Advanced Configuration and Management Guide

intervals, the port receives less than 500000 bits in each interval. However, the port receives more than 500000 bits during the third and fourth one-second intervals, and consequently drops the excess traffic.

The Fixed Rate Limiting policy allows up to 500000 bits

(62500 bytes) of inbound traffic during each one-second interval.

Once the maximum rate is reached, all additional traffic within the one-second interval is dropped.

One-second

One-second

One-second

One-second

interval

interval

interval

interval

500000 bps (62500 bytes)

Zero bps

Beginning of one-second interval

Figure 4.1 Fixed Rate Limiting

NOTE: The software counts the bytes by polling statistics counters for the port every 10 milliseconds, which provides 100 readings each second. Due to the polling interval, the Fixed Rate Limiting policy has an accuracy of within 1% of the port’s line rate. It is therefore possible for the policy to sometimes allow more traffic than the limit you specify, but the extra traffic is never more than 1% of the port’s line rate.

Configuring Fixed Rate Limiting

To configure a Fixed Rate Limiting policy, enter a command such as the following at the configuration level for a port:

HP9300(config-if-1/1)# rate-limiting input fixed 500000

This command configures a Fixed Rate Limiting policy that allows port 1/1 to receive a maximum of 500000 bps (62500 bytes per second). If the port receives additional bytes during a given one-second interval, the port drops all inbound packets on the port until the next one-second interval starts.

Syntax: [no] rate-limiting input output fixed <rate>

The input output parameter specifies whether the rate limit applies to inbound or outbound traffic on the port.

The <rate> parameter specifies the maximum rate for the port. Specify the rate in bits per second. You can specify from 1 up to any number. There is no default.

NOTE: If you specify a number that is larger than the port’s line rate, the traffic will never cause the policy to go into effect.

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