Brocade Communications Systems 6650 Handling packets that exceed the rate limit, Dropping packets

Handling packets that exceed the rate limit

1. Create an adaptive rate limiting traffic policy. Enter command such as the following:

Brocade(config)# traffic-policy adap rate-limit adaptive cir 1000 cbs 1000 pir 2000 pbs 10000 exceed-action drop

2.Create an IPv4 extended ACL or IPv6 ACL that includes the traffic policy and 802.1p priority matching value. Enter a command such as the following:

Brocade(config)# access-list 136 permit ip any any 802.1p-priority matching 3 traffic-policy adap

3. Bind the ACL to an interface. Enter commands such as the following,.

Brocade(config)# interface ethernet 1/1/7

Brocade(config-if-e10000-1/1/7)# ip access-group 136 in

Brocade(config-if-e10000-1/1/7)# exit

Use the show access-list accounting command to view accounting statistics.

Handling packets that exceed the rate limit

For every traffic policy, you can specify what action to take on packets that exceed the configured rate limit. For both types of policies (fixed and adaptive rate limiting), you can specify one of the following actions:

•Drop packets that exceed the limit.

•Forward packets at the lowest priority level.

NOTE

For information on the how to configure a rate limit in fixed rate limiting, see“Configuring fixed rate limiting” on page 143. For information on the how to configure a rate limit in adaptive rate limiting, see“Configuring adaptive rate limiting” on page 144.

Dropping packets

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.

The following example shows the drop action applied to a fixed rate limiting policy.

Brocade(config)# traffic-policy TPD1 rate-limit fixed 10000 exceed-action drop

The above command sets the fragment threshold at 10000 packets per second. If the port receives more than 10000 packets in a one-second interval, the device drops the excess fragments.

Syntax: [no] traffic-policy TPD-namerate-limit fixed cir-valueexceed-action drop

The following example shows the drop action applied to an adaptive rate limiting policy.

Brocade(config)# traffic-policy TPDAfour rate-limit adaptive cir 10000 cbs 1600 pir 20000 pbs 4000 exceed-action drop

Brocade ICX 6650 Security Configuration Guide	147
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