Questions tagged [tc]

Tc is used to configure Traffic Control in the Linux kernel.

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19 views

Can TC rules persist beyond a reboot? Where?

I am trying to determine whether rules put in place using tc persist beyond a reboot (I do not believe they do by default), and whether there is any way to cause them to persist, or if the best you ...
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tc qdisc add dev eth0 handle ffff: ingress only relaying Multicast/Broadcast traffic from physical interface, need to mirror all traffic… any idea

I have two linux machines running debian 10, they both have dual interfaces. I have built a tunnel between the two machines and mirrored traffic from host1 collection interface to tunnel on host 2. I ...
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48 views

Connection reset by peer errror when delaying network response packets

Client's side code written in redis-plus-plus int main(){ auto redis = Redis("tcp://192.168.122.50:6379); sleep(5); int ep = 100; while(true){ cout<<"==============...
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279 views

Linux tc filter add - errors RTNETLINK answers: Operation not supported

I'm working on the network simulation to create some traffic on specific ports , and trying to inject the network delay. I'm using the linux tc utility to do this operations. So i'm new to the tc ...
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6 views

set asymmetric bandwidth on an interface

I'm coding a simple application using docker-compose and docker networks (images based on ubuntu). One of my services is a client with a network interface given from docker. All my services are on my ...
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28 views

Signification of TC (Trafic Control) backlog counter

I try to understand the signification of the counter backlog from the TC stats. Example : tc -s class show dev eth0 class htb 1:1 root rate 10Mbit ceil 10Mbit burst 5000b cburst 5000b Sent 602228374 ...
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21 views

Some doubts about traffic control

I am performing an experiment of network bandwidth limitation on my ubantu machine. Many views believe that tc (traffic control) cannot limit the inbound bandwidth, and point out that it needs to be ...
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1answer
158 views

Forcefully enable fq_pie

I am very interested in setting up fq_pie queue discipline for TCP congestion control. If I write net.core.default_qdisc = fq_pie to /etc/sysctl.d/90-override.conf, it should enable fq_pie on latest ...
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190 views

Installing wondershaper on Debian 10

# apt-get install wondershaper # wondershaper wlan0 24000 16000 Now what?! How can I tell if it's running? How can I get it to start automatically after a reboot? (And configure it.) None of the ...
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ESFQ is not control the upload

I am using IMQ and Iptables to control the packages outcome from my LAN using ESFQ, but it is not work at all. How I can control the upload of my LAN, I know that others systems like Mikrotik, has its ...
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32 views

How does a htb qdesc tree handle bandwidth overallocation?

let's say I have a simple htb hierarchy (See man 8 tc-htb) set up where the total bandwidth specified for child htb classes exceeds the total bandwidth specified for the root htb class: tc class add ...
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137 views

wondershaper bandwdith limit per ip

Does this command allows us to download speed 512kpbs for each connected devices? or let say if two devices connected then they get only 256kbps each or 512 kbps each ? sudo wondershaper wlan0 512
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How to set priority of network traffic for services using systemd?

I want to be able to specify the priority for all incoming and outgoing network traffic of a service in its systemd unit configuration to be able to ensure that some services get a higher priority for ...
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22 views

How do I use TC to prioritise a device on the network?

I'm running a home network using a Linux gateway (raspbian) as a router. It's a simple setup just using iptables as a firewall and traffic forwarding between the local and ppp0 interface. I want to be ...
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1answer
42 views

Why does iperf results not change with traffic control change to outbound?

I have been trying to change bandwidth between two ec2 instances using tc and outbound rules using HTB and TBF. I set these rules on on ec2 instance which acts as server and then test from another ...
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1answer
25 views

Is there a back-pressure mechanism from qdisc to TCP?

Is there a mechanism to stop TCP sending packets towards Qdisc if the queue length exceeds the limit? I know TSQ helps here for a small number of connections but what if I have 1000 connections or ...
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What is the equivalent tool TC (Traffic Control) for Solaris?

