Flexible Hierarchical Shaping
(Back-haul Congestion Mitigation)

Operators map their network hierarchy in LibreQoS. This enables both simple network hierarchies (Site>AP>Client) as well as much more complex ones (Site>Site>Micro-PoP>AP>Site>AP>Client). This can be used to ensure that a given site’s peak bandwidth will not exceed the capacity of its back-haul links (back-haul congestion control). Operators can support more users on the same network equipment with LibreQoS than with competing QoE solutions which only shape by AP and Client.


LibreQoS offers multi-CPU IP filtering via two XDP programs – xdp-cpumap-tc and cpumap-pping. XDP (the eXpress Data Path) allows for high-performance packet processing that can integrate cooperatively with the Linux kernel.


CAKE is the product of nearly a decade of development efforts to improve on fq_codel. With the diffserv4 parameter enabled – CAKE groups traffic in to Bulk, Best Effort, Video, and Voice. This means that without having to fine-tune traffic priorities – CAKE automatically ensures your clients’ OS update downloads will not disrupt their zoom calls. It allows for multiple video conferences to operate on the same connection which might otherwise “fight” for upload bandwidth causing call disruptions. With work-from-home, remote learning, and tele-medicine becoming increasingly common – minimizing video call disruptions can save jobs, keep students engaged, and help ensure equitable access to medical care.


Graph metrics including:

  • Bandwidth Utilization
  • Circuit / Node Utilization
  • CAKE DiffServ Tin Selection
  • TCP Round Trip Time Latency

IPv4 & IPv6

Support for assigning IPv4 addresses and subnets, as well as IPv6 prefixes of arbitrary length.


  • UISP
    • Full Topology Mapping (Site, AP, Micro-PoP, etc)
    • Client Mapping
  • Splynx
    • Client Mapping

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Net Neutrality

ISPs located in the European Union, and many located in the United States – are subject to laws regarding Net Neutrality. Net Neutrality is “the principle that ISPs should treat all Internet communications equally, offering users and online content providers consistent rates irrespective of content, website, platform, application, type of equipment, source address, destination address, or method of communication”.[1]
We believe that LibreQoS is the most net neutral QoE platform available, because it focuses on providing an equitable, fair experience for all users on the network. LibreQoS uses CAKE per-end-user, rather than just broadly shaping flows of traffic by category, which is less effective in delivering a quality user experience.
Some other QoE solutions use Deep Packet Inspection (DPI) to categorize and de-prioritize or limit certain classes of traffic. These products advertise their ability to constrict streaming video traffic to force an end-users video to downscale from 4K to HD, or to identify speed test traffic and increase a subscriber’s allotted bandwidth only during that speed test. Such approaches are legally risky for ISPs located in territories where Net Neutrality is legally enforced. In the US for example – regulations such as California’s SB-822 clarify that “Reasonable Network Management” needs to be “as application-agnostic as possible”. In the past, companies have paid up to $16 million in settlements over using DPI in this way.
Instead, LibreQoS focuses on delivering Quality of Experience through Flow Queuing with CAKE.
"FQ is an attempt at Net Neutrality in the sense that it tries to treat users fairly and resist hogging effects. It's sophisticated Net Neutrality."
Vint Cerf
Co-designer of the TCP/IP protocols and architecture of the Internet
For US operators, below is a table listing some states which have passed Net Neutrality regulation, along with links to the full text of their regulation. This table is not comprehensive.
OregonH.B. 4155RegulationState Contracts
VermontS.B. 289RegulationState Contracts
WashingtonH.B. 2282RegulationAll ISPs
CaliforniaSB-822RegulationAll ISPs
HawaiiExecutive Order 18-02Executive OrderState Contracts
MontanaExecutive Order 3-2018Executive OrderState Contracts
New JerseyExecutive Order 9Executive OrderAll ISPs
New YorkExecutive Order 175Executive OrderState Contracts
Rhode IslandExecutive Order 18-02Executive OrderState Contracts
ColoradoSB19-078RegulationState Contracts
MaineLD 1364RegulationState Contracts

Libre Software

LibreQoS is Free and Open Source software (Libre software) licensed under the GPLv2.

Open source projects have the advantage that many developers are able to see the code – then catch and correct bugs that would otherwise be overlooked in closed-source development projects.

Most closed-source QoE platforms are built on open source foundations – fq_codel, CAKE, HTB, XDP, DPDK, and eBPF. Closed-source QoE developers have to develop their platforms completely disconnected from the community of developers which created the underlying framework of their platforms. There is important information lost there, and the absence of information exchange means that implementation errors go undetected.

LibreQoS has benefited from feedback by the original authors of fq_codel, CAKE, and XDP – allowing us to catch and correct implementation errors promptly. If a closed-source QoE solution has implementation mistakes or missed opportunities for optimization – who will catch that? An open source project saves everyone time and effort in this regard.

Upstream Contributions

Unlike most commercial QoE solutions, the LibreQoS project collaborates with the open source projects which make it possible (Linux, XDP, CAKE, eBPF, Rust). When you participate in the LibreQoS project, you are strengthening the long term development of its upstream projects, particularly XDP and CAKE – which will shape the future of the internet, and hopefully create a better internet for billions of users around the world.