Color-Aware Configuration For Rate-Limiting Hierarchical Policy - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - POLICY MANAGEMENT CONFIGURATION GUIDE 2010-10-04 Configuration Manual

JunosE 11.3.x Policy Management Configuration Guide

Color-Aware Configuration for Rate-Limiting Hierarchical Policy

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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
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.
class non-preferred parent A
color yellow
class preferred parent A
mark profile cm
parent A
rate-limit A !! a color-aware rate limit
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.
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
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