Linux tc bandwidth limit example. 1) and had been trying to ...
Linux tc bandwidth limit example. 1) and had been trying to use the following rules: tc qdisc add dev tun1 root handle 1: cbq avpkt 1000 bandwidth 3000mbit. This article would be a howto on using linux tc with kvm/lxc guests. 10) also has the option to limit the bandwidth using the rate option: tc qdisc add dev lo root handle 1:0 netem delay 10ms rate 1mbit limit 1000. Bandwidth Shaping Bandwidth shaping is one of the most common use cases for Qdiscs. 1) I have apache. 11 Limiting network resources based on some criterias is the subject of QoS. ) is to […] The ‘tc’ command in Linux is a powerful tool for traffic control. Traffic Control consists of the following: SHAPING When traffic is shaped, its rate of transmission is under control. In this article, we will use tc to limit the egress network bandwidth rate on a specific network interface. With TC, you can control the flow of data packets, limit bandwidth, introduce delays, and ensure that critical traffic gets the necessary resources. My version of netem (Ubuntu 13. I'm having an issue with a bandwidth script that I've been using for a while to limit the outgoing bandwidth on a port. ‘tc’ can be used to set bandwidth limits, prioritize traffic, and even manage traffic bursts. The following limits the bandwidth correctly but does not I'm trying to limit the incoming and outgoing bandwidth with latency through a specific port using TC but I can't get it to work 100%. 10. In other words, if there are 100 Overview of Traffic Control (tc) tc is a powerful utility that allows you to configure traffic control in the Linux kernel. The machine I want to limit the traffic is 192. Let’s look at an example: tc qdisc add dev eth0 root handle 1:0 netem delay 100ms tc qdisc add dev eth0 parent 1:1 handle 10: tbf rate 256kbit buffer 1600 limit 3000 The first command sets up our root qdisc with a handle named 1:0 (which is equivalent to 1: since the minor number of a qdisc is always 0) and a packet delay of 100ms. The iproute2 package installs the tc command to control these via the command line. I've 10Mbps server port dedicated to our small business server. Creating a 256kbit/s TBF" tc qdisc add dev eth0 handle 1:0 root dsmark indices 1 default_index 0 tc qdisc add dev eth0 handle 2:0 parent 1:0 tbf burst 20480 limit 20480 mtu 1514 rate 32000bps How is the 256K bit/s rate calculated? In this example, 32000bps = 32k bytes per second. I'm new at linux and my goal is to create a simple traffic control for "eth0" or "lo" using the tc command (or other commands like ifconfig or iptables, but i don't think i need them). Traffic Control consists of the following: SHAPING When traffic is shaped, its rate of transmission Some answers on this topic can be find under Limiting interface bandwidth with tc, Limit network bandwith for an IP, How to limit network bandwidth, or Rate limit network but allow bursting per TCP connection before limiting. Practical examples for shaping and managing network traffic. 6. mtu is also known as minburst. Traffic Prioritization Trickle is a network bandwidth shaper tool that allows us to manage the upload and download speeds of applications in Linux systems. How do I limit bandwidth allocation to http service 5Mbps (burst to 8Mbps) at peak times so that DNS and other service will not go down due to heavy activity under a Linux operating systems? In the realm of Linux networking, the `tc` (Traffic Control) command is a powerful tool that allows system administrators and network engineers to shape, police, and prioritize network traffic. TC limiting : Helps to set maximum upload/download speed limit to your linux server/pc's selected network interface. I want to limit the max download speed to 1Mbps for every device which uses this gateway. I am trying to understand the Linux command tc. Standard practice when transmitting packets over a medium which may block (due to congestion, e. Here is a sample set-up, I left it in Mbit format but you can change the rate measure to kbps. 168. 2. Learn how to configure Quality of Service (QoS) on GNU/Linux using the tc command. We have been able to use 'tc' (traffic control) in Linux and dummynet in FreeBSD to inject delay (latency) with predictable behavior. Advanced Configuration tc offers many more options for precisely controlling and monitoring network traffic. And there you have it, a few examples of using the tc command to shape network traffic on your Linux machines, so you can better test your network-aware applications. Shaping occurs on egress. TC(8) Linux TC(8) NAME top tbf - Token Bucket Filter SYNOPSIS top tc qdisc tbf rate rate burst bytes/cell ( latency ms | limit bytes ) [ mpu bytes [ peakrate rate mtu bytes/cell ] ] burst is also known as buffer and maxburst. I've been reading up on netem and using the tc command, but it's still all a bit over my head. 0/0 action police rate ${LIMIT} burst ${LIMIT} I'm using tc with kernel 2. For example, you can create complex filters that limit bandwidth only for specific types of traffic or applications, or use different queuing disciplines such as HTB (Hierarchical Token Bucket) for even more precise traffic control. Aug 24, 2010 · In order to limit bandwidth of individual IP addresses, I have been TC with HTB. When I ping google, the In my linux router: interface eth1 total bandwidth is 1gbit I want to divide 1140kbit to GroupA, divide 150kbit to GroupB Set users 10. This low-level capability can be used for use cases such as implementing quality