100% of the time you are working with ANY virtual machine you will be remotely connected, you maybe at the physical server, logged into the local console, looking at the VMware Server Console, but it is still “REMOTE”. The images are being processed, compressed and sent to the software. The virtual machines doesn’t know that, and doesn’t care. The console software can connect from anywhere, on the same machine, across the room or even across the world.
What technologies are being used to transmit these images?
Currently the big 2 are VNC and RDP.
VNC
In computing, Virtual Network Computing (VNC) is a graphical desktop sharing system which uses the RFB protocol to remotely control another computer. It transmits the keyboard and mouse events from one computer to another, relaying the graphical screen updates back in the other direction, over a network.
VNC is platform-independent — a VNC viewer on any operating system usually connects to a VNC server on any other operating system. There are clients and servers for almost all GUI operating systems and for Java. Multiple clients may connect to a VNC server at the same time. Popular uses for this technology include remote technical support and accessing files on one’s work computer from one’s home computer, or vice versa.
(source)
VNC Comments
VNC is a nice tool. It’s improved a bit over the years, but still has several flaws.
1) A VNC server is required for an OS. Many operating systems have them, but some don’t.
2) If a server is available for an OS, it has to be configured through the OS. There is no way to keep the configuration external.
3) RFB doesn’t work well over high latency connections.
4) All RFB clients and servers that I know of are only moderately adaptive to bandwidth.
NX/FreeNX are much better than VNC as far as latency and bandwidth go. Unfortunately, client and server implementations are less available than with VNC.
(source)
Remote Desktop Protocol (RDP) is a multi-channel protocol that allows a user to connect to a computer running Microsoft Terminal Services. Clients exist for most versions of Windows (including handheld versions), and other operating systems such as Linux, FreeBSD, Solaris, Mac OS X, and PalmOS. The server listens by default on TCP port 3389.[1] Microsoft refers to the official RDP client software as either Remote Desktop Connection (RDC) or Terminal Services Client (TSC).(source)
Problems with RDP, or really problems with Microsoft:
Recently during a SP roleout Microsoft changed a flag for remote connections to XP and Vista systems, now if you where using an independant technology, like VNC, Microsoft wouldn’t have been able to ruin your afternoon.
If you install SP3 for Windows XP or SP1 for Vista, the switch for connecting to a console via a RDP session apparently changes from /console to /admin. This means that if you use the /console switch it, it will be ignored and you will only have a regular RDP session.(source)
Keep Reading to See the “Future” of Remote Desktop Software
Faster Options?
They are out there…
ICA
Independent Computing Architecture (ICA) is a proprietary protocol for an application server system, designed by Citrix Systems. The protocol lays down a specification for passing data between server and clients, but is not bound to any one platform.
Practical products conforming to ICA are Citrix’s WinFrame and Citrix Presentation Server (formerly called Metaframe) products. These permit ordinary Windows applications to be run on a suitable Windows server, and for any supported client to gain access to those applications. Besides Windows, ICA is also supported on a number of Unix server platforms and can be used to deliver access to applications running on these platforms. The client platforms need not run Windows; for example, there are clients for Mac, Unix, Linux, and various Smartphones. ICA client software is also built into various thin client platforms.(source)
The proposed Net2Display ™ VESA standard is intended for remoting displays and USB I/O devices with responsiveness, performance and motion video user experience comparable to a local PC. This proposed standard will enable client displays to connect over wired or wireless networks to host computers located centrally in businesses or homes or remotely at service facilities. (source)
[…] discussions about remote display protocols. This article on x86virtualization.com provides a decent overview of VNC, RDP, ICA, and Net2Display. Seems like I recall seeing something somewhere about VMware assisting in the development of […]
June 26th, 2008 at 9:18 pm
[…] discussions about remote display protocols. This article on x86virtualization.com provides a decent overview of VNC, RDP, ICA, and Net2Display. Seems like I recall seeing something somewhere about VMware assisting in the development of […]