Cisco Cisco IOS Software Release 12.2(27)SBC

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The MQC—Traffic Shaping Overhead Accounting for ATM feature enables a broadband aggregation 
system (BRAS) to account for various encapsulation types when applying quality of service (QoS) 
functionality to packets. Typically, in Ethernet digital subscriber line (DSL) environments, the 
encapsulation from the router to the digital subscriber line access multiplexer (DSLAM) is Gigabit 
Ethernet and the encapsulation from DSLAM to customer premises equipment (CPE) is ATM. ATM 
overhead accounting enables the router to account for ATM encapsulation on the subscriber line and for 
the overhead added by cell segmentation. This enables the service provider to prevent overruns at the 
subscriber line and ensures that the router executes QoS features on the actual bandwidth used by ATM 
packets.

Your Cisco IOS software release may not support all of the features documented in this module. To reach 
links to specific feature documentation in this module and to see a list of the releases in which each feature is 
supported, use the 

.

Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS 
software image support. To access Cisco Feature Navigator, go to 

. An 

account on Cisco.com is not required.