Setting the Committed Burst for a Rate-Limit Profile

You can use the committed-burst command to set the committed burst in bytes; range is 1–4294967295. You can use the committed-burst command to set the committed burst in milliseconds for a rate-limit profile; range is 1–10000. The no version restores the default value, 8192 bytes if the rate is in bytes per second; 100 milliseconds if the rate is in milliseconds.

When you specify a nonzero value for the rate, the burst size is automatically calculated for a 100-ms burst as described for the committed-rate command. If the calculated burst size is less than the default value of 8 KB, the default value (8192 bytes) is used.

Note: We recommend that you do not configure a committed or peak burst size smaller than the MTU of the interface. Doing so causes large packets to be dropped even when they are transmitted at a very low rate.

When you specify a nonzero value for the committed rate, the committed burst size is calculated based on a 100-ms burst as follows:

committed burst in bytes = (committed rate in bps x 100 ms) ÷ 8 bits per byte

The router displays committed rate in bits per second and committed burst in bytes. For example, if the rate is 8 Mbps, the burst size is 100 ms x 8 Mbps = 800,000 bits or 100,000 bytes:

committed burst = (8,000,000 bps x 100 ms) ÷ 8 = 100,000 bytes

For this example, displaying the rate-limit profile shows:

committed-rate 8000000

committed-burst 100000

If the calculated burst value is less than the default burst size of 8 KB, the default burst size is used. For most configurations this value probably is sufficient, making it optional for you to configure a value for the associated committed burst size.

To configure the committed burst, enter Rate Limit Profile Configuration mode.

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