I would like to know if anyone knows a way to emulate what TC does on Linux. I have some scripts that I would like to port to Solaris.
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245 views

Problem of limit bandwidth on a specific port in Ubuntu18.04

I set up a socks proxy server listening on 2 ports, 10001-10002. The port 10001 is provided to anonymous user. So, I want to limit the max bandwidth to 1 MB/s, and limit the max bandwidth of port ...
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92 views

Netem does not show the correct parameter inserted

I'm issuing the following tc command tc qdisc in order to configure different queues in a computer. The problem is that when I configure two different queues (htb configuration) and I insert ...
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152 views

egress traffic shaping rules on mirrored interface aren't working

In my small, private, network I have a device (IP address 192.168.0.240) which I want to have a "guaranteed" section of the pipe. To that end, I've been following this Server Fault article to shape ...
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1answer
325 views

qdisc resets after changing to htb

Background I have a system running Ubuntu which has two interfaces eno1 and enp4s0. I have created an OVS bridge using: ovs-vsctl add br s1 I added the two physical interfaces eno1 and enp4s0 to ...
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1answer
763 views

Example command to set same DSCP value in the IP header for return packets within the same TCP connection

I have seen connmark or ctinfo could work for this but couldn't find a simple effective command to make it work (Not familiar within this area). The command can be applied to the TCP termination node ...
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1k views

Adding qdisc under the mq top-level qdisc

This LWN article suggests that one may add/replace the network scheduler for a queue "under" the mq "dummy scheduler." These two point to that end: The mq scheduler does two things: - present ...
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2answers
602 views

Mirror to Multiple Ports Using TC?

Does anyone know if it's possible to mirror to multiple interfaces from one source interface using TC? I've done the following: The first thing I did was create an ingress queue on my input interface ...
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1answer
524 views

tc qdisc not delete filter

I have a problem with understand tc behaviour, especially how is working qdisc deletion. My main problem is why tc qdisc did not delete the attached filter? I did: tc qdisc add dev eth ingress tc ...
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735 views

Traffic control (TC) command with u32 filter - Not working (RTNETLINK answers: Invalid argument)

I am working on college assignment, in which our teacher asked us to block some BPDU packets (which are generated by interface, incoming packets are blocked by BPDU guard) using traffic control tc's ...
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1answer
174 views

Difference between MTU and Burst at Linux-TC

I did a small experiment by using Linux-tc My question is what is the difference between Burst and MTU at Linux tc-htb It seems that they have a same effect. They change a only burst value. (we can ...
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1answer
593 views

How many qdiscs can I create with tc?

I am trying to emulate traffic among multiple virtual machines. Each connection is supposed to have different parameters, i.e. delay. Therefore, I am trying to create different qdisc filters for ...
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68 views

tc: route all traffic from default gateway to ifb0

Traffic from eth0 arriving from gateway should be sent to ifb0 for ingress shaphing. Here some relevant outputs and commands ip route default via 192.168.0.1 dev eth0 metric 200 realm 1 What ...
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195 views

Using tc rate limit all traffic except from one IP

Currently i have the below rule for rate limiting the traffic on port 22. This applies for all traffic, however i don't want this to apply for one IP say x.x.x.x , how to do this? So if the traffic is ...
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896 views

Tc qdisc delay not seen in tcpdump recording

I have two linux containers connected with a veth-pair. At veth-interface of one container I set up tc qdisc netem delay and send traffic from it to the other container. If I watch traffic on both ...
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370 views

Simulate network on a single machine

I'm trying to simulate a network on a single machine. I have multiple nodes that communicate through tcp sockets. I tried to create one dummy interface for each node like this: ip link add name ...
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1answer
1k views

For veth pair, ping does not recognize interface name and tc qdisc netem does not work

I have Ubuntu 16.04 LTS with hwe kernel 4.13.0-39-generic. I configure the veth pair in the default network namespace as follows: $ sudo ip link add h1-eth0 type veth peer name h2-eth0 $ sudo ip ...
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47 views

Are there any disadvantages of using very low “rate” value for Linux HTB queuing discipline?

