H3C Technologies H3C SR8800 - Manual (Page 80)

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Configuring HQoS
HQoS overview
Introduction to HQoS
Quality of Service (QoS) is widely used in networks to ensure transmission quality and provide
differentiated service levels for various data flows.
In response to increased network users and service types, Ethernet devices are required not only to further
subdivide service traffic but also to uniformly manage and hierarchically schedule traffic by user in
addition to service. This is beyond the capability of traditional QoS.
Hierarchical Quality of Service (QoS) uniformly manages traffic and hierarchically schedules traffic by
user, network service, and application. It provides more granular traffic control and quality assurance
services than traditional QoS.
HQoS-capable devices can hierarchically classify and schedule traffic, for example, by both user and
application, and control internal resources based on policies at different levels. HQoS guarantees QoS
for advanced users and saves the overall networking costs.
How HQoS works
To achieve hierarchical scheduling, Hierarchical Quality of Service (HQoS) was developed. It organizes
a scheduler policy into a hierarchical tree that consists of a root node, branches nodes, and leaf nodes,
where:
• The root node is the convergence point for all traffic and corresponds to a scheduler.
• A branch node is located in the middle of the hierarchy and corresponds to a scheduler.
• A leaf node is at the bottom layer and corresponds to a scheduling queue.
A scheduler can schedule multiple scheduling queues or schedulers. Each node is configured with match
criteria and control parameters. The match criteria determine the traffic direction and the control
parameters define control actions for traffic traversing this node.
Parent nodes and nested child nodes also exist in the hierarchical tree. A parent node is the convergence
point for the traffic of its child nodes. Traffic that has been classified and regulated at a child node will
be re-classified and regulated together with other traffic streams at the parent node. By configuring
match criteria and actions oriented to different levels (user-level, service level, and traffic type level, for
example) on the child and parent nodes, you can achieve hierarchical traffic management.
Figure 25 shows how HQoS works. The QoS-local-ID range next to a node is the match criteria of the
node. Strict priority, weighted round robin (WRR), or generic traffic shaping (GTS) in the arrow pointing
to an upstream node is the control parameter of the current node. With the topmost scheduler policy
applied to an interface, you can classify and manage the inbound traffic of the interface multiple times.