R3303-HP HSR6800 Routers ACL and QoS Configuration Guide

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traffic rate is higher than the CIR, the system colors the packets red and performs the action for red
packets (including marking priority, forwarding, proceeding with the next CAR action, and dropping).
CAR is widely used in networks because it is easy to configure and provides obvious rate-limiting effects.
However, traditional CAR provides a fixed upper rate limit, and cannot enable bandwidth sharing and
prioritize the specific traffic. The routers supports interface-level hierarchical CAR, which can meet the
requirements mentioned above.
To use the interface-level hierarchical CAR to implement HQoS, configure multiple CAR policies of
different levels in the inbound or outbound direction of an interface.
In the level-1 CAR policy, color the packets to be prioritized and within the guaranteed bandwidth green
to improve the packet priority, and color the packets exceeding the guaranteed bandwidth red. The
action for green and red packets is using the next CAR policy, so the red packets continue to be
processed by using the level-2 CAR policy.
In the level-2 CAR policy, red packets are forwarded until all green packets are forwarded. In this way,
the specific packets are prioritized. Additionally, compared with the level-1 CAR policy, the level-2 CAR
policy sets higher bandwidth for low-priority traffic to implement bandwidth sharing.
HQoS implemented by using interface-level hierarchical CAR is easy to configure, and can cooperate
with CAR actions and policy-based routing to implement different QoS functions. At the same time,
HQoS implemented by using interface-level hierarchical CAR can better utilize the bandwidth than
HQoS implemented through nesting QoS policies.
Packets that have not been processed by CAR are green by default. Packets colored red by CAR cannot
be colored green.