Thin-Client Computing
	Detailed Overview with full Pro's & Con's

Thin-Client Computing cont.

As previously discussed Thin-Client servers are available from both Microsoft and Citrix. Below is a brief comparison between the two available technologies

Microsoft Terminal Services Citrix Metaframe Microsoft Terminal Services (Windows 2000) is a thin-client solution in its own right. Citrix Metaframe is a set of extensions and enhancements to the Microsoft Terminal Services product. Microsoft Terminal Services servers cannot be easily grouped together and actually require clustering technology to achieve this. Citrix Metaframe provides a method of grouping multiple servers together, in to a "Server Farm" so that it can be easily viewed as a single resource. The server farm concept also allows for automated load-balancing so servers all share the user/processing load. Microsoft Terminal Services is only capable of delivering a complete Windows Environment (e.g. Start Menu, My Computer etc.). Citrix Metaframe has the option to just deliver single applications, which appear to users as though they are running locally), giving seamless integration between client-server & thin-client environments. Microsoft Terminal Services does not support access to local floppy disks, hard drives, etc. (if users are connecting from PCs) from within the thin-client session. Citrix Metaframe allows users to access the floppy drive in a PC, local Hard Drives etc. This can be most useful for users with equipment that is capable of working without the Thin-Client server (e.g. laptops with local installations of Microsoft Office) as any documents etc. created are seamlessly accessible. Microsoft Terminal Services does not allow users to use printers attached locally to the device they are connecting from (e.g. LPT1) Citrix Metaframe allows users to print to locally connected printers (LPT1 etc.). This is most beneficial for users working from home for example where there are no network printers available. Microsoft Terminal Services does not support "automatic client printer creation" "Automatic Client Printer Creation" is a feature of Citrix Metaframe whereby if you connect from a PC any printers you have locally configured will automatically be created within the Thin-Client environment. Microsoft Terminal Services requires a specific piece of client software to be installed and configured before users can connect to the server Citrix Metaframe provides a method of launching a connection from a Webpage without any specific software being installed before hand. The process of attempting to launch the connection can be made to install the required software the first time it is run.

For a full review of the differences between Microsoft Terminal Services (referred to as RDP in the linked document) and Citrix Metaframe (referred to as ICA in the linked document) please visit www.microsoft.com/windows2000/server/evaluation/features/rdp.asp.

Pro's and Con's of Thin-Client Technology

The Pro's and Con's of Thin-Client computing discussed below are in relation to a multi-site organisation using applications that require access to a centralised database(s), File server(s) and other resource(s).

Pro's

Calculable Bandwidth requirements for W.A.N. links.   Thin-Client computing does not transfer any data to the client machine, it is simply 'painting' the screen and receiving input. As a result, a fixed amount of bandwidth is required per client, regardless of the applications in use or the working practices employed. In a traditional network where data is transferred between sites it is far more difficult to calculate the bandwidth requirement for the W.A.N. links. The bandwidth requirements are also more likely to change regularly as working practices, applications in use and number of clients change. Cost savings due to reduced bandwidth requirements for W.A.N. links   The amount of network bandwidth required to 'paint' a Thin-Client's screen and feedback input to the server is far less than is required in a traditional W.A.N. where actual data is transferred between host machine and client. In this traditional W.A.N implementation the actual amount of bandwidth required varies depending on the applications being used, however the bandwidth requirement can be up to ten times that of the thin-client Centralised Application Deployment   As all users log on to a single server, or group of servers, and run the applications on the server(s) any application configuration or updates need only be done on the thin-client server(s) as opposed to updating each individual client PC, which would be required in a traditional W.A.N. implementation. User Environment Management   As with Microsoft Windows installed on a PC, the thin-client environment can be restricted to prevent users from changing key settings, while still allowing them to customise the look and feel of their working environment. These restrictions decrease support costs and increase the overall network security as they can be extended as far as preventing users introducing data via floppy disk/CD-ROM etc. True Hot-Desk capabilities   Where users have the requirement to move around either from site-to-site or within sites they will retain their working environment and personal settings. Since they will still be connecting to the thin-client server their applications are delivered to them irrespective of the method of connection (LAN/WAN or Dialup). Indeed a major performance advantage is gained by remote users logging in to Thin-Client machines using standard Dialup modem connections. Working from home is a realistic option. This increases the flexibility of the organisation and reduces the support and licensing costs of installing applications on machines where they are not always required. ·Reduced Support costs/response-times   As thin-client computing is based around the concept of sending/receiving input and output only to the client machine this allows shadowing to take place. Shadowing is the process by which input/output is redirected to an administrator's machine as well as to the original client machine. This allows administrators to be "sat" at any client machine logged on to the thin-client server without leaving their desk. Desktop support can be performed with instantaneous response times. Where users are located on remote sites this shadowing technology removes the need to travel for all but the most serious of problems encountered (generally hardware issues) and can remove any requirement for I.T. support personnel to be located in remote offices. Reduced Client Hardware replacement costs   As all of the application processing and data manipulation is performed by the thin-client server when using thin-client computing the hardware specification of the client machine is in many ways irrelevant. This means that older PCs can be utilised as thin-clients without the need for any rolling PC replacement program, and therefore the ongoing cost of ownership for the network as a whole is reduced.

Con's

Higher Server hardware cost   Since all users are in effect processing data on the same server, the server required to run a Thin-Client solution is of a much higher specification than one serving a networks file and print or single application needs. This higher cost is negligible when compared to the alternative of replacing possibly hundreds of PC's on a regular basis and providing Bandwidth at remote sites capable of supporting Thick client solutions. Administration training   The introduction of a new operating system into any organisation large or small means the introduction of a new set of skills for the IT support staff. Many of the core networking and administration skills are transportable across operating systems and those specific skills required can be learned over a period of time. Reduced support visits   While on the face of it this may appear to be a positive feature, some users are comforted by the fact that IT support staff visit site. With Thin-Client computing these visits become less frequent and in some cases not required at all. However this is a matter of educating the users to not expect what is in effect only a comfort blanket since remote support is more practical cost effective and efficient.