PC/MAC lack general concept of several user access.
Where to get VNC?
• AT&T Laboratories, Cambridge UK
http://www.uk.research.att.com/vnc/
• Available for UNIX environment
Requires system administrator privileges
• Already installed on the CIS machines
•
• Available for Windows platform
•
Requires you to download and install on your machine
• Available for Mac platform
• Available for Java-enabled browsers
Security
• Password
• SSH Encryption
• Virtual Machine
• Isolation
Thank You