queue-depth (WRED drop profile view)

Function

The queue-depth command sets the length of a queue.

The undo queue-depth command restores the default length of a queue.

By default, the system uniformly manages the lengths of queues.

Format

queue-depth queue-depth-value

undo queue-depth

Only the S5720-HI, S5731-S, S5731S-S, S5731-H, and S5731S-H support this command.

Parameters

Parameter	Description	Value
queue-depth-value	Specifies the queue length.	The value is an integer that ranges from 1024 to 805306368, in bytes.

Views

Drop profile view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

When packets entering interface queues are processed based on parameters in a WRED drop profile, the percentage of the packet length to the queue length needs to be calculated. When the percentage reaches the lower drop threshold, the switch discards packets based on the drop probability. When the percentage reaches the upper drop threshold, the switch discards all subsequent packets. You can adjust the queue length to optimize the congestion avoidance effect.

Prerequisites

A WRED drop profile has been created and the WRED drop profile view has been displayed.

Precautions

When a small queue length is used, the delay of packets passing a queue is shortened but the queue buffer capability is lowered. When a large queue length is used, the queue buffer capability is improved but the delay of packets passing a queue is extended. In addition, when congestion occurs in a queue, many buffer resources are occupied. In this case, packets in other queues may be discarded due to insufficient buffer resources.

Example

# Configure WRED drop profile wred1 and set the queue length to 2000 bytes.

<HUAWEI> system-view
[HUAWEI] drop-profile wred1
[HUAWEI-drop-wred1] queue-depth 2000