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Cisco AVVID Network Infrastructure Enterprise Quality of Service Design
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Chapter 4 QoS in an AVVID-Enabled Wide-Area Network
QoS Recommendations for WAN Aggregation Routers
Modular QoS Command-Line Interface
The Modular QoS CLI (MQC) was developed with the objective of making QoS configuration more
consistent across platforms. MQC is a syntax structure for QoS policies, consisting of three parts:
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class-map statement-- classifies traffic
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policy-map statement-- defines the treatment for the various classes of traffic
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service-policy statement--binds the policy to an interface and specifies direction
MQC offers simplicity and consistency in policy definition as its main advantages. MQC also supports
the ability to define policies within policies (hierarchical policies). Hierarchical policies are essential for
deploying AVVID policies on distributed Frame Relay WAN aggregators. Also, MQC has associated
with it an SNMPv2 MIB (CISCO-CLASS-BASED-QOS-MIB), which provides detailed, granular
visibility for QoS monitoring and management.
Tip
For more information, see Modular Quality of Service Command Line Interface in the Cisco IOS Quality
of Service Solutions Configuration Guide, Release 12.2.
For hierarchical policies, see the Traffic Policy as a QoS Policy (Hierarchical Traffic Policies) Example.
And for the MIB, see the Cisco Class-Based QoS Configuration and Statistics MIB.
QoS Recommendations for WAN Aggregation Routers
This section contains information about using QoS in WAN aggregation routers. It covers the following:
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Classifying and Provisioning for Voice on the WAN Edge
On the WAN edges (both at the WAN aggregator and the remote-branch), voice traffic needs to be
assigned to an LLQ and voice control traffic needs a minimum bandwidth guarantee (CBWFQ).
The bandwidth required for LLQ traffic can be expressed quantitatively (in absolute kbps) or it can be
expressed relatively (as of IOS 12.2.2T) using the percent keyword. This keyword can enable increased
modularity of configuration and simplification of management. Expressing the bandwidth reservation in
absolute kbps or as a percentage is at the administrator's discretion.
Note
If the percent keyword is used for one LLQ provisioning, then it must be used for all other LLQ
provisioning (as in the case of voice and video). Likewise, if an LLQ is provisioned in terms of absolute
kbps, then any additional LLQs must also be provisioned in absolute kbps.