What is HQoS
HQoS (Hierarchical Quality of Service) is an advanced traffic management mechanism. By combining multi-level queue scheduling and traffic shaping, it provides granular bandwidth control and priority assurance for complex network traffic. The result is higher bandwidth utilization and reliable service quality for critical applications such as voice and video.
Traditional QoS typically manages traffic at a single node or interface, applying one set of rules to a port or a queue. That works for simple scenarios, but falls short when bandwidth must be divided among many tenants, departments, or subscribers, each running several services with different priorities. HQoS solves this by introducing hierarchy: traffic is managed in nested levels at the same time, such as the overall link, user groups, individual users, and the different service types within each user. Each level has its own rate limit, and every level is enforced together, so a single physical link can be shared fairly without letting any one group or service starve the others.
How HQoS Works
HQoS organizes traffic control into a tree of levels. Each level can enforce its own rate limit, and traffic must satisfy every level above it before it is forwarded.
· Global level: The top of the hierarchy. A global HQoS profile defines the overall rate limit for the link and serves as the container for all user groups and users beneath it.
· User group level: A user group aggregates multiple users, such as a department, a tenant, or a customer tier, and can be given its own shaping rate. Users that do not belong to any custom group fall into a default user group, which can be rate limited as well.
· User level: Each user can have an individual rate limit. Users that are not explicitly defined fall into a default user profile.
· Service (queue) level: Within each user, traffic is divided into traffic class (TC) queues. Each queue can be scheduled in strict priority or DWRR (Deficit Weighted Round Robin) mode and shaped to its own rate, so latency-sensitive traffic such as voice or video conferencing is served first and still bounded.
The operating process is as follows:
Traffic is classified and assigned to a user, for example by matching source addresses with an ACL.
A DSCP-to-TC priority mapping places each service into the appropriate traffic class queue.
Each queue is scheduled (strict priority or DWRR) and shaped to its configured peak information rate (PIR) and peak burst size (PBS).
User traffic is then aggregated and shaped at the user group level, and finally limited by the global rate.
The HQoS profile is bound to an interface. By default each interface operates independently; in shared mode, all interfaces bound to the same profile share the single rate limit defined in it.
Users and user groups can be bound in bulk using prefix, suffix, or fuzzy name matching, which keeps large deployments manageable.
Why HQoS is Beneficial
The core value of HQoS lies in precise, multi-dimensional control over shared bandwidth:
· Granular bandwidth control: Limits can be set at the link, group, user, and service level at once, instead of a single rate on a port.
· Guaranteed service quality: Critical applications such as voice and video get priority scheduling and a defined bandwidth allocation, even when the link is congested.
· Fair sharing between tenants: Departments, customers, or subscribers each receive their allocated share, and one group's traffic burst cannot consume the bandwidth of another.
· Better bandwidth utilization: Hierarchical shaping and scheduling make full use of the available link capacity while still honoring each level's limits.
· Scalable operation: Bulk matching and default profiles let administrators apply consistent policies to many users without configuring each one by hand.