Color Modes For Three-Color Policers; Color-Blind Mode; Color-Aware Mode - Juniper EX9200 Features Manual

Traffic Policers Feature Guide for EX9200 Switches

Color Modes for Three-Color Policers

Color-Blind Mode

Color-Aware Mode

150
Three-color policers—both single-rate and two-rate three-color policer schemes—can
operate in either of two modes:
Color-Blind Mode on page 150
Color-Aware Mode on page 150
In color-blind mode, the three-color policer assumes that all packets examined have not
been previously marked or metered. If you configure a three-color policer to be color-blind
instead of color-aware, the policer ignores preexisting color markings that might have
been set for a packet by another traffic policer configured at a previous network node.
In color-aware mode, the three-color policer assumes that all packets examined have
been previously marked or metered. In other words, the three-color policer takes into
account any coloring markings that might have been set for a packet by another traffic
policer configured at a previous network node. At the node where color-aware policing
is configured, any preexisting color markings are used in determining the appropriate
policing action for the packet.
In color-aware mode, the three-color policer can increase the packet loss priority (PLP)
level of a packet, but never decrease it. For example, if a color-aware three-color policer
meters a packet with a medium PLP marking, it can raise the PLP level to high, but cannot
reduce the PLP level to low.
For two-rate, three-color policing, the Junos OS uses two token buckets to manage
bandwidth based on the two rates of traffic. For example, two-rate policing might be
configured on a node upstream in the network. The two-rate policer has marked a packet
as yellow (loss priority medium-low). The color-aware policer takes this yellow marking
into account when determining the appropriate policing action. In color-aware policing,
the yellow packet would never receive the action associated with either the green packets
or red packets. This way, tokens for violating packets are never taken from the metering
token buckets at the color-aware policing node.
Copyright © 2016, Juniper Networks, Inc.