Linux tc qdisc pie (aqm) configuration with limited bandwidth

htblinuxrate-limitingtctraffic-shaping

I would like to configure AQM PIE by using tc-qdisc, but at the same time I would like to limit the bandwidth to 1Mb/s.

I have used similar configuration with fq_codel, i.e. I have limited the bandwidth by using htb, and later configured fq_codel for the leaf class, as it is done in this example https://www.linux.com/community/blogs/133-general-linux/879656-qos-in-linux-with-tc-and-filters

So for pie I do:

 tc qdisc add dev eth0 handle 1: root htb default 11
 tc class add dev eth0 parent 1: classid 1:1 htb rate 1000kbit ceil 1000kbit
 tc class add dev eth0 parent 1:1 classid 1:11 htb rate 1000kbit ceil
   1000kbit 
 tc qdisc add dev eth0 parent 1:11 pie

However I get "qdisc uknown" message and for example when I try to change any arguments of pie, I get an error: Unknown qdisc "pie", hence option "alpha" is unparsable.

Is it possible to use pie and limit the bandwidth at the same time?

Thank you in advance for any help.

Best Answer

PIE was added to the Linux kernel in version 3.14 (https://www.linux.com/news/linux-314-release-no-pi-new-pie-fights-bufferbloat), so you need a Linux version >= 3.14 in order to run PIE. In order to configure PIE, you also need an up-to-date version of the tc utility, which is part of iproute2. You can download the appropriate version of iproute2 for your Linux kernel here.

Related Solutions

Linux – Minimal rate and default class problem for HTB

Since you didn't include the classifiers it's hard to deduct what traffic you exactly mean in each class. For instance, outgoing http or ssh traffic is very important for interactivity, incoming http not so much.

I would guarantee certain bandwidth for each service by saying: I have x kbps for incoming httpd traffic, and it gets divided equally among the users. If you have 10 or 100 users, it's fair." If you have high priority users or low priority users in each of these services you need to have additional classes and classifiers for them.

(Also I hope you know you can only shape outgoing traffic from an interface, NOT the incoming. That means if you want to limit the uplink, you have to work either with the outgoing interface to the internet or use the Intermediate Queuing Device. The lartc.org Guide is a very good resource.)

Iptables – How to add delay to incoming traffic

Adding delay can be done on incoming (ingress) or outgoing (egress) packets (or both). Delaying ingress packets is a bit harder (cause the packet has already arrived) but is achievable with Intermediate Functional Block device (have a look here. search for "netem on incoming traffic").

Because your goal can be achieved by delaying ingress or egress traffic and delaying egress is easier, I'd recommend to do that. Your configuration is almost correct: you just need to replace the iptables mangle line with

sudo iptables -t mangle -A OUTPUT -p tcp -m tcp --sport 80 -j MARK --set-mark 11

Best Answer

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Linux – Minimal rate and default class problem for HTB

Iptables – How to add delay to incoming traffic

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