Chapter 13 Configuring Quality Of Service; Understanding Ml-Series Qos - Cisco ONS 15454 Software Feature And Configuration Manual

Configuring Quality of Service
This chapter describes the QoS features built into your ML-Series card and how to map QoS scheduling
at both the system and interface levels. This chapter contains the following major sections:
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Understanding ML-Series QoS

The ML-Series card incorporates QoS features to provide control over access to network bandwidth
resources. This control enables providers to implement priorities specified in Service Level Agreements
(SLAs) and offers tools to enable traffic engineering.
The ML-Series QoS provides the ability to classify each packet in the network based on its interface of
arrival, bridge group, class of service (CoS), IP precedence, and IP differentiated services code points.
When classified, further QoS functions can be applied to each packet as it traverses the network.
Policing is also provided by the ML-Series card to ensure that no attached equipment submits more than
a pre-defined amount of bandwidth into the network. This feature limits the bandwidth available to a
customer, and provides a mechanism to support traffic engineering.
Priority marking allows Ethernet IEEE 802.1P CoS bits to be marked, as they exit the ML-Series card.
This feature operates on the outer IEEE 802.1P tag when coupled with QinQ.
Per class flow queuing is provided to enable fair access to excess network bandwidth, and low latency
queuing is supported for voice traffic. It allows allocation of bandwidth to support service-level
agreements and ensure applications with high network resource requirements are adequately served.
Buffers are allocated to queues dynamically from a shared resource pool. The allocation process
incorporates the instantaneous system load as well as the allocated bandwidth to each queue to optimize
buffer allocation to each queue.
The ML-Series card uses an advanced Weighted Deficit Round Robin (WDRR) scheduling process to
provide fair access to excess bandwidth as well as guaranteed throughput to each class flow.
Admission control is a process that is invoked each time that service is configured on the ML-Series card
to ensure that the card's available QoS resources are not overcommitted. In particular, admission control
ensures that no configurations are accepted where a sum of the committed bandwidths on an interface
exceed the total bandwidth of that interface.
Cisco ONS 15454 SONET/SDH ML-Series Multilayer Ethernet Card Software Feature and Configuration Guide, R4.0
78-15224-02
Understanding ML-Series QoS, page 13-1
Configuring QoS, page 13-2
ML-Series QoS Examples, page 13-7
Monitoring and Verifying QoS, page 13-8
C H A P T E R
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