of service controls to simulating networking scenarios that can be helpful for test cases and validations of application deployments. For example, you can limit the bandwidth used by a peer-to-peer application to ensure that other critical applications have enough bandwidth. And for 10 kbytes per second: iptables -A OUTPUT -m limit --limit 10kb/s -j ACCEPT Example 1 We will use Linux HTB to set bandwidth on the h1--r or h2--r links, so that two flows arriving at h2 have two different bandwidth limits. tc filter add dev ${IF_INET} protocol ip ingress prio 2 u32 match ip dst 0. On a Linux system I want to throttle the network to the following specifications a latency of 250 ms a maximum bandwidth of 1 MB/s and I tried to run sudo tc qdisc add dev eth0 root netem delay 2 How to restrict the incoming bandwidth for an entire subnet? How to set bandwidth limits on incoming packets for a whole subnet? I want to limit outgoing traffic per IP address. Anything is fair game. 38. As part of the Linux Nov 14, 2025 · Linux Traffic Control (TC) is a powerful tool that allows system administrators and network engineers to shape, police, and prioritize network traffic. This got me a measured bandwidth of 113 Kbits/sec. This means you can control the throughput, the data amount over time only. I have a gateway whose OS is Linux. 8 for traffic shaping. 1. - limit-tc. How I am a newbie network engineer. Now, my intention is to limit the bandwidth PC2 can use to send the incoming data from PC1 to PC3. Assume my downlink bandwidth is 100 Mbps. Then, I 5 We have a network product that runs on Linux and needs to be tested in reduced bandwidth networks. Dec 17, 2024 · The ’tc’ command is a utility in Linux that allows system administrators to configure network traffic control settings. I'm not sure if I've done it correctly. The Linux kernel's network stack has network traffic control and shaping features. To set an outgoing bandwidth limit of 4096 kbps. You can use an HTB Qdisc to divide the available bandwidth among different applications or users. First i added the command: iptables -t mangle -A OUTPUT -p TC, the Traffic Control utility, has been there for a very long time - forever in my humble perception. Use the following command to verify the setting on your network card # tc qdisc show dev eth0 qdisc pfifo_fast 0: root refcnt 2 bands 3 priomap 1 2… I know I can add latency to an interface using this command: # tc qdisc add dev eth0 root netem delay 50ms In addition to latency, I want to limit the bandwidth of this interface to 100kbps. The server also act as a backup DNS server and I'd like to slow down outbound traffic on port 80. It is still (and has ever been if I'm not mistaken) the only tool to configure QoS in Linux. Apr 14, 2022 · I am new to Linux and tc command and I have been looking to limit bandwidth per connection using tc. 0/24 has a individual upload limit of 10Mb/s that may not be exceeded. On client (1. py on h3. I want to limit bandwidth-speed of internal ip-addresses (like 10. Data will be received using dualreceive. According your description for 50MB/hr you would need to set something like 125kBps for your rate. I made a simple network, consisting of two hosts H1, H2 and a switch S1 connecting them by using Mininet. 5. TBF is As tc utilizes the built in (or modular) queuing disciples in the kernel it the simplest/best way of limiting bandwidth on a per user basis. to a network-interface/Docker-container (veth). This command provides the tools for simulating various network conditions, managing bandwidth allocations, and monitoring active traffic control policies on network interfaces. Shaping Linux Traffic with tc Shaping Linux Traffic with tc tc enables configuring Traffic Control in a Linux host. Summary tcconfig is a tc command wrapper. I was planning on doing this by setting a large buffer on PC2 with a delay on fetching the packets from the buffer to simulate a slower link. For example 800ms delay and 1mb/s. 21. I have looked around extensively, and out of the solutions I can find, either it's a limit placed on an interface, or it's a vaguely described iptable setup that seems to have only been tried on CentOS 6. We set the bandwidth limit of 1Mbps for the default class, which, in effect, becomes the default bandwidth for wireless. To send data, we will use the C sender command. Tc is used to configure Traffic Control in the Linux kernel. Limit bandwidth works, adding delay works, but when shaping both bandwidth with delay, the achieved bandwidth is always much lower than the li Linux - Networking This forum is for any issue related to networks or networking. Shaping may be more than lowering the available bandwidth - it is also used to smooth out bursts in traffic for better network behaviour. Kubernetes CNI bandwidth plugin is also realized by tc, and can limit the bandwidth of pods with the following annotatiton. It is one strategy to address problems caused by Network congestion. Traffic Control is the umbrella term for packet prioritizing, traffic shaping, bandwidth limiting, AQM (Active Queue Management), QoS (Quality of Service), etc. Playing around with those parameters didn't change that much until I noticed that adding a value for mtu changes things drastically: # tc qdisc add dev bond0 root tbf rate 1mbit limit 10k burst 10k mtu 5000 resulted in a measured bandwidth of 1. There is a good How-to about advanced routing techniques and traffic control on Linux by Bert Hubert. The target audience for this HOWTO is the network administrator or savvy home user who desires an introduction to the field of traffic control and an overview of the tools available under Linux for implementing traffic control. 