With so much Ga Ga over VMware and Xen, the industry overlooks the importance of dozen other players who play key roles in maintaining a thriving virtualization ecosystem.
Let me call the whole ecosystem a “jungle”. Like a jungle which contains all kinds of animals and each one playing a unique distinct role, virtualization ecosystem also has lots of players from thin-client companies to hypervisor companies to connection-brokers. Each of these roles is very critical for the sustenance of the ecosystem.The lion of this jungle is clearly VMware as it has the early mover advantage and also has a large chunk of the hypervisor market. Citrix is yet another lion from a different jungle who is trying to adjust to climatic change(from Server based computing to VDI) and is working desperately hard to establish himself under the new circumstances.
I have represented different components of a VDI solution as layers.The order of arrangement of layers needn’t be the same for all solutions that are deployed across the globe. Different solutions exist for different cases and this is a general approach to VDI. Please make a comment if there is anything that needs to added or modified.
As of today, there is NO SINGLE vendor is known to have a product which by itself is self sufficient to provide the entire VDI solution. There are many players like VMware, Provision, Microsoft and Citrix who have products in many layers of the solution but doesn’t yet cover the entire spectrum. Citrix, Microsoft and VMware have been on a buying spree acquiring startups for the getting more control over the VDI stack. This explains why recently Citrix bought Xen (Hypervisor Company) and VMware acquired Propero, a connection broker company.
Let me describe some of those components.
Thin clients or the End user machines 
lenty of VDI solutions do not need any end point infrastructure except for broadband internet access.However,many vendors require a thin client infrastructure simply for generating a rich end user experience. This is the component which makes VDI experience a lot better than the existing Citrix or the terminal service experience. Thin clients do not have local storage or DLLs. They are just tools to find the remote virtual desktop hosted at the datacenter or the server farm. Most of them have inbuild extensions of connection brokers of Leostream, Provision or Vmware. Some of them even have IP phone capabilities and video accelerators to make use of the local graphic cards.Some of the popular thin clients are Wyse,Neostream, NEC etc..
Access and authentication layer is contacted immediately after a user provides his username and password. He is authenticated and permissions are granted using good old Kerberos, LDAP or Active Directory. This is the same for any client server application and VDI is no different here.
Display protocol is used to export the display from the server to the client.Mostly it is RDP,VNC or Citrix ICA. While the processing happens at the server the display is exported to the thin client.
Connection Brokering is the industry’s most competed layer. There are a dozen of vendors fighting all out to conquer this layer.This component connects the end client to the corresponding VM running on the remote server.It needs to consider things like 1) server load 2) traffic 3) latency 4) bandwidth 5) permissions etc..VMware recently acquired Propero and Citrix already has a brokering application.Some of the other players are Provision,Chip PC, Leostream,Sun etc..
Application Virtualization solutions from Microsoft SoftGrid,Symantec SVS and thinstall are the most popular ones. These virtualize registry, filesystem and everything thats needs for an application to run. The application is streamed to the client from the server and they execute it from the client sandbox present at the end point. The calls to the OS are smartly redirected through the sandbox.This way the client is completely unware of the application running on it.
Virtualization infrastructure is the layer which manages the health of the virtual machines, their redundancy,load, maturity etc..VMware and Provision networks have tools in this layer.The tools act as a “mother” to the virtual machines monitoring them closely for their well being.The VMware product is called Virtual Center and there are also vendors like Veeam and Virtugo who offer similar solutions.
Virtualizd Guest OS remains our good old Windows XP/Vista which are hosted at the datacenter instead of local machines.
Virtualization Host:- This is the heart of the VDI solution. This is where the guest operating systems are hosted over bare metal boxes and managed like individual programs.This layer is dominated by Vmware with its flagship product ESX. But with the Citrix acquisition of Xen and Virtual Iron also doing very well, the status quo of Vmware may not be remain the same forever. But as of now, it looks like a smooth sail for some time to come for VMware.There are also other players like Parellels for Apple Mac users and KVM/Qemu for Open source enthusiasts. Of late a company called Qumranet has also developed a KVM based desktop virtualization solution.
Backup and Storage technology:- Companies like Veeam and Vizioncore sensed the opportunity for vm backup/storage operations and they have solutions in the areas for BC/DR and maintenance of Vms.
Storage:- IBM, Sun, Hitachi,EMC have been virtualizing SAN/NAS. To end users, storage appears as locally mounted disks while the storage is virtualised in the datacenter and managed through a storage management interface to the system administrator.
Thats all folks!. I ll keep you updated.
Your comments always rock!