I have a use-case where egress traffic on 10Mbps connection needs to be divided into two classes. First class is high-priority traffic which needs to be able to use bandwidth up to 10Mbps. Second ...
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3answers
1k views

queueing in linux-htb

I am trying to understand the queuing mechanism of linux-htb QDisc and QDisc of linux tc in general. What I could gather: During TX, the packet is queued into the queue inside the linux tc. This ...
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879 views

Multiqueue tun/tap interface

I am trying to understand how Multiqueue tuntap interface works. Following the instructions provided at: https://www.kernel.org/doc/Documentation/networking/tuntap.txt I was able to create multiple ...
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257 views

Using netem on traffic filtered by iptables

I would like to use netem for only partion of the traffic on bridge. Edit 1 So, I was able to figure out at least something. tc qdisc del dev eth0.1 root tc qdisc add dev eth0.1 root handle 1: ...
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2answers
1k views

Slowing down a server with traffic shaping

I would like to study the behaviour of an application streaming from a slow server. I'm trying to take advantage of tc-netem to introduce a network delay. Before setting up a more complicated ...
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1answer
184 views

How does one use tc to add latency to a ratelimit?

I read that there's another tool for netfilter that allows you to add latency to a ratelimit. Does anyone have an example of this?
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898 views

Rate limiting with tc on vlans

I have found this prior answer (https://serverfault.com/questions/461153/vlan-based-rate-limiting-using-tc), however attempting to add the vlan match to my script yields : What is "handle"? Usage: ....
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1answer
624 views

How can I use `tc` with diffrent parameters on few virtual interfaces?

I need to simulate network environment with bad network connections for about 1000 hosts. Can tc (with netem) be used with virtual network interfaces (like eth0:0, eth0:1)? When I try to use tc on ...
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148 views

Any interface to access linux's tc flower from another kernel module?

I was looking at linux tc flower source code. I see that when a flow is modified, a netlink message is sent from user space to kernel space to create/delete/modify the flow. Rather than the userspace ...
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566 views

When mirroring ingress traffic on an interface with tc, are only the packets destined for the interface mirrored?

I have a Linux box with 3 physical interfaces, one for management (has an IP address) and two for receiving mirrored traffic from two separate switches that make up a link aggregation group (LAG). The ...
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24 views

IPTABLES: issue with impacting traffic to a subnet using --destination flag

I am applying iptables rule to impact outbound traffic into a subnet. I send the traffic into a new chain created and then tc impose some delay using netem. TC is then using that rules. Something like ...
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393 views

htb -> netem -> pfifo_fast qdisc drops all packets under high traffic

I configured a OpenVSwitch-based topology using Mininet on my local machine: h1 (server) -------(eth1) s1 (eth2)--------------- h2 (client) (eth3) | ...
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1answer
1k views

How can I permanently associate tc qdisc commands with a particular interface?

I need to use a tc qdisc command to limit bandwidth usage on an interface created by openvpn. This works great when I run the command manually but occasionally the connection drops or restarts and ...
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1answer
516 views

Using IFB for ingress traffic shaping

I am trying to use the IFB driver for ingress traffic and are having some problems getting it to work for us. It hooks the packets before netfilter and so marks set with iptables are not seen by tc ...
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0answers
1k views

Performance bottlenecks of Linux traffic shaping (tc)

I have an interesting problem. We have a Linux server with Debian Stretch installed. The server has a single CPU E5-2680 v2 and Intel 82599ES 10G Dual Port NIC's. There are no other services (like ...
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272 views

TC (Traffic control) and trickle: apply different bandwidth to (multiple requests) same IP or URL during upload and download

I have some files of different sizes which I needed to send to Azure blob storage and I am using Azure IOT SDKs to achieve that.Now I have different types of file size ( from 50 MB to 5 GB) and have ...
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80 views

fq_codel - does ath9k_htc support it

I cannot seem to find documentation that says ath9k_htc supports fq_codel, so, it'd be safe to assume that it does not? If I use fq_codel as the queue discipline and ath9k_htc doesn't support it, ...