Know RDS and VDI Desktop Virtualizations

Remote Desktop Services configuration

My query is simple: I want to use the data and applications on a different computer using the network connection. How do I do this??

On a high level, the experts will suggest two ways to achieve this:

1.  Terminal Services(TS) or Remote Desktop Services(RDS)
2.      Virtual Desktop Integration(VDI)




Both of these technologically different solutions help to perform the same operation, but vary heavily on the way these are implemented. Let us understand both of these a little, to understand which one suits the best under what circumstances.

1.       Terminal Services(TS) or Remote Desktop Services(RDS):

This service was first launched by Microsoft, and utilized a very simple architecture with the following parts:

• Client: The computer which needs to do the data and application processing.
  
• Server/ Host: The remote computer who’s Operating System will be used for the processing.
  
• Protocols: The set of rules which will help in client to server communication.
  

In case of TS/ RDS, the protocol used was Remote Display Protocol (RDP).

This system had some great advantages:

• Since majority of the processing could be done on the remote server, the client machine was left to do just a part of the processing. Such machines were called ‘thin clients’. These thin clients were much cheaper than the normal PCs with operating system.
  
• Licensing costs for clients were lesser than the server OS license cost. 
  
• Because of comparatively reduced processing, less heat and power is generated in the thin clients, than the traditional PCs. The lesser power consumption means lesser costs.
  
• Reduce operations also ensure that the thin clients have a longer refresh cycle than the traditional PCs.
  

But, along with these advantages, there were some setbacks too to this system:

• Many applications were incompatible when shared. This was due to the different specifications on client server and client machines.
  
• Due to the multi-user operation on a shared server, the desktop could not be personalized.
  
• User isolation posed problems in keeping the data secured from the other users.
  

The experts tried to find the solution to these problems, and the TS/ RDS system underwent many transformations. An extension to this system which is widely being used today is Virtual Desktop Integration (VDI).

2.       Virtual Desktop Integration(VDI):

Again, the complete system of client and server was divided into 3 parts, but each part had sub-divisions, which made the complete architecture complex for deploying VDI solutions:

         Endpoint Device: The client machine which receives the output. Under VDI solution, there are 4 endpoint devices classified, out of which 2 are common:

• Thin clients- They do major processing on remote server OS, and a minor on client OS.
  
• Zero clients- The complete processing is done on the remote sever OS.
  

         Server: The machine with the operating system, on which processing will be done. This server uses masking technique to divide a single OS into multiple virtual operating systems:

• Each virtual OS has its own desktop, and is called a virtual machine (VM).
  
• Hypervisor, a software application that creates the VMs and maintains them.
  

         Connection Brokers: For communication between client and server. In VDI architecture, these protocols are used by connection brokers, which connect the endpoint devices to each VM desktop session. Initially, RDP was used, which was later replaced by some batter and graphically enhanced protocols.

This architecture is difficult to deploy. But it has some significant advantages over the TS/ RDS environment:

• Each user has his/ her own copy of OS with an individual desktop. This provides a flexibility to customize the individual applications.
  
• The VDI architecture supports multiple OS environments. This solves the incompatibility issues which existed with the TS/ RDS systems.
  
• The multiple users have their sessions isolated.  This protects their data to be accessed by another user.
  
• VDI includes the snapshot technology, which helps the user to rollback to an earlier event. This is useful if the OS is corrupted by the virus or the malware program.
  
• The graphics display and the multimedia is very efficiently handled by the VDI environment, which is difficult to achieve in TS/ RDS systems.

These benefits clearly make the VDI integration outstanding and an obvious choice, except for the following setbacks:

• The deployment of VDI architecture is complex and far too costly compared to the TS systems set-up.
  
• A very high IT skill is required for the VDI solution deployment and maintenance.
• Deploying various components from different vendors may cause incompatibility issues.
  

Read more on VDI in The Basics Of Desktop Virtualization.

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