Quality of Service (QoS): Managing Bandwidth More Effectively  
Contents 
QoS IP Type-of-Service (ToS) Policy and Priority  . . . . . . . . . . . . . . . 6-34  
Assigning an 802.1p Priority to IPv4 Packets on the Basis of the ToS   
Assigning an 802.1p Priority to IPv4 Packets on the Basis of Incoming   
Assigning a DSCP Policy on the Basis of the DSCP in IPv4 Packets   
Precedence Bits  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35  
DSCP  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36  
Received from Upstream Devices  . . . . . . . . . . . . . . . . . . . . . . . . .  6-40  
Details of QoS IP Type-of-Service  . . . . . . . . . . . . . . . . . . . . . . . . .  6-43  
QoS VLAN-ID (VID) Priority  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-46  
Assigning a Priority Based on VLAN-ID  . . . . . . . . . . . . . . . . . . . . 6-46  
Assigning a DSCP Policy Based on VLAN-ID (VID) . . . . . . . . . . .  6-48  
QoS Source-Port Priority  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6-52  
Assigning a Priority Based on Source-Port . . . . . . . . . . . . . . . . . . 6-52  
Assigning a DSCP Policy Based on the Source-Port  . . . . . . . . . .  6-54  
Steps for Creating a Policy Based on Source-Port Classifiers  . .  6-54  
Differentiated Services Codepoint (DSCP) Mapping  . . . . . . . . . . . . .  6-58  
Default Priority Settings for Selected Codepoints . . . . . . . . . . . .  6-59  
Quickly Listing Non-Default Codepoint Settings  . . . . . . . . . . . . .  6-60  
Effect of “No-override”  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-61  
Note On Changing a Priority Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-62  
Example of Changing the Priority Setting on a Policy When One or   
More Classifiers Are Currently Using the Policy  . . . . . . . . . . . . .  6-62  
IP Multicast (IGMP) Interaction with QoS  . . . . . . . . . . . . . . . . . . . . . . . . .  6-65  
QoS Messages in the CLI  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-65  
QoS Operating Notes and Restrictions  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6-66  
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