Applying the QoS policy to a control plane
A device provides the data plane and the control plane.
Data plane—The units at the data plane are responsible for receiving, transmitting, and switching (forwarding) packets, such as various dedicated forwarding chips. They deliver super processing speeds and throughput.
Control plane—The units at the control plane are processing units running most routing and switching protocols. They are responsible for protocol packet resolution and calculation, such as CPUs. Compared with data plane units, the control plane units allow for great packet processing flexibility but have lower throughput.
When the data plane receives packets that it cannot recognize or process, it transmits them to the control plane. If the transmission rate exceeds the processing capability of the control plane, the control plane will be busy handling undesired packets. As a result, the control plane will fail to handle legitimate packets correctly or timely. As a result, protocol performance is affected.
To address this problem, apply a QoS policy to the control plane to take QoS actions, such as traffic filtering or rate limiting, on inbound traffic. This ensures that the control plane can correctly receive, transmit, and process packets.
A predefined control plane QoS policy uses the protocol type or protocol group type to identify the type of packets sent to the control plane. You can use protocol types or protocol group types in if-match commands in traffic class view for traffic classification. Then you can reconfigure traffic behaviors for these traffic classes as required. You can use the display qos policy control-plane pre-defined command to display predefined control plane QoS policies.
Configuration restrictions and guidelines
When you apply a QoS policy to a control plane, follow these restrictions and guidelines:
If the hardware resources of an IRF member device are insufficient, applying a QoS policy globally might fail on the IRF member device. The system does not automatically roll back the QoS policy configuration already applied to other IRF member devices. To ensure consistency, use the undo qos apply policy command to manually remove the QoS policy configuration applied to them.
If a class uses control plane protocols or control plane protocol groups as match criteria, the action in the associated traffic behavior can only be car or the combination of car and accounting packet. Only the cir keyword in the car action can be applied correctly.
Configuration procedure
To apply the QoS policy to a control plane:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter control plane view. | control-plane slot slot-number | N/A |
3. Apply the QoS policy to the control plane. | qos apply policy policy-name inbound | By default, no QoS policy is applied to a control plane. |