Quick start

The following example illustrates most of the elements found in a typical tcng configuration:

#include "fields.tc"
#include "ports.tc"

dev "eth0" {
    egress {
        // classification

        class (<$high>)
            if tcp_dport == PORT_HTTP;
        class (<$low>)
            if 1;

        // queuing

        prio {
            $high = class (1) {
                fifo (limit 20kB);
            }
            $low = class (2) {
                fifo (limit 100kB);
            }
        }
    }
}

The first two lines include files with definitions for header fields and port numbers. For details, see section .

The dev" and \verb"egress lines determine what is being configured, i.e. the egress (outbound) side of the network interface ``eth0''.

The configuration consists of two parts: the classification and the setup of the queuing system. In this example, we use a priority scheduler with two classes for the priorities ``high'' and ``low''.

Packets with TCP destination port 80 (HTTP) are sent to the high priority class, while all other packets (if 1;) are sent to the low priority class. Note that it is generally a good idea to finish a classifier with a selection rule that is always true.

The queuing part defines the queuing discipline for static priorities, with the two classes. Inside the high-priority class, there is another queuing discipline - a simple FIFO with a capacity of 20 kilobytes. Likewise, the low-priority class contains a FIFO with 100 kB.