Configuring Fixed Rate Limiting - Foundry Networks Switch and Router Installation And Configuration Manual

500000 bps (62500 bytes)
Figure 14.1 Fixed Rate Limiting
NOTE: The software counts the bytes by polling statistics counters for the port every 100 milliseconds, which
provides 10 readings each second. Due to the polling interval, the Fixed Rate Limiting policy has an accuracy of
within 10% 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 10% 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:
BigIron(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.
Displaying Fixed Rate Limiting Information
To display configuration information and statistics for Fixed Rate Limiting, enter the following command at any
level of the CLI:
BigIron(config)# show rate-limiting fixed
December 2000
One-second
Zero bps
Beginning of
one-second
interval
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
interval interval
IronClad Rate Limiting
One-second One-second
interval interval
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