The tcng language was originally designed to provide a clean and consistent way for describing the configuration of traffic control elements in the Linux kernel. Since then, tcng has been extended to allow - mainly for classification - much more abstraction from the underlying implementation, than originally planned.
So far, we have discussed the ``modern'' part of the tcng language, which gives access to all commonly used functionality, and which provides an abstract model of the classification process.
In the following sections, we will describe alternative means for configuring traffic control mechanisms, and syntactical constructs which are supported for backward compatibility.