Brocade FastIron Ethernet Switch Traffic Management Guide - Manual (Page 71)

Specifying the action to be taken for packets that are over the limit
You can specify the action to be taken when packets exceed the configured CIR value for fixed rate
limiting, or the CIR, CBS, PIR, and PBS values for adaptive rate limiting. You can specify one of the
following actions:
• Drop packets that exceed the limit.
• Permit packets that exceed the limit and forward them at the lowest priority level.
Dropping packets that exceed the limit
The ultimate action that a device can take on a packet is to drop the packet. You can apply the drop
action on packets that exceed the rate limit in both fixed rate limiting and adaptive rate limiting traffic
policies. In fixed rate limiting policies, a packet is dropped only when the packet rate exceeds the CIR
limit. Whereas, in adaptive rate limiting policies, a packet is dropped only when the packet rate exceeds
PIR limit + PBS within one second.
This section shows some example configurations and provides the CLI syntax for configuring a port to
drop packets that exceed the configured limits for rate limiting.
The following example shows a fixed rate limiting configuration.
device(config)#traffic-policy TPD1 rate-limit fixed 10000 exceed-action drop
The command sets the fragment threshold at 10,000 packets per second. If the port receives more than
10,000 packets in a one-second interval, the device drops the excess fragments.
Syntax: [no] traffic-policy TPDname rate-limit fixed cir value exceed-action drop
The following example shows an adaptive rate limiting configuration.
device(config)#traffic-policy TPDAfour rate-limit adaptive cir 10000 cbs 1600 pir
20000 pbs 4000 exceed-action drop
The command configures an adaptive rate limiting policy that enforces a guaranteed committed rate of
10000 kbps (10000 pkts/s in ICX 6650) and allows bursts of up to 1600 bytes (1600 packets in ICX
6650). It also enforces a peak rate of 20000 kbps (20000 pkts/s in ICX 6650) and allows bursts of 4000
bytes (4000 packets in ICX 6650) above the PIR limit. If the port receives additional bits during a given
one-second interval, the port drops all packets on the port until the next one-second interval starts.
Syntax: [no] traffic-policy TPDname rate-limit adaptive cir cirvalue cbs cbsvalue pir pirvalue pbs
pbsvalue exceed-action drop
Permitting packets that exceed the limit
This section shows some example configurations and provides the CLI syntax for configuring a port to
permit packets that exceed the configured limit for rate limiting.
The following example shows a fixed rate limiting configuration.
device(config)#traffic-policy TPD1 rate-limit fixed 10000 exceed-action permit-at-low-
pri
The command sets the fragment threshold at 10,000 packets per second. If the port receives more than
10,000 packets in a one-second interval, the device takes the specified action. The action specified with
this command is to permit excess fragments and forward them at the lowest priority level.
Syntax: [no] traffic-policy TPDname rate-limit fixed cirvalue exceed-action permit-at-low-pri
The following example shows an adaptive rate limiting configuration.
device(config)#traffic-policy TPDAfour rate-limit adaptive cir 10000 cbs 1600
pir 20000 pbs 4000 exceed-action permit-at-low-pri
Specifying the action to be taken for packets that are over the limit
FastIron Ethernet Switch Traffic Management Guide 69
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