A TDI driver basically sets the standard for the application programming interface or API used in low level protocols like TCP/IP. The name is actually short for Transport Driver Interface. With this type of interfacing, you can set the methods which will be used in communications protocols like sending and receiving data, detecting disconnections, and reading data streams among other functions. As a network administrator, you need to become familiar with this driver interface because it supports most Windows-based transport providers. It also supports features like asynchronous operations and provides open addressing system. TDI can allow submission of private requests from clients. Such requests will be transported to specific drivers that can comprehend the actions requested.

But a more important function of a TDI driver is filtering data from a network. True, if you are using a Winsock LSP, you can enjoy higher ability to manipulate communication protocols at stream level. But operating with Winsock LSP is not recommended if your applications will need inspection at the packet level. For this particular situation, it is better to perform filtering using TDI implementations. In other words, if LSP (Layered Service Provider) cannot work, it is just wise to consider other types of filtering interfaces like TDI.

Using a TDI driver can help you greatly if you have been tasked with developing a formidable firewall. Come to think of it, Microsoft has developed this driver interface with enhanced flexibility in mind. It has more functionalities than other types of interfaces like NetBIOS and even Winsock. For instance, a direct interface between Windows 2000 transport providers and TDI is allowed. A direct access between the transport and the driver interface should enhance the overall throughput of the network, which can be a crucial function in a time-sensitive network access. This permits this type of driver interface to offer more consistent transport protocol systems.

On the downside, many experts say that transport driver interface will no longer get support in subsequent operating systems after Windows Vista. Hence, the usage of TDI driver may also dwindle. Add to that the fact that this type of driver interface may perform with significantly downgraded capacity when used for intercepting TCP/IP traffic that passes to and from clients that use the network programming interface called Winsock Kernel or WSK for short. But come to think of it, being able to filter TCP/IP traffic, which many now considered as legacy protocols, is still an impressive feat.