Simultaneous Qos Policy Map On An Interface And Ppp Session - Cisco 10000 Series Configuration Manual

Simultaneous Policy Maps
Simultaneous policy maps provide multiple levels of QoS hierarchy that can shape traffic at different
points of congestion in the Layer 2 network.
This chapter describes simultaneous policy maps on the Cisco 10000 series router and consists of the
following topics:
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Simultaneous QoS Policy Map on an Interface and PPP Session

The Simultaneous QoS Policy Map on Interface and PPP Session—A-DSLAM Case feature allows the
broadband aggregation system (BRAS) to provide multiple levels of QoS hierarchy that shape traffic at
different points of congestion in the Layer 2 network. This enables the BRAS to avoid congestion in
downstream links within the network.The BRAS prioritizes the traffic based on the subscriber's
contracted bandwidth and subscribed services.
Using simultaneous policy maps, you can apply QoS at the session level and at the Ethernet subinterface
or PVC level for a single ATM PVC with two or more PPPoE sessions. At the session level, you can
configure the BRAS to mark any traffic above a specified rate with a particular designation. When the
traffic arrives at the Ethernet subinterface or ATM PVC, the BRAS uses the specified designation to give
a higher drop probability to packets marked with the designation. As a service provider, this enables you
to ensure that each of the separate sessions receives a minimum level of the subinterface or PVC capacity
and allows any one session to receive the full capacity of the subinterface or PVC if the other sessions
are idle.
When configuring simultaneous policy maps, you configure policy maps at the interface and session
levels in a serial fashion: one policy applied to a VAI or a LAC session and another policy applied to an
ATM PVC or an Ethernet-based subinterface as the following describes:
OL-7433-09
Simultaneous QoS Policy Map on an Interface and PPP Session, page 14-1
Restrictions for Simultaneous Policy Maps, page 14-4
Configuring Simultaneous Policy Maps, page 14-5
Configuration Examples for Simultaneous Policy Maps, page 14-14
Verifying Simultaneous Policy Maps, page 14-18
Verification Examples for Traffic Policing, page 14-19
C H A P T E R
Cisco 10000 Series Router Quality of Service Configuration Guide
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