8. 5, and also the script is being run from 192. For example I have a network interface eth0, having 1Gbps of bandwidth. Since tc uses bps = bytes per second. 00 Mbits/sec. And on proxy machine I want to limit speed by using tc. Here are some useful links: As a simple example, in order to limit bandwidth of individual IP addresses stored in CLIENT_IP shell variable, with limitations like the following: Commands below would suffice: Nov 4, 2015 · I am trying to limit the maximum bandwidth for a range of ports (collectively) using tc. There are several different ways to control user traffic on Linux systems. Whether you're looking to manage bandwidth, reduce latency, or ensure fair distribution of network resources, `tc` provides a comprehensive set of features to achieve these goals. Mar 18, 2024 · With tc, we can control and simulate various network configurations in general. The router is a Motorola SurfBoard modem with a few routing capabilities and firewall. But when we try to throttle the bandwidth with either of these, it does not seem to have much effect. It worked fine at the beginning until I wanted to change the outgoing port s I have three machines: client, server and proxy. I discovered that i can use TC and IPTABLES for limiting bandwidth on SSH per linux user. Now we make one more class, 1:2, and set its bandwidth to 400 kbps. I want to limit the whole network interface to 1Mbps each destination IP Ad 8 Based on this section of the Linux Advanced Routing & Traffic Control HOWTO, I can't get tc to limit the network speed in my computer. 5, 10. Here is an example for 10 packets per second: iptables -A OUTPUT -m limit --limit 10/s -j ACCEPT. Here is a working example of what I am doing for each ip (looking to simplify procedure if possible): These steps only need to be performed once: Create initial HTB qdisc: 3 I am running CentOS 7 on my VPS and I would like to limit bandwidth on a specific port. Jan 11, 2026 · Traffic Control (tc) is Linux's powerful framework for managing, shaping, and controlling network bandwidth at the kernel level. For example, set global limit for 192. Traffic controller in Linux for altering Network Delay and Bandwidth About Traffic Control Traffic control (tc) is a very useful Linux utility that gives you the ability to configure the kernel … Tc is used to configure Traffic Control in the Linux kernel. 158, 10. Below is the script: The above script runs fine, but the bandwidth on those ports is not limited. Make it easy to set up traffic control of network bandwidth/latency/packet-loss/packet-corruption/etc. 6 to GroupB Each user has no On Linux Traffic Queuing Discipline attached to a NIC can be used to shape the outgoing bandwidth. 0/0 action police rate ${LIMIT} burst ${LIMIT} tc filter add dev ${IF_INET} protocol ip ingress prio 2 u32 match ip src 0. Routing, network cards, OSI, etc. Limit bandwidth, burst rate and max latency: sudo tc {{[q|qdisc]}} {{[a|add]}} dev eth0 root tbf rate {{max_bandwidth_mb}}mbit burst {{max_burst_rate_kb}}kbit latency {{max_latency_before_drop_ms}}ms This post is not a tutorial on linux traffic control. I've managed to put together this command to control the latency which seems to work, but I'm not even sure if that only handles the outgoing latency or both: I want to throttle bandwidth and add delay to a network interface to simulate satellite communication. It allows administrators to configure the kernel’s packet scheduler to control the ingress and egress of network packets. When I check the status, I cannot find any filter for those ports: match 13880000/ffff0000 at 20. To set an incoming bandwidth limit of 512 kbps. Discover 2 easy methods to limit bandwidth on Ubuntu and Debian using Wondershaper and Traffic Control (TC). This HowTo will help you understand and set up traffic control on your router. DESCRIPTION top The Token Bucket Filter is a classful queueing discipline available for traffic control with the tc(8) command. Simple and step-by-step. sh In particular "Example 9. Please refer to lartc or the traffic control howto. The goal of this article is to show how to shape the traffic by using queueing disciplines. 1) I have simple script, which using wget, on server (2. Then we will change one of the bandwidth limits while testing is going on. It can be used to shape, schedule, police, and drop traffic, providing fine-grained control over network bandwidth. 0/24 to 100Mb/s and each source ip within 192. By default, Linux uses pfifo_fast as the queuing discipline. This blog post will How to apply a bandwidth or latency limitation to network interface or protocol? How to configure latency on Ethernet interfaces in a test environment to simulate production? How do I use the tc traffic control command and qdisc (queueing disciplines)? How to limit bandwidth for a single protocol like NFS? We found excessive use of bandwidth, how can we restrict it? How can a QoS (Quality of Learn the ins and outs of using Linux traffic control (TC) utility; this post covers packet loss , delay and much more. 1 It is possible to limit incoming and outgoing bandwidth and latency with tc (Traffic Control). tc is a command or subsystem that configures a qdisc (queueing discipline) that queues packets and controls traffic before the kernel sends them to the network interface. 0. g. ucsij, w5l8v, t5cfeg, i7fn4, lid3h, fu02as, ufk0, cy440, fydz, ulf6,