Specifications

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Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.3.0XO(15.1(1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
police
Switch(config-pmap-c)# police 8000 1000 1000 conform-action transmit exceed-action
set-qos-transmit 1 violate-action drop
Switch(config-pmap-c)# exit
Switch(config-pmap)# exit
Switch(config)# interface gigabitethernet 6/1
Switch(config-if)# service-policy output police-setting
Switch(config-if)# end
In this example, the initial token buckets starts full at 1000 bytes. If a 450-byte packet arrives, the packet
conforms because enou gh byt es are avail able in the conform token buc ket. The c onform act ion (send) is
taken by the packet and 450 bytes are remove d from the conform token bucke t (leaving 550 bytes).
If the next packet arrives 0.25 seconds later, 250 bytes are added to the conform token bucket
((0.25 * 8000)/8), leaving 800 bytes in the conform token bucket. If the next packet is 900 bytes, the
packet does not conform because only 800 bytes are available i n the conform token bucket.
The exceed token bucket, which starts full at 1000 bytes (as specified by the excess burst size) is then
checked for available bytes. Because enough bytes are available in the exceed token bucket, the exceed
action (set the QoS transmit value of 1) is taken and 900 bytes are taken from the exceed bucket (leaving
100 bytes in the exceed token bucket .
If the next packet arrives 0.40 seconds later, 400 bytes are added to the token buckets ((.40 * 8000)/8).
Therefore, the conform to ken bucket now has 1000 bytes (the maximum number of tokens availa ble in
the conform bucket) and 200 bytes overf low the conform token bucket (because it only 200 bytes we re
needed to fill the conform token bucket to capacity). These overflow bytes are placed in the exceed token
bucket, giving th e excee d token buc ket 300 byte s.
If the arriving packet is 1000 bytes, the packet conforms because enough bytes are available in the
conform token bucket . The conf orm action (transmit) is taken by the pa cket and 1000 bytes are removed
from the conform token bucket (leav ing 0 bytes).
If the next packet arrives 0.20 secon ds later, 200 bytes are added to the token bucket ((.20 * 8000)/8) .
Therefore, the confor m bucket n ow has 200 byte s. If the arriving pa cket is 400 by tes, the pa cket doe s not
conform because only 200 bytes are available in the conform bucket. Similarly, the packet does not
exceed because only 300 bytes are availa ble in the exceed bu cket. Th erefore, the packet violates a nd the
violate action (drop) is taken.
Related Commands Command Description
police ( per cen t) Configures traffic policing on the basis of a percentage of
bandwidth available on an inte rface.
police (two rates) Configures traffic policing using two rates, the committed
information rate (CIR) and the peak information rate (PIR).
policy-map Creates or mod ifies a policy map that can be a ttached to multiple
ports to specify a service policy and to enter policy-map
configuration mod e.
service-policy (policy-map
class)
Creates a service policy that is a quality of service (QoS) policy
within a policy map.
show policy-map Displays information about the policy map.
show policy-map interfac e Displays the statistics and configurations of the input and output
policies that are attached to an interface.