Terminal Services in Windows Server 2003 provides new options for application deployment, more efficient access to data over low bandwidth, reuse of older hardware, remote management, and other tasks.

Microsoft Terminal Services allows you to bring your applications to a single server for use by users anywhere in the world. For example, instead of deploying database or accounting software on all desktops, it can simply be put on a server and remote users can log on and use it across the internet. This makes upgrades, troubleshooting, and software management much easier by centralising it at the server.

A thin client, sometimes called a lean client, is a low-cost, centrally-managed computer devoid of CD-ROM players, diskette drives, and expansion slots.

Some advantages of thin clients:

• Lower IT admin costs. Thin clients are managed almost entirely at the server. The hardware has fewer points of failure and the local environment is highly restricted providing protection from malware.
• Easier to secure. Thin clients can be designed so that no application data ever resides on the client (it is entirely rendered), centralising malware protection.
• Lower hardware costs. Thin client hardware is generally cheaper because it does not contain a disk, application memory, or a powerful processor.
• Lower Energy Consumption. Dedicated thin client hardware has much lower energy consumption than most thick client PCs.
• Hostile Environments. Most devices have no moving parts so can be used in dusty environments without the worry of PC fans clogging up and overheating and burning out the PC.
• Less network bandwidth. Since terminal servers typically reside on the same high-speed network backbone as file servers, most network traffic is confined to the server room. In a fat client environment if you open a 10MB document that's 10MB transferred from the file server to your PC. When you save it that's another 10MB from your PC to the server. When you print it the same happens again - another 10MB over the network to your file server and another 10MB back to the printer. This is highly inefficient. In a thin client environment only mouse movements, keystrokes and screen updates are transmitted from/to the end user. Over efficient protocols such as ICA or NX this can consume as little as 5Kbps bandwidth.
• More efficient use of resources. A typical thick-client will be specified to cope with the maximum load the user needs, which can be inefficient at times when it is not utilised. In contrast, thin clients only use the exact amount of resources required by the current task - in a large network, there is a good probability the load from each user will fluctuate in a different cycle to that of another user (i.e. the peaks of one will more than likely correspond, time-wise, to the troughs of another.
• Simple hardware upgrade path. If the peak resource usage is above a pre-defined limit, it is a relatively simple process to upgrade the server (be it power, processing, storage), boosting resources to exactly the amount required. The existing units can be continued in service alongside the new, whereas a thick client model requires an entire desktop unit be replaced, resulting in down-time for the user, and the added problem of disposing of the old unit.