Tc command examples

What is the tc command?

The tc command reads one or more English-language files. If no file is specified or the - (minus sign) flag is specified as the last parameter, standard input is read by default. The standard output of the tc command is intended for a Tektronix 4015 (a 4014 terminal with ASCII and APL character sets).

How to use tc command in Linux?

Tc is used to configure Traffic Control in the Linux kernel. Traffic Control consists of the following: SHAPING When traffic is shaped, its rate of transmission is under control. Shaping may be more than lowering the available bandwidth - it is also used to smooth out bursts in traffic for better network behaviour.

What is tc tool?

Linux offers tools for managing and manipulating the transmission of packets. The Linux Traffic Control (TC) subsystem helps in policing, classifying, shaping, and scheduling network traffic. TC also mangles the packet content during classification by using filters and actions.

What is tc in Linux kernel?

tc (traffic control) is the user-space system administration utility program used to configure the Linux kernel packet scheduler. Tc is usually packaged as part of the iproute2 package.

How to use tc in Ubuntu?

What is qdisc in tc?

qdisc. Simply put, a qdisc is a scheduler (Section 3.2). Every output interface needs a scheduler of some kind, and the default scheduler is a FIFO. Other qdiscs available under Linux will rearrange the packets entering the scheduler's queue in accordance with that scheduler's rules.

What is tc Netem?

NetEm is an enhancement of the Linux traffic control facilities that allow one to add delay, packet loss, duplication and more other characteristics to packets outgoing from a selected network interface.

How to add network delay in Linux?

To add a fixed delay to packets, we can use the delay option on netem. Concretely, we can run the tc qdisc add command with the netem delay option. The command above specifies a netem delay option. Additionally, we've specified a fixed delay of 100ms.

What is CTL in command line?

The ctl part stands for control . You use it to control RabbitMQ for general administrative/operator tasks.

What is QoS in Linux?

Quality of Service (QoS)

What is Pfifo_fast?

pfifo_fast is the default qdisc of each interface. Whenever an interface is created, the pfifo_fast qdisc is automatically used as a queue. If another qdisc is attached, it preempts the default pfifo_fast, which automatically returns to function when an existing qdisc is detached.

How does netem work?

netem provides Network Emulation functionality for testing protocols by emulating the properties of wide area networks. The current version emulates variable delay, loss, duplication and re-ordering. Netem is controlled by the command line tool 'tc' which is part of the iproute2 package of tools.

What is T State in Linux?

Stopped State (T) From a running or runnable state, we could put a process into the stopped state (T) using the SIGSTOP or SIGTSTP signals.

What is CLS command in Linux?

In computing, CLS (for clear screen) is a command used by the command-line interpreters COMMAND.COM and cmd.exe on DOS, Digital Research FlexOS, IBM OS/2, Microsoft Windows and ReactOS operating systems to clear the screen or console window of commands and any output generated by them.

What is TC NetEm?

What is Pfifo_fast?

What is eBPF in Linux?

eBPF is a revolutionary technology with origins in the Linux kernel that can run sandboxed programs in a privileged context such as the operating system kernel. It is used to safely and efficiently extend the capabilities of the kernel without requiring to change kernel source code or load kernel modules.

How does iproute2 work?

iproute2 is usually shipped in a package called iproute or iproute2 and consists of several tools, of which the most important are ip and tc. ip controls IPv4 and IPv6 configuration and tc stands for traffic control. Both tools print detailed usage messages and are accompanied by a set of manpages.

How to add network delay in Linux?

How does FQ_Codel work?

FQ_Codel uses a stochastic model to classify incoming packets into different flows and is used to provide a fair share of the bandwidth to all the flows using the queue. Each such flow is managed by the CoDel queuing discipline. Reordering within a flow is avoided since Codel internally uses a FIFO queue.

What is QoS in Linux?

Quality of Service (QoS)

What is the IP command in Linux?

The ip command is a Linux net-tool for system and network administrators. IP stands for Internet Protocol and as the name suggests, the tool is used for configuring network interfaces. Older Linux distributions used the ifconfig command, which operates similarly.

What is RPF in Linux?

This command determines whether incoming packets with a source address that cannot be routed by that interface are accepted and processed.

Why is BPF used?

The Berkeley Packet Filter (BPF) is a technology used in certain computer operating systems for programs that need to, among other things, analyze network traffic. It provides a raw interface to data link layers, permitting raw link-layer packets to be sent and received.

What is PnP in Linux?

Plug and Play (PnP) is a standard for peripherals that allows them to be configured by software, e.g. to assign IRQs or other parameters. No jumpers on the cards are needed; instead, the values are provided to the cards from the BIOS, from the operating system, or using a user-space utility.