Parameters and examples of throttling functions - CDN - Alibaba Cloud Documentation Center

Use limit_rate_after and limit_rate together to control the data transfer rate for individual CDN requests. Both functions apply per-request — they do not control global bandwidth.

limit_rate_after

Sets the maximum amount of data transfer before throttling begins.

Item	Details
Syntax	`limit_rate_after(n, unit)`
Return value	`true` on success, `false` on failure

Parameters

Parameter	Type	Required	Description
`n`	integer	Yes	Maximum data transfer before throttling begins. If `unit` is omitted, `n` is in bytes.
`unit`	char	No	Unit for `n`. Valid values: `K`, `M`, `G` (case-insensitive).

limit_rate

Sets the rate to which data transfer is throttled after the limit_rate_after threshold is reached.

The minimum enforced rate is 50 KB/s. If you specify a lower value, the rate is throttled to 50 KB/s.

Item	Details
Syntax	`limit_rate(n, unit)`
Return value	`true` on success, `false` on failure

Parameters

Parameter	Type	Required	Description
`n`	integer	Yes	Throttled data transfer rate. If `unit` is omitted, `n` is in bytes per second.
`unit`	char	No	Unit for `n`. Valid values: `K`, `M`, `G` (case-insensitive).

Example

Use limit_rate_after and limit_rate together to let a request transfer data at full speed up to a threshold, then cap the rate:

limit_rate_after(100, 'k')
limit_rate(1, 'm')
// The first 100 KB transfers at full speed. After that, the rate is capped at 1 MB/s.