Class Fair Hierarchical Policing (CFHP)
Quality of Service Guide 867
For ingress policing, each offered packet has a priority and a profile state. The priority is used
by the policer to choose either the high or low priority PIR threshold-be. Every offered packet
is either priority high or priority low. The offered profile state defines how a packet will
interact with the policers CIR bucket state. The combinations of priority and initial profile are
as follows:
• Offered priority low, undefined profile
• Offered priority low, explicit profile in
• Offered priority low, explicit profile out
• Offered priority high, undefined profile
• Offered priority high, explicit profile in
• Offered priority high, explicit profile out
The possible output results for the ingress policer are:
• Output green (in-profile)
• Output yellow (out-of-profile)
• Output red (discard)
In order to conserve counter resources, the system supports a policer stat-mode command that
is used to identify what counters are actually needed for the policer. Not every policer will
have a CIR defined, so the output green/yellow states will not exist. Also, not every policer
will have both high and low priority or explicit in-profile or out-of-profile offered traffic
types. Essentially, the stat-mode command allows the counter resources to be allocated based
on the accounting needs of the individual policers.
Setting the stat-mode does not modify the packet handling behavior of the policer. For
example, if the configured stat-mode does not support in-profile and out-of-profile output
accounting, the policer is not blocked from having a configured CIR rate. The CIR rate will
be enforced, but the amount of in-profile and out-of-profile traffic output from the policer will
not be counted separately (or maybe not at all based on the configured stat-mode).
A policer is created with minimal counters sufficient to provide total offered and total
discarded (the total forwarded is computed as the sum of the offered and discarded counters).
The stat-mode is defined within the sap-ingress or sap-egress QoS policy in the policer
context. When defining the stat-mode, the counter resources needed to implement the mode
must be available on all forwarding planes where the policer has been created using the QoS
policy unless the policer instance has a stat-mode override defined. You can see the resources
used and available by using the tools dump resource-usage card fp command. If insufficient
Note: When de1out is enabled, DEI = 0 is considered as undefined profile and DEI = 1 is
considered the same as profile out
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