Cisco Systems ASR 1000 Two-Rate Three-Color Policing and Marking

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Cisco IOS XE Integrated Session Border Controller Configuration Guide for the Cisco ASR 1000 Series Aggregation Services Routers

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Chapter 5 Quality of Service and Bandwidth Management Two-Rate Three-Color Policing and Marking

Two-Rate Three-Color Policing and Marking

Traffic policing is a traffic regulation mechanism that is used to limit the rate of traff ic streams. Policing

allows you to control the maximum rate of traffic sent or received on an interface. When the traffic rate

exceeds the configured maximum rate, policing drops or re-marks the excess traffic.

The ETSI TS 102 333 Traffic Management (Tman) package defined a number of properties to allow

traffic policing to be explicitly enabled. However, because the current H.248 standard only supported

specifying one rate with a traffic flow, the only action available in the H.248 standard for

non-conforming packets had been to discard them. (See the “Enhanced Event Notification and Auditing”

section on page 11-2).

The Two-Rate Three-Color Policing and Marking feature is an enhancement to how the DBE polices

traffic flow by introducing two-rate policing and three-color marking.

The DBE previously supported three tman properties—pol (policing), sdr (sustainable data rate), and

mbs (maximum burst size). In supporting the Two-Rate Three-Color Policing and Marking feature, the

DBE uses one additional property of the ETSI TS 102 333 Traffic Management (Tman) package:

pdr (peak data rate)—Defines the peak data rate in bytes per second that is permitted for the stream.

See the “H.248 Traffic Management Package Support” section on page 5-1 for more information on the

tman properties.

All of the following conditions must occur to enable the Two-Rate Three-Color Policing and Marking

feature for a specific flow:

• The DSCP value is provisioned via diffserv package during call setup.

• The sdr and mbs are provisioned via the Tman package during call setup. (The mbs property is used

for pdr policing as well and has an assumed minimal value of 1500 bytes.)

• Two DSCP values (control and marker DSCPs) and the pdr coefficient are configured via the

control-dscp marker-dscp pdr-coefficient CLI.

• The control-dscp value configured must match the diffserv DSCP value for a specific flo w to enable

the Two-Rate Three-Color Policing and Marking feature.

If any one of the conditions is not met, this feature is not enabled for the flow.

In the Two-Rate Three-Color Policing and Marking feature, only two rates—sdr and pdr—allow traffic

to be policed into three categories of traffic, which are handled as follows:

• Traffic conforming to both sdr and pdr.

These packets are colored using the DSCP value provisioned via the H.248 diffserv package; that is,

H.248 passes the DSCP value. These packets are forwarded and the DSCP value comes from the

H.248 diffserv package.