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Questions tagged [tc]

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

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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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0answers
12 views

Is there a way to find NetEm delay selected when using distribution table?

I am trying to find how much each packets are delayed when it is passed through NetEm from one PC to another via an ethernet cable. At the moment I am using Wireshark to find delay experienced by each ...
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0answers
14 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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43 views

How to properly configure tc-fq and other qdiscs, bits change to bytes

When enabling a fair queue with sudo tc qdisc replace dev eth1 root fq maxrate 400kbps and then showing the qdisc with tc -g qdisc show dev eth1 yields qdisc fq 8001: root refcnt 2 limit 10000p ...
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3answers
101 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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41 views

Control Internet Bandwidth with tc on Raspberry Pi 3?

Modem/Router is connected to Internet (192.168.1.1) No DHCP server is running on Modem/Router Devices connect to the network through Wifi provided by Modem/Router Devices receive DHCP settings ...
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0answers
99 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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40 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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31 views

tc-netem ignores set rate limit and packet reordering

I want to rate-limit an ethernet-interface via netem using tc. According to the man-page (and examples found here and via google) it can be done like tc qdisc add dev enp0s25 root netem rate 512kbit (...
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10 views

limit on the Number of QoS Queues

Please let me know is there a limit on the number of QoS queues that can be created for one network Interface?
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2answers
125 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
26 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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1answer
147 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
53 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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0answers
92 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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0answers
214 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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0answers
12 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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114 views

Prioritize outgoing network traffic across multiple interfaces

Background My Ubuntu server is configured with a VPN Split Tunnel (all traffic from one user is sent through a VPN, while the rest of my traffic is sent normally). Therefore, I have two main network ...
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0answers
192 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
405 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 ...
2
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1answer
277 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
721 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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0answers
176 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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102 views

HTB traffic shaper - download speed degrade

I have Oracle Linux Server with latest kernel-3.8.13.... On server goes traffic shaping and some iptables rules. Server have three Intel i350-T2 dual Gigabit network adapters. Cooperated by 3 ...
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59 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, ...
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153 views

shorewall - problems with traffic shaping

I'm shaping my traffic such that VoIP calls have highest priority, followed by, VPN, then general network surfing, and lastly, large downloads. [tcclasses] lw 1 200kbit full 1 tos=0x68/0xfc,tos=0xb8/...
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1answer
114 views

wireshark packet capture point [closed]

I am using tc qdisc to add delay to packets on my interface eth2 as follows sudo tc qdisc add dev eth2 root netem delay 100ms 10ms 25% Then I pinged a host and got some result. The results on the ...
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0answers
350 views

Delay some localhost traffic

How to delay some localhost traffic? (the computer is a VM, but hopefully that won't matter) The following creates a new interface and tries to apply tc to it: ifconfig lo:1 127.0.10.10 netmask 255....
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0answers
69 views

Exclude a specific network from the tc rules

Even though there are numerous resources on how to create and manipulate traffic control settings using the tc command on Linux, I can't find anything useful around network exclusion in tc. I would ...
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0answers
1k views

How to limit download bandwidth per IP?

We are running Ookla Speedtest server and want to limit download bandwidth per IP (350Mbit/s per IP). And I cannot find some examples how to do that. All the examples with tc are about how to limit ...
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0answers
151 views

How to set an general network limit per client + priority for TCP acknowledgements

Following situation: Network A is connected to network B over an slow connection. Different hosts in network A would like to send traffic to hosts in network B. Hosts in network B sending commands to ...
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1answer
73 views

Why I don't see drops with TCP flows in linux

I wanted to observe the congestion window of a TCP flow so for that I have two nodes (using linux namespaces) connected to each other through veth pairs and a bridge. To limit bandwitdh to 10mbps I ...
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1answer
846 views

iptables: download quota per mac address for all hosts

On a Linux router, how to setup download quotas for all hosts? This is for a shared wifi network with many guests: Each guest should start with a 150 Mb download quota and no restriction Once quota ...
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0answers
64 views

tc command linux [closed]

I was trying to achieve bandwidth limit in linux boxes. I was able to filter traffic using IP addresses. But I have MPLS running in the network. Is it possible to limit is using it LDP labels ? Does ...
2
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1answer
783 views

How do packets traverse tc/netfilter physical, VLAN and bridge interfaces?

