Implementing Traffic Policers On Ex 9200 Switches; Policer Implementation Overview - Juniper EX9200 Features Manual

CHAPTER 5
Implementing Traffic Policers on EX 9200
Switches

Policer Implementation Overview

Copyright © 2016, Juniper Networks, Inc.
Policer Implementation Overview on page 25
Understanding the Benefits of Policers and Token Bucket Algorithms on page 28
Determining Proper Burst Size for Traffic Policers on page 30
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The Juniper Networks Junos
policers:
Single-rate two-color policer — The most common policer. Single-rate means that
there is only a single bandwidth and burst rate referenced in the policer. The two colors
associated with this policer are red (nonconforming) and green (conforming).
Single-rate three-color policer — Similar to the single-rate two-color policer with the
addition of the color yellow. This type also introduces the committed information rate
(CIR) and a committed burst rate (CBR).
Two-rate three-color policer — Builds off of the single-rate three-color policer by adding
a second rate tier. Two-rate means there is an upper bandwidth limit and associated
burst size as well as a peak information rate (PIR) and a peak burst rate (PBS).
There are two types of token bucket algorithms that can be used, depending on the type
of policer that is applied to network traffic. Single-rate two-color policers use the single
token bucket algorithm to measure traffic flow conformance to a two-color policer rate
limit. Single-rate three-color policers and two-rate three-color policers both use the dual
token bucket algorithm to measure traffic flow conformance to a three-color policer rate.
The main difference between these two token bucket algorithms is that the single token
bucket algorithm allows bursts of traffic for short periods, whereas the dual token bucket
algorithm allows more sustained bursts of traffic. (The remainder of this topic discusses
the single token bucket algorithm.)
To configure a policer, you need to set two parameters:
Bandwidth limit configured in bps (using the bandwidth-limit statement)
Burst size configured in bytes (using the burst-size-limit statement)
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operating system (Junos OS) supports three types of
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