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shaping-rate

Syntax

Hierarchy Level

Note:

Only switches that support enhanced transmission selection (ETS) hierarchical scheduling support the traffic-control-profiles hierarchy.

Description

Configure the shaping rate. The shaping rate throttles the rate of packet transmission by setting a maximum bandwidth (rate in bits per second) or a maximum percentage of bandwidth for a queue or a forwarding class set. You specify the maximum bandwidth for a queue by using a scheduler map to associate a forwarding class (queue) with a scheduler that has a configured shaping rate.

For ETS configuration, you specify the maximum bandwidth for a forwarding class set by setting the shaping rate for a traffic control profile, then you associate the scheduler map with the traffic control profile, and then you apply the traffic control profile and a forwarding class set to an interface.

For simple port scheduling configuration, you apply the scheduler map directly to an interface (instead of indirectly through the traffic control profile as in ETS).

We recommend that you configure the shaping rate as an absolute maximum usage and not as additional usage beyond the configured transmit rate (the minimum guaranteed bandwidth for a queue) or the configured guaranteed rate (the minimum guaranteed bandwidth for a forwarding class set).

Note:

When you set the maximum bandwidth (shaping-rate value) for a queue or for a priority group at 100 Kbps or less, the traffic shaping behavior is accurate only within +/– 20 percent of the configured shaping-rate value.

Note:

On QFX5200, QFX5100, EX4600, QFX3500, and QFX3600 switches, and on QFabric systems, we recommend that you always apply a shaping rate to strict-high priority queues to prevent them from starving other queues. If you do not apply a shaping rate to limit the amount of bandwidth a strict-high priority queue can use, then the strict-high priority queue can use all of the available port bandwidth and starve other queues on the port.

Note:

On QFX5200 Series switches, a granularity of 64kbps is supported for the shaping rate. Therefore, the shaping rate on queues for 100g interfaces might not be applied correctly.

Note:

QFX10000 Series switches do not support the shaping-rate statement. However, you can configure the transmit-rate exact option to prevent a queue from consuming more bandwidth than you want the queue to consume.

On QFX10000 Series switches, we recommend that you use the transmit rate to set a limit on the amount of bandwidth that receives strict-high priority treatment on a strict-high priority queue. Traffic up to the transmit rate receives strict-high priority treatment. Traffic in excess of the transmit rate is treated as best-effort traffic that receives the strict-high priority queue excess rate weight of “1”. Do not use a shaping rate to set a maximum bandwidth limit on strict-high priority queues on QFX10000 Series switches.

Default

If you do not configure a shaping rate, the default shaping rate is 100 percent (all of the available bandwidth), which is the equivalent of no rate shaping.

Options

percent percentage—Shaping rate as a percentage of the available interface bandwidth.

  • Range: 1 through 100 percent

rate—Peak (maximum) rate, in bits per second (bps). You can specify a value in bits per second either as a complete decimal number or as a decimal number followed by the abbreviation k (1000), m (1,000,000), or g (1,000,000,000).

  • Range: 1000 through 10,000,000,000 bps

Required Privilege Level

interface—To view this statement in the configuration.

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

Release Information

Statement introduced in Junos OS Release 11.1.