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Transmit-unconditional packets entering a color-aware rate limit uses the color on
the packet for the rate-limit algorithm. Doing this ensures that the color-aware rate
limit depletes tokens from the token buckets to account for these packets.
Every packet sent through a rate-limit hierarchy is either dropped inside the hierarchy
or emerges with a green, yellow, or red color assigned to it by the rate-limit hierarchy.
The color depends on the last rate limit in the hierarchy that owned the packet and
all prior rate limits. The green, yellow, or red classification applies to packets of any
type and is not interface-type dependent.
A packet that has traversed the hierarchy either has been dropped or emerges with
a color (green, yellow or red). This final color can be used by a mark rule with a
color-mark profile to select the ToS marking for the packet. Because this operation
is interface-type dependent, the actual value is configured where the packet entered
the hierarchy; however, the color is set by the entire rate-limit hierarchy.
We recommend that all rate-limit profiles that receive transmit unconditional packets
should be color-aware. If not color-aware, yellow transmit unconditional packets are
processed through both the green and yellow token buckets; if the green rate is low,
this causes an oversubscription of transmit unconditional packets and leads to
saturation. By making the rate limit color-aware, the yellow transmit unconditional
packets ar counted only against the yellow token bucket.
Related Topics
Percent-Based Rates for Rate-Limit Profiles Overview
Percent-based rate-limit profiles enable you to divide the reference rate as percentages
instead of specific values. You can specify the reference rate on each interface and
specify these rates in terms of percentage of this reference rate within the rate-limit
profile to derive the appropriate rate. This enables you to define rate-limit profiles
with rates in terms of percentage and bursts in terms of milliseconds.
You can use percent-based rate-limit profiles to:
color
color-aware
color-mark-profile
green-mark
red-mark
yellow-mark
Configure rates in rate-limit profiles based on a percentage of a parameter. You
can assign values to these parameters at the time of attachment, which enables
you to use the same policy for multiple interfaces with different parameter values.
Specify burst sizes in milliseconds when you configure percent-based rate-limits.
Provide a generic way to configure and use policy parameters. You can use
parameter names when you create policy objects and defer assigning values to
these parameters until policy attachment. This enables you to share policy objects
by attaching the same policy at multiple interfaces with different parameter
Chapter 5: Creating Rate-Limit Profiles
Percent-Based Rates for Rate-Limit Profiles Overview
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