Qos Terminology - Cisco 6500 Series Software Configuration Manual

Chapter 31 Configuring PFC QoS
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QoS Terminology

This section defines some QoS terminology:
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The PFC does not provide QoS for FlexWAN module ports. Refer to the following publications for
information about FlexWAN module QoS features:
– Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.1:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/qos_c/index.htm
Cisco IOS Quality of Service Solutions Command Reference, Release 12.1:
–
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/qos_r/index.htm
Class-Based Marking:
–
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/cbpmark2.
htm
Traffic Policing:
–
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dtpoli.htm
Distributed Class-Based Weighted Fair Queueing and Distributed Weighted Random Early
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Detection:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dtcbwred.
htm
Distributed Low Latency Queueing:
–
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dtllqv
ip.htm
Configuring Burst Size in Low Latency Queueing:
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http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t3/dtcfg
bst.htm
Distributed Traffic Shaping:
–
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121newft/121t/121t5/dtdts.htm
MPLS QoS:
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http://www.cisco.com/univercd/cc/td/doc/product/core/cis7600/cfgnotes/osm_inst/mpls.htm
Packets carry traffic at Layer 3.
Frames carry traffic at Layer 2. Layer 2 frames carry Layer 3 packets.
Labels are prioritization values carried in Layer 3 packets and Layer 2 frames:
Layer 2 class of service (CoS) values, which range between zero for low priority and seven for
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high priority:
Layer 2 Inter-Switch Link (ISL) frame headers have a 1-byte User field that carries an IEEE
802.1p CoS value in the three least significant bits.
Layer 2 802.1Q frame headers have a 2-byte Tag Control Information field that carries the CoS
value in the three most significant bits, which are called the User Priority bits.
Other frame types cannot carry Layer 2 CoS values.
Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
Understanding How PFC QoS Works
31-3