Remote Desktop Protocol in Windows CE
Summary: Remote Desktop Protocol (RDP) 5.0 for Microsoft Windows CE 3.0 is a presentation protocol that allows a "thin client" to communicate with a terminal server through a network connection, either through dial-up networking or a high-speed Ethernet. (3 printed pages)
What Is RDP?
RDP is a presentation protocol that allows a Microsoft® Windows® CE "thin client" to communicate with a terminal server across a local area network (LAN) or wide area network (WAN) or by means of a dial-up, integrated services digital network (ISDN), digital subscriber line (DSL), or virtual private network (VPN) connection. RDP is designed to provide remote display and input capabilities over network connections for Windows-based applications running on a server.
The native presentation protocol is RDP 4.0 for Windows NT® Server 4.0, Terminal Server Edition and RDP 5.0 for Windows 2000 Terminal Services. However, the two versions are fully compatible, so Windows CE clients can connect to either of these servers.
Key Features of RDP
RDP is based on the T.120 family of protocol standards defined by the International Telecommunications Union. As a multichannel-capable protocol, RDP allows for separate virtual channels to carry presentation data, serial device communications, and highly encrypted data, such as keyboard and mouse activity. In addition, the architectural features support multipoint data delivery, which transmits data from an application in real time to multiple parties without sending the same data to each session individually.
The activity involved in sending and receiving data through the RDP stack is essentially the same as the seven-layer OSI model standards for common LAN networking today. Data from an application or service to be transmitted is passed down through the protocol stacks, sectioned, directed to a channel, encrypted, wrapped, framed, packaged onto the network protocol, and finally addressed and sent over the wire to the client. The returned data works the same way only in reverse, with the packet being stripped of its address, unwrapped, decrypted, and so on until the data is presented to the application for use. Key portions of the protocol stack modifications occur between the fourth and seventh layers, where the data is encrypted, wrapped, framed, directed to a channel, and prioritized.
RDP adds value to your client platform by making it easier for applications developers to create software solutions. Because the RDP protocol stack is fully implemented on the Windows 2000 Terminal server and the Windows CE client, developers can create terminal server applications without the programming overhead associated with encrypting, packacking, and transmitting data over the wire.
For more information on how applications interact on a terminal server and what to be aware of when developing applications for the Windows terminal server infrastructure, look at the "Optimizing Applications for Windows NT Server 4.0, Terminal Server Edition" white paper.
The following table provides an overview of the available features.
|Unicode compatible||16-bit character set|
|Network connection||Client connection over LANs and WANs and through dial-up networking, ISDN, DSL, and VPNs|
|Local printing||Printing to a local printer attached to a PC client|
|User-centric session||Client remembers previous logon name for each connection
Connection to an active or disconnected session using difference screen resolution than the original session
|Bitmap caching||Optional caching of display bitmaps in memory for improved performance
Optional compression for low-bandwidth connections
|Encryption||Three levels of encryption to help secure communication|
See the Microsoft Windows 2000 Terminal Services Web page at http://www.microsoft.com/windows2000/guide/server/features/terminalsvcs.asp for more information on RDP and Microsoft Terminal Services. See the International Telecommunications Union Web site at http://www.itu.int for more information on the T.120 family of protocols.