Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 483)

• Traffic flagged to the green or "conform" color priority conforms to the committed information rate
(CIR) as defined by the cir-rate variable for the policy-map (refer to Policing parameters on page
483). This rate can be anything from 40000 to 400000000000 bps.
• Traffic flagged as yellow or "exceed" exceeds the CIR, but conforms to the Excess Information Rate
(EIR) defined by the eir-rate variable for the policy-map (refer to Policing parameters on page 483).
This rate can be set from 0 through 400000000000 bps.
• Traffic flagged as red or "violate" are not compared to CIR or EIR and will be dropped.
Using policing parameters, you can define metering rates, such as CIR and EIR, and actions for traffic
flagged as conforming or exceeding the rates. As a simple example, traffic within the "conform" rate
may be sent at a certain CoS priority, traffic flagged at the "exceed" rate may be sent at a lower priority,
and traffic that violates the set rates can be dropped (default and only option).
Policing parameters
Policing parameters provide values for CIR, CBS, EIR, and EBS, for classifying traffic by a specific
class for color-based priority mapping. They also specify specific actions to perform on traffic with a
color-class priority, such as having packet DSCP priority, traffic class (internal queue assignment), or
traffic class (internal queue assignment) set to specific values.
CIR and CBS
The Committed Information Rate (CIR) is the maximum number of bits that a port can receive or send
during one-second over an interface. For CIR, there are two parameters that define the available traffic:
CIR and the Committed Burst Size (CBS). The CIR represents a portion of the interface’s total
bandwidth expressed in bits per second (bps). It cannot be larger than the interface’s total bandwidth.
CBS controls the bursty nature of the traffic. Traffic that does not use the configured CIR accumulates
credits until the credits reach the configured CBS. These credits can be used when the rate temporarily
exceeds the configured CIR. When credits are not available, the traffic is either dropped or subject to
the policy set for the Excess Information Rate (EIR). The traffic limited by the CIR can have its priority,
traffic class, and DSCP values changed.
CIR is mandatory policing parameter for configuring a class map.
cir cir-rate
The cir command defines the value of the CIR as the rate provided in the cir-rate variable. Acceptable
values are in multiples of 40000 in the range 40000-40000000000 bps.
cbs cbs-size
The cbs command defines the value of the CBS as the rate provided in the cbs-size variable.
Acceptable values are 1250-5000000000 bytes in increments of 1 byte.
EIR and EBS
The Excess Information Rate (EIR) provides an option for traffic that has exceeded the CIR. For EIR,
there are two parameters that define the available traffic: the EIR and the Excess Burst Size (EBS). The
EIR and EBS operate exactly like the CIR and CBS, except that they act only upon traffic that has been
passed to the EIR because it could not be accommodated by the CIR. Like the CIR, the EIR provides
an initial bandwidth allocation to accommodate inbound and outbound traffic. Like the CBS, the
bandwidth available for burst traffic from the EBS is subject to the amount of bandwidth that is
accumulated during periods when traffic allocated by the EIR policy is not used. When inbound or
outbound traffic exceeds the bandwidth available (accumulated credits or tokens), it is be dropped. The
traffic rate limited by the EIR can have its priority, traffic class, and DSCP values changed.
EIR and EBS parameters are optional policing parameters. If not set, they are considered disabled.
eir eir-rate
Policing parameters
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