For over ten years there has been on-going internal discussion in corporate IT departments surrounding the cost benefit to organizations of deploying a centrally managed thin-client hardware topology verses “fat client” or locally installed applications on PC’s. There was a time, about seven or eight years ago, when the argument against thin clients from a cost perspective was a futile endeavor. During this era of the late 90’s the cost of a PC was decreasing but a quality business class system ran $900 or more without a monitor.
Now with a solid, business class workstation priced at $700 or less, with a flat panel LCD display and Windows XP Pro, the cost benefit of a thin client environment must be weighed by factors that were considered unbeatable at the dawn of thin client computing. Some of these include: centralized administration, ease of deployment, license manageability and remote user access. Currently a thin client deployment using Microsoft RDP and Citrix components are far from being less expensive than the cost of a PC. I include Citrix in the equation verses standard Microsoft RDP because of the security, stability and flexibility ICA adds to the environment, such as the ability to publish individual instances of applications verses the entire desktop and the ability to overcome notorious printing issues.
One of the key costs of a Microsoft thin client deployment is the cost of running Windows 200x Terminal Server in “Application mode”. Once a Windows server is converted from “Administrative mode” each device or user that connects to the system will require a “Device” or “User” CAL (Client Access License). There’s a big difference in the two that must be taken into consideration when making the purchase from a Microsoft license reseller and setting up the terminal server. Here’s the difference:
- A Microsoft Terminal Server “User” CAL means that each domain user account that connects to a terminal server instance will permanently use a CAL. The user account can use this CAL to access any MS Terminal Server instance. This CAL can only be released from it’s bind to the user account via a call to Microsoft Licensing Support and usually only twice per CAL according to MS policy.
- A Terminal Server “Device” CAL is one that permanently ties itself to a specific workstation or hardware device (i.e. thin-client) by binding to the MAC address of the network adapter for that device. The device can use this CAL to access any MS Terminal Server instance. This CAL can only be released from it’s bind to the device via a call to Microsoft Licensing Support and usually only twice per CAL according to MS policy.
A ideal example of when to use per Device CAL’s would be in a call center environment. Several different users will sit down to the same workstations on multiple shifts. With three shifts you would have to invest in three times as many user CAL’s as Device. Alternatively a good use of per User CAL’s is for remote users of applications who may not always use the same device to access the terminal server environment.
The cost of a User CAL and Device CAL are the same. Since they tie themselves to the user account or device accessing a terminal server they are termed “non-concurrent” licenses. Generally these run approx. $70 per user for a small to medium business depending upon your relationship with your license reseller. I will not include the cost of the server OS itself because it will be assumed that a Microsoft 200x server will be in the environment regardless or architecture. However a terminal server will be more expensive than a standard file and print server due to hardware requirements. A difference of around $2000 on average.
On top of the required Microsoft licensing there are the required Citrix Presentation server licenses. Unlike the Microsoft licenses Citrix licenses are “concurrent”, meaning they do not tie to users or devices. They are pooled on a licensing server and checked out each time a user logs in to a Citrix server or “Farm”, which is a group of MS terminal servers running Citrix in a load balanced configuration for application scalability. Each Citrix license (not termed a CAL) currently costs approx. $220 per user for the standard edition of Citrix Presentation server 4.0 and $400 per user for the advanced edition which supports the load balancing scalability feature. The standard edition only supports the connection of users to one Citrix terminal server instance. One modern server with two processors and 2Gb of memory minimum can support up to 30 concurrent users (15 per processor by Citrix long running standards).For the sake of this cost analysis I will assume 30 Citrix users. I am not going to assume corporate application licensing costs or compatibility with a thin client environment because the variables are too numerous. It would be up to experienced administrators to make this assessment on an individual basis.
Total Cost Breakdown:
$320 x 30 = $9600 – ICA compatible thin client device from Wyse or HP.
$120 x 30 = $3600 – 17″ flat panel LCD monitors
$70 x 30 = $2100 – Per User or Device Terminal Server CAL’s.
$220 x 30 = $6600 – Concurrent “standard” Citrix Presentation Server 4.0 licenses.
$2000 – Additional server hardware cost for multi-session thin client support.
Approximate total for Citrix ICA thin client deployment = $27500.00 or $916.66 per user.
Approximate total for Workstation deployment = $21000.00 or $700 per user.
Clearly the base cost of hardware and OS licensing is no longer the primary benefit in selecting a thin client environment. But when additional factors, such as less desktop hardware support, are taken into consideration there are many benefits to a thin client environment including those I mentioned earlier. By no means does the falling prices of PC’s mean the end of remote application deployment. In fact I think it just means that now we’ll be able to have the best of both worlds as the PC’s replace the thin client hardware devices and remote application technologies take hold to provide reliability and ease of administration through centralized management.
And to those who think I’m forgetting to take network connectivity into consideration as a reliability factor I will only remind you that almost all corporate applications in use today require access to network files or SQL data to function any way. So never, under any circumstances, regard network reliability as anything less than an absolute necessity.
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