Brocade Communications Systems Brocate Ethernet Access Switch 6910 - Manual (Page 487)

Brocade 6910 Ethernet Access Switch Configuration Guide 437
53-1002581-01
Quality of Service Commands
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conform-action - Action to take when packet is within the CIR and BC. (There are enough
tokens to service the packet, the packet is set green).
violate-action - Action to take when packet exceeds the CIR and BC. (There are not enough
tokens to service the packet, the packet is set red).
transmit - Transmits without taking any action.
drop - Drops packet as required by violate-action.
new-dscp - Differentiated Service Code Point (DSCP) value. (Range: 0-63)
Default Setting
None
Command Mode
Policy Map Class Configuration
Command Usage
• You can configure up to 16 policers (i.e., class maps) for ingress ports.
• The committed-rate cannot exceed the configured interface speed, and the committed-burst
cannot exceed 16 Mbytes.
• Policing is based on a token bucket, where bucket depth (i.e., the maximum burst before the
bucket overflows) is by specified the committed-burst field, and the average rate tokens are
added to the bucket is by specified by the committed-rate option. Note that the token bucket
functions similar to that described in RFC 2697 and RFC 2698.
• The behavior of the meter is specified in terms of one token bucket (C), the rate at which the
tokens are incremented (CIR – Committed Information Rate), and the maximum size of the
token bucket (BC – Committed Burst Size).
The token bucket C is initially full, that is, the token count Tc(0) = BC. Thereafter, the token
count Tc is updated CIR times per second as follows:
• If Tc is less than BC, Tc is incremented by one, else
• Tc is not incremented.
When a packet of size B bytes arrives at time t, the following happens:
• If Tc(t)-B ≥ 0, the packet is green and Tc is decremented by B down to the minimum value
of 0, else
• else the packet is red and Tc is not decremented.
Example
This example creates a policy called “rd-policy,” uses the class command to specify the previously
defined “rd-class,” uses the set phb command to classify the service that incoming packets will
receive, and then uses the police flow command to limit the average bandwidth to 100,000 Kbps,
the burst rate to 4000 bytes, and configure the response to drop any violating packets.
Console(config)#policy-map rd-policy
Console(config-pmap)#class rd-class
Console(config-pmap-c)#set phb 3
Console(config-pmap-c)#police flow 100000 4000 conform-action transmit
violate-action drop
Console(config-pmap-c)#