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JUNOSe 11.1.x Policy Management Configuration Guide
Color-Aware Configuration for Rate-Limiting Hierarchical Policy
Common to many rate-limit hierarchies is a large aggregate rate limit that receives
packets from many smaller individual rate limits. An individual rate limit can mark
a packet yellow but, if few individual flows are active, the aggregate rate limit is likely
to try to promote it to green, overriding the individual rate limit. For this reason, rate
limits never promote packets in color; color-aware rate limits use the incoming color
in their algorithm, but the final result is always equal to or less than the initial packet
color.
Rate-limit profiles for rate-limit hierarchies include a non-default configuration option
for color-aware. For two-rate rate limits this option enables the color-aware algorithm.
If hierarchical, TCP-friendly one-rate rate limits have a color-aware algorithm defined.
In the following color-aware example, the non-preferred packets do not take any
green tokens from rate-limit A, leaving them all for preferred packets. Preferred
packets may take green and also take yellow tokens (which reduces the flow of
non-preferred). In this way the non-preferred packets do not reduce the number of
green preferred packets, only the number of yellow preferred packets; preferred
packets are then marked from a color-mark profile.
The color-mark profile translates the packet color, which is independent of its type,
to a type-dependent mark for ToS or EXP and applies it to a packet after it has exited
the rate-limit hierarchy. If no translation is configured for a color, then packets of
that color are not changed.
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Hierarchical Rate Limits Overview
host1(config-color-mark-profile)# yellow-mark TOS3
host1(config-color-mark-profile)# red-mark TOS3
host1(config--color-mark-profile)# exit
host1(config)# policy-list TOS1_oversubsribed
host1(config-policy-list)# classifier-group A parent-group S
host1(config-policy-list-classifier-group)# rate-limit-profile indiv
host1(config-policy-list-classifier-group)# mark profile A
host1(config--classifier-group)# exit
host1(config-policy-list)# classifier-group B parent-group S
host1(config-policy-list-classifier-group)# rate-limit-profile indiv
host1(config-policy-list-classifier-group)# mark profile BC
host1(config--classifier-group)# exit
host1(config-policy-list)# classifier-group C parent-group S
host1(config-policy-list-classifier-group)# rate-limit-profile indiv
host1(config-policy-list-classifier-group)# mark profile BC
host1(config-policy-list-classifier-group)# exit
host1(config-policy-list)# parent-group S
host1(config-policy-list-parent-group)# rate-limit-profile S
host1(config-policy-list-parent-group)# exit
class non-preferred parent A
color yellow
class preferred parent A
mark profile cm
parent A
rate-limit A !! a color-aware rate limit
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