The Linux kernel has a flexible set of tools built into a subsystem called the traffic control system. The kernel structures in this subsystem allow many different operations on packets and flows, ranging from shaping, policing, prioritization and dropping of packets to bandwidth sharing and dynamic delay control. Naturally, a rich set of packet classification tools supports these features.
The Traffic Control HOWTO article is also available at TLDP.
The DocBook source XML is also available (clonable as follows):
git clone https://github.com/tLDP/LDP # cd LDP/LDP/howto/docbook/Traffic-Control-HOWTO/
Hierarchical Fair Service Curve is a queuing discipline which allows control over the distribution of latency and bandwidth to classes of flows. Patrick McHardy and Klaus Rechert wrote an article for the German-language Linux Magazin in 2005. Patrick McHardy authored the Linux HFSC qdisc implementing this original idea for link sharing.
This is my English translation of the original German-language HFSC article.
Werner Almesberger wrote a utility called Traffic Control Next Generation, which allowed a more readable way of writing traffic control configurations. This article describes how to use Hierarchical Token Bucket (HTB) with tcng.
The Traffic Control using tcng and HTB HOWTO is also posted at TLDP. The DocBook source is also available (clonable as follows):
git clone https://github.com/tLDP/LDP # ls -l LDP/LDP/howto/docbook/Traffic-Control-tcng-HTB-HOWTO.xml
Unfortunately, it seems that tcng development has been stalled for nearly a decade (2016-04-04).
All of these were last updated from the iproute2 source around 2016-04-13. The software version at that time was version iproute2-4.5.0.
The iproute2 suite is the Linux-specific command-line toolkit for interacting with the kernel data structures which run the networking stack. The toolkit allows address and route enumeration, statistics gathering, traffic control management and, of course, configuration.
IP Command Reference
Another introductory text by somebody trying to dive into the Linux traffic control subsystem, specifically, focusing on the tc filter command.
QoS in Linux with TC and Filters
These are some other little utilities hidden deep in the back of the Linux closet. They are abstruse and might even be defunct.