Given the following setup on a router that performs NAT between two networks A and B: eth0 - physical interface - no ip address eth0.1 - VLAN interface for network A - no ip address eth0.2 - VLAN ...
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0answers
413 views

Remote (REST) API for system administration

I've spent a few hours looking for a FOSS or commercial product to solve my problem, with no success. In the context of a big C++ code-base I was assigned the task to provide some automatic ...
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1answer
1k views

Is TCP PACING enabled by default on linux?

I want to ask a basic question: Is TCP PACING enabled by default on Linux? I'm using Ubuntu right now, kernel 4.4.0. I saw that it can be enabled/disabled using TC-FQ, but is it enabled by default ...
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1answer
480 views

Using tc, I want TCP and UDP to use the same buffer

I have 2 types of traffic TCP UDP I want to apply 2 different filters on them, 1 Mbps b/w for UDP and 7 Mbps b/w for TCP But I want their traffic to use a common buffer of size 100 packets I've ...
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2answers
1k views

Limit bandwidth of individual HTTP requests while not throttling total bandwidth

Looking at tools like tc, wondershaper, htb and comcast, all these tools seem to operate on the level of a network interface or at least a "connection group" for limiting bandwidth. I'd like to not ...
2
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1answer
971 views

Why does this tc ingress limit command not work? (bandwidth drops off to nothing)

I'm trying to police my downstream bandwith for a given port - but it seems unless I have a gigantic limit and burst, the download stops completely IF="wlp3s0" LIMIT="100kbit" BURST="100kbit" PORT="...
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1answer
2k views

How can I limit Download bandwidth of an existing process? (iptables, tc, ?)

I am happily limiting upload speed by port - but really want to limit download by process. It seems iptables did have functionality for matching and marking packets by process in the form of --pid-...
2
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1answer
749 views

Alternative to Iptables for packet filtering in OVS interfaces

I just realised that all the iptables rules I have been applying to my open Vswitch interfaces never match. I am using iptables to mark some packets, and then I use TC (traffic control) filters to ...
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0answers
91 views

How to block Traffic Control (tc) operation if started as non-root?

I disallowed users to launch tc binary from standard location but if they download it from network to home directory they can view traffic control settings. How can I disallow interaction between tc (...
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0answers
166 views

Giving maximum priority to some traffic

I have all my interfaces configured as follows: tc qdisc add dev eth0 root handle 1: htb default 20 tc class add dev eth0 parent 1: classid 1:1 htb rate 10.0Mbit burst 15k tc class add dev eth0 ...
3
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1answer
363 views

TCP flows coexisting with UDP when using SFQ (stochastic fair queuing)

I am simulating a network where I limited and modified all the interfaces using TC (traffic control). My interfaces are of the form HTB --- SFQ (it is a little bit more complex but I will simplify ...
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0answers
169 views

Load sharing across multiple interfaces using tc

I created a simple topology in GENI (http://www.geni.net/) and it looks like the following: A --- Router_1 === Router_2 --- B (Note that there are two links between routers 1 and 2.) I am trying to ...
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0answers
156 views

I want to limit a SFQ qdisc by bytes [closed]

I have to HTB branches that continue to a SFQ qdisc. tc qdisc add dev eth0 root handle 1: htb default 20 tc class add dev eth0 parent 1: classid 1:1 htb tc class add dev eth0 parent 1:1 classid 1:10 ...
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0answers
74 views

Shape traffic flowing through dd-wrt router

I am working on an experiment in which several devices connect to each other via a wireless network. I want to be able to shape the traffic between the devices, i.e., control the bandwidth, latency, ...
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1answer
798 views

Using qdisc prio under htb class

I have 2 services, both operate over the same interface. Service A goal is keep high bandwidth while sending massive amount of data. Service B goal is low latency. Service B packets should always ...
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0answers
833 views

How is the IMQ device positioned in the packet flow of the Linux kernel

I would like to know the exact position of the following device in the packet flow for ingress traffic shaping: IFB: Intermediate Functional Block I would like to better understand how packets are ...