RFB protocol

:"RFB (RF and B) can also refer to "Room, Food, and Beverage" see Comps (casino)."

RFB (“remote framebuffer”) is a simple protocol for remote access to graphical user interfaces. Because it works at the framebuffer level it is applicable to all windowing systems and applications, including X11, Windows and Macintosh. RFB is the protocol used in Virtual Network Computing (VNC) and its derivatives.

Although RFB started as a relatively simple protocol it has been enhanced with additional features (such as file transfers) and more sophisticated compression and security techniques as it has developed. To maintain seamless cross-compatibility between the many different VNC client and server implementations, the clients and servers negotiate a connection using the best RFB version, and the most appropriate compression and security options, that they can both support.

History

RFB was originally developed at Olivetti Research Laboratory (ORL) as a remote display technology to be used by a simple thin client with ATM connectivity called a Videotile. In order to keep the device as simple as possible, RFB was developed and used in preference to any of the existing remote display technologies.

RFB found a second and more enduring use when VNC was developed. VNC was released as open source software and the RFB specification published on the web. Since then RFB has been a free protocol which anybody can use.

When ORL was closed in 2002 some of the key people behind VNC and RFB formed RealVNC, Ltd.in order to continue development of VNC and to maintain the RFB protocol. The current RFB protocol is published on the RealVNC website.

Protocol versions

Published versions of the RFB protocol are as follows:

Developers are free to add additional encoding and security types but they must book unique identification numbers for these with the maintainers of the protocol so that the numbers do not clash. Clashing type numbers would cause confusion when handshaking a connection and break cross-compatibility between implementations. The list of encoding and security types is maintained by RealVNC Ltd and is separate from the protocol specification so that new types can be added without requiring the specification to be reissued.

Limitations

In terms of transferring clipboard data, "there is currently no way to transfer text outside the Latin-1 character set".

ee also

* Virtual Network Computing
* Comparison of remote desktop software

External links

* [http://www.realvnc.com/docs/rfbproto.pdf The RFB Protocol - Version 3.8 (2007-06-18)]
* [http://web.archive.org/web/20040325204925/http://www.realvnc.com/docs/rfbproto.pdf The RFB Protocol - Version 3.7 (2003-08-12)]
* [http://grox.net/doc/apps/vnc/rfbproto.pdf The RFB Protocol - Version 3.3 (1998-01)]
* [http://www.realvnc.com/vnc/how.html How It works]