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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
QoS Bandwidth Allocation
QoS Bandwidth Allocation
The DBE supports QoS bandwidth allocation. The DBE has the ability to limit excess traffic beyond the
allocated bandwidth by performing session-based policing. For information on the different types of
policing performed by the DBE, see the “H.248 Traffic Management Package Support” section on
page 5-1, the “RTCP Policing” section on page 5-4, and the “Two-Rate Three-Color Policing and
Marking” section on page 5-5.
RTCP Policing
An SBC session may be of two types, media or signaling. The media portion of the call comprises the
Real-time Transport Protocol (RTP) stream and, optionally, a Real-time Control Protocol (RTCP)
stream. Calls typically have both a RTP and RTCP stream.
Each session may be subject to policing. RTCP sessions are not explicitly configured using the H.248
protocol and therefore cannot have their policing parameters set. Instead, the policing parameters for
RTCP sessions are derived from the corresponding RTCP flows depending on the usage of the ETSI TS
102 333 Traffic Management (Tman) package.
For more information on the Tman package, see the “H.248 Traffic Management Package Support”
section on page 5-1.

RTCP Policing Using Tman Package

The H.248 Tman package is used to set the sustained data rate (tman/sdr) and the policing (tman/pol)
properties on the RTCP session. The RTCP session derives its policing rate from the H.248 Tman
package as follows:
• When the sustained data rate (tman/sdr) has been defined in bytes per second, the RTCP rate limiting
is 5 percent of the sustained data rate (sdr).
• However, if the RTCP r ate obtained b y taking 5 percent of the sustained data rate is below 208 bytes
per second, then a minimum RTCP rate of 208 is used instead. There is no associated warning for
this action.
Note When the policing (tman/pol) has been set to OFF, the RTCP session is not rate-limited.

RTCP Policing Not Using Tman Package

RTCP policing can be implemented by not setting any of the properties of the H.248 Tman package.
When the tman/sdr property is not specified, the RTCP rate limiting is set at 5 percent of the codec for
the RTP stream.