qos queue buffer shared-ratio
Function
The qos queue buffer shared-ratio command sets the maximum ratio of the dynamic buffer occupied by a queue on an interface.
The undo qos queue buffer shared-ratio command restores the default maximum ratio of the dynamic buffer occupied by a queue on an interface.
By default, the maximum ratio of the dynamic buffer occupied by a queue on an interface of the S5720-EI is 50%, and the maximum ratio of the dynamic buffer occupied by a queue on an interface of the S6720-EI and S6720S-EI is 20%.
Only the S5720-EI, S6720-EI, and S6720S-EI support this command.
Format
qos queue queue-index buffer shared-ratio ratio-value
undo qos queue queue-index buffer shared-ratio
Parameters
Parameter |
Description |
Value |
|---|---|---|
queue-index |
Specifies the index of a queue. |
The value is an integer that ranges from 0 to 7. |
ratio-value |
Specifies the maximum ratio of the dynamic buffer occupied by a queue on an interface, in percentage. |
The value is an integer that ranges from 1 to 90.
|
Usage Guidelines
Usage Scenario
By default, the buffer of an interface is small. When the traffic rate on an interface reaches 50% to 60% of the interface bandwidth, packets are lost on the interface. The switch uses static and dynamic modes to allocate the buffer. The switch allocates specified static buffer to each interface, and the remaining buffer is used as the dynamic buffer. When there is heavy burst traffic in a queue on an interface, you can run the qos queue buffer shared-ratio command to increase the maximum ratio of the dynamic buffer occupied by the queue. The switch allocates larger dynamic buffer to the queue to reduce packet loss on the queue.
Precautions
The available dynamic buffer on each interface is limited. When a queue on an interface occupies more dynamic buffer, there is less dynamic buffer that can be occupied by other queues on the interface. As a result, the queues' capability to forward burst traffic is lowered.
The qos queue buffer shared-ratio and qos burst-mode (system view) commands cannot be configured on the switch simultaneously.
The qos queue buffer shared-ratio and qos burst-mode (interface view) commands cannot be configured on the same interface simultaneously.