ucfq

ucfq [ options ] dev device [ qlen length ]

dev device
    Specifies the network device to configure the UCFQ on. device is the name of the network interface (e.g., eth0, wlan0).

qlen length
    Sets the queue length for the specified device. length is the desired queue length in packets. A larger queue can absorb bursts of traffic but also increase latency.

help
    Displays help information about ucfq command usage.

The ucfq command is a utility for managing the UC Berkeley Fast Queue (UCFQ) packet scheduler in the Linux kernel. UCFQ is a high-performance, low-latency queuing discipline designed to provide fair bandwidth allocation among different flows. ucfq allows users to inspect and modify the UCFQ parameters associated with network interfaces. This includes setting the queue length, viewing flow statistics (like packet counts and bytes transferred), and configuring parameters that control how flows are classified and scheduled. Essentially, it acts as a control interface, offering fine-grained control over the UCFQ scheduler's behavior. It's typically used in advanced networking scenarios where precise traffic shaping and quality of service (QoS) are critical. Its usage involves understanding networking concepts such as packet scheduling, queuing disciplines, and traffic shaping.
It's important to note that working with queueing disciplines like UCFQ requires root privileges and a strong understanding of network configuration.

This command requires root privileges to execute. Incorrect configuration can severely impact network performance. The UCFQ scheduler and ucfq command may not be available in all Linux distributions or kernel versions. Familiarity with network traffic shaping and queuing disciplines is essential before using this command.

While ucfq primarily focuses on setting queue length, it works in conjunction with other traffic control mechanisms (like tc) to classify traffic into flows and apply specific scheduling policies using UCFQ. ucfq alone doesn't provide tools for flow classification, but it defines a base queue.

tc(8), ip(8)