buffer-size (Schedulers)

Syntax

Hierarchy Level

Description

Specify buffer size in a scheduler configuration.

You configure the proportion of port buffers allocated to a particular output queue using the following process:

1. Configure a scheduler and set the buffer-size option.

2. Use a scheduler map to map the scheduler to the forwarding class that is mapped to the queue to which you want to apply the buffer size.

   For example, suppose that you want to change the dedicated buffer allocation for best effort traffic. Best effort traffic is mapped to the best effort forwarding class, and the best effort forwarding class is mapped to queue 0 (by default). To use default best effort traffic mapping, in the scheduler map configuration, map the scheduler to the best-effort forwarding class.

3. If you are using hierarchical scheduling, associate the scheduler map with the traffic control profile you want to use on the egress ports that carry best effort traffic. If you are using direct port scheduling, skip this step.

4. If you are using hierarchical scheduling, associate the traffic control profile that includes the scheduler map with the desired egress ports. For this example, you associate the traffic control profile with the ports that carry best effort traffic. If you are using port scheduling, associate the scheduler map with the desired egress ports.

   Queue 0, which is mapped to the best effort forwarding class and therefore to best effort traffic, receives the dedicated buffer allocation specified in the buffer-size statement.

Note:

The total of all of the explicitly configured buffer size percentages for all of the queues on a port cannot exceed 100 percent.

Note:

On PTX Series Packet Transport Routers, you cannot configure buffer-size on rate-limited queues.

Default

If you do not include this statement, the default scheduler transmission rate and buffer size percentages for queues 0 through 7 are 95, 0, 0, 5, 0, 0, 0, and 0 percent, respectively.

Options

percent percentage	Buffer size as a percentage of the total buffer. Range: 0 through 100
remainder	Remaining buffer available.
shared	On PTX Series routers, set a queue’s buffer to be up to 100 percent of the interface’s buffer. This option allows the queue’s buffer to grow as large as 100 percent of the interface's buffer if and only if it is the only active queue for the interface.
temporal microseconds	Buffer size as a temporal value. The queuing algorithm starts dropping packets when it queues more than a computed number of bytes. This maximum is computed by multiplying the logical interface speed by the configured temporal value.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced before Junos OS Release 7.4.

shared option introduced in Junos OS Release 18.1.