18-29
Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 18 Regulating and Shaping Subscriber Traffic
Queuing PPP Sessions on ATM VCs
shape average percent 20 account user-defined 20 atm
policy-map child
class class2
shape average percent 20 account user-defined 20 atm
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Queuing PPP Sessions on ATM VCs
PPP Session Queuing on ATM Virtual Circuits (VCs) enables you to shape and queue PPP over ATM
(PPPoA) and PPP over Ethernet over ATM (PPPoEoA) sessions to a user specified rate. Multiple
sessions can exist on any ATM VC and have QoS policies applied, or some of the sessions might have
QoS policies while others do not. The router shapes the sum of all PPPoA or PPPoEoA traffic on a VC
so that the subscriber’s connection to the DSLAM does not become congested. Queuing-related
functionality provides different levels of service to the various applications that execute over the PPPoA
or PPPoEoA session.
A nested, 2-level hierarchical service policy is used to configure session shaping directly on the router
using the modular quality of service command-line interface
(MQC). The hierarchical policy consists of
the following:
• Child policy—Defines QoS actions using QoS commands such as the priority, bandwidth, and
police commands.
• Parent policy—Contains only the class-default class with the shape or bandwidth remaining ratio
command configured, or with both commands configured:
–
shape command—Shapes the session traffic to the specified bit rate, according to a specific
algorithm.
–
bandwidth remaining ratio command—Specifies a ratio value that the router uses to
determine how much unused bandwidth to allocate to the session during congestion.
For more information about nested hierarchical policies, see the “Nested Hierarchical Policies” section
on page 13-6.
Note The PPP Session Queuing on ATM VCs feature applies to both PPP terminated aggregation (PTA) and
L2TP access concentrator (LAC) configurations.
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