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Cisco 10000 Series Router Quality of Service Configuration Guide
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Chapter 20 Configuring Quality of Service for MPLS Traffic
MPLS CoS Multi-VC Mode
Benefits of MPLS CoS Multi-VC Mode
The MPLS CoS Multi-VC Mode feature has the following benefits:
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Ensures effective deployment of differentiated service classes in an MPLS-enabled ATM network
•
Leverages the use of existing ATM infrastructures
Restrictions for MPLS CoS Multi-VC Mode
The MPLS CoS Multi-VC Mode feature has the following restrictions:
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A multi-VC service group can have up to four LVCs.
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The Cisco 10000 series router supports a maximum of 500 LVC service groups.
•
The Cisco 10000 series router does not support available bit rate (ABR) for ATM VCs. Therefore,
the router also does not support ABR LVCs.
•
All LVCs and the control-VC share the same QoS policy. Any QoS policy changes are applied to the
subinterface. All LVCs will then automatically share the new policy.
Prerequisites for MPLS CoS Multi-VC Mode
The MPLS CoS Multi-VC Mode feature has the following requirements:
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The Cisco 10000 series router must be running Cisco IOS Release 12.0(27)S or later releases.
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The performance routing engine (PRE), part number PRE1 must be installed in the router’s chassis.
•
To use MPLS QoS to full advantage in your network, the following functionality must be supported:
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Multiprotocol Label Switching (MPLS)—The standardized label switching protocol defined by
the Internet Engineering Task Force (IETF).
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Cisco Express Forwarding (CEF)—An advanced Layer 3 IP switching technology that
optimizes performance and scalability in networks that handle large volumes of traffic and
exhibit dynamic traffic patterns.
–
Asynchronous Transfer Mode (ATM)—International standard for cell relay in which multiple
service types (such as voice, video, or data) are conveyed in fixed-length cells. ATM signaling
is required if you use ATM interfaces in your network.
•
The following QoS features are required:
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MPLS CoS Multi-VC Mode to provide QoS functionality on ATM interfaces in a service
provider MPLS-enabled network.
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Class-based weighted fair queueing (CBWFQ) to allocate bandwidth fairly to all network
traffic.
–
Weighted random early detection (WRED) to configure different discard priorities or classes of
service using the MPLS experimental field in the MPLS packet header.