Hierarchical Policers On Acx Series Routers Overview - Juniper ACX1000 Configuration Manual

ACX Series Universal Access Router Configuration Guide

Hierarchical Policers on ACX Series Routers Overview

920
On ACX Series routers, two-level ingress hierarchical policing is supported. Single-level
policers define a single bandwidth profile that is used by multiple traffic flows with
different priorities. Two-level policers enable a single bandwidth profile to be optimally
used for multiple traffic flows, based on bandwidth and priority needs of a network.
Typically, multiple traffic flows can share a single policer instance. With single-level
policers, you cannot adminster the method using which the committed information rate
(CIR) and the peak information rate (PIR) values specified in the bandwidth profile are
shared across different flows. For example, in a certain network deployment, you might
want an equal or even distribution of CIR across the individual flows. In such a scenario,
you cannot accomplish this requirement using single-level policers and need to configure
aggregate or hierarchical policers.
NOTE: Hierarchical policers is not applicable on ACX5048 and ACX5096
routers.
Hierarchical policers control the sharing of an aggregate traffic rate across multiple
micro-flows, which constitute the aggregate flow or the macro-flow. Micro-flows are
defined and matched using firewall filter rules and the action of these rules point to a
macro-policer. This macro- policer or aggregate policer determines the amount of
aggregate bandwidth that can be used by the micro-flows that are associated with it.
You can control the bandwidth to be utilized among the micro-flows in different ways.
NOTE: The hierarchical policing mechanism on ACX routers is different from
the hierarching policing capability supported on MX Series routers. On MX
Series routers, with a hierarchical policer, only one child or subordinate policer
can be configured under a parent, top-level policer, whereas on ACX Series
routers, you can aggregate and specify multiple child policers under a single
parent policer. The hierarchical policing methodology on ACX routers is also
called aggregate policing.
Policers are used to enforce bandwidth profiles on the transmitted traffic. A bandwidth
profile is configured for each user based on the service level agreement (SLA) and the
subscription plan that has been requested by the user from the service or enterprise
provider. A bandwidth profile is defined using the following parameters:
Committed information rate (CIR) denoted in bits per second (bps).
Committed burst size (CBS) denoted in bytes.
Excess information rate (EIR) denoted in bps.
Excess burst size (EBS) denoted in bytes.
Color mode (CM) can contain only one of two possible values, color-blind or
color-aware. In color-aware mode, the local router can assign a higher packet loss
priority, but cannot assign a lower packet loss priority. In color-blind mode, the local
Copyright © 2017, Juniper Networks, Inc.