by Bryon D Beilman
Getting work Done
There are many compute models that organizations use to get their work done. Centralized, Distributed,
Batch Mode or a combination of the above. For organizations that need to do compute intense applications there are a number of tools that are very powerful. I am tempted to start talking about Gridware, Virtual Machines and server compute models, but the real topic today is the tools that are useful for utilizing resources and getting work done. The focus of this is also based on users who need to run remote applications that may require low latency or be more demanding than the typical office user. Those that can function with Email, a web browser and access to some documents can get away with some of the basic offerings from Microsoft.
Since I cannot cover all the combinations, let's discuss the client configuration where the user has a Windows based laptop and they need to access remote servers.
RDP
The first combination is accessing windows servers and/or remote desktops. Microsoft has a built in protocol called RDP (Remote Desktop Protocol). Each Windows XP desktop has the ability to allow remote connectivity for one person. A Windows 2003 server and up can support multiple simultaneous users based on the number of licenses purchased. If you have a windows 2000 client, you can download the RDP Client tool from Microsoft. The RDP protocol is very efficient, encrypted and works well over the WAN.
VNC
VNC is a client/server set of software that allows remote control of a desktop (Keyboard, Monitor and Mouse) and utilizes the RFB (Remote Frame Buffer) protocol . It works with multiple operating systems and works reasonably well across a WAN. For windows to windows connection, RDP is a better way to go. There are some software products that do not work from RDP (to make sure licensing is honored). VNC does help with this situation because it controls a PC's primary display and will allow someone to remotely connect and control a PC. The power of VNC is really in accessing UNIX servers and workstations. UNIX VNC servers can be started within the X startup configuration, inetd or users can start up their own personal VNC server sessions. There are a number of good Free Packages from RealVNC, TightVNC or others. There are also commercially supported packages that also integrate authentication schemes and offer greater support. It is also nice that you can exit a session (ie from work) and then reconnect to it from home in the same state that you left it.
The challenge or problem with VNC is that it is not encrypted (by default) and that it should be used via a local LAN, VPN or tunneled through SSH. It works well for most light to medium graphics demanding applications. Those doing Large CAD projects may experience delays over WAN connections that may not be acceptable, but it works very well for 90% of the applications out there. If you require OpenGL for your remote applications, the VNC may not be the product for you as it doesn't support it.
NX by NoMachine
NX takes a different approach to remote access. It is built on X (which normally would not be efficient), as anyone who has tried to remotely display XWindows over a WAN has tried, but this product is built on a special NX compression technique, where it compresses the traffic by a number of techniques, reduces network round trips nearly to zero, and adapts real time to network conditions. NX servers also support Windows Servers and understands RDP and RFB protocols. It is a very good solution for remote access to applications.
One of the caveats is that the packages provided (ie RPMs) don't install on older OS's. You can however download the tar file and build and install it yourself.
Exceed and Exceed on Demand by Hummingbird
Exceed and EOD are good remote access tools. Exceed is simply an X server for windows which works well on the LAN, but has the same latency issues over a WAN. Exceed on Demand, or EOD, is designed for WANs and provides a lightweight client that connects to a centralized server that manages, compresses and allows remote access to any Server that is running XDCMP on the network. This is a commercial product but works well for access to UNIX servers.
Citrix
Citrix has a number of products that provide very efficient remote access and their product lines change enough that I cannot comment on them in detail. Citrix has a very effective method of providing remote access over web based protocols and does support windows to Unix and Unix to windows connection models . Products like GotoMeeting, that utilize Citrix servers is very powerful and a super remote support tool, but may not be appropriate for connecting daily and working with remote applications.
Some of these products can work in concert with each other. If you have Hummingbird Exceed (or a free XServer product such as Cygwin) on a windows terminal server and use RDP to remotely display the XWindow traffic.
This is one building block of a compute model that allows the use of centralized servers, remote teleworkers or collaboration between remote offices or design centers. It is not all inclusive but these are tools that I have found very useful an enabling for a number of businesses. Those that want to integrate these technologies who understands how to optimize them for your business should contact iuvo Technologies.