ii
Configuring a QoS policy ········································································································································· 29
QoS policy overview ····················································································································································· 29
Traffic classification overview ······································································································································· 29
Traffic classification ··············································································································································· 29
Packet precedences ··············································································································································· 30
QoS policy configuration procedure ··························································································································· 32
Defining a class ····················································································································································· 32
Defining a traffic behavior ··································································································································· 33
Defining a policy ··················································································································································· 34
Applying the QoS policy ······································································································································ 35
QoS policy configuration example ······························································································································ 36
Displaying and maintaining QoS policies ·················································································································· 37
Configuring hardware congestion management ····································································································· 38
Congestion management overview ······························································································································ 38
Causes, impacts, and countermeasures of congestion ······················································································ 38
Congestion management policies ······················································································································· 38
Weighted fair queuing ········································································································································· 39
CBQ ········································································································································································ 40
Configuring WFQ queuing ··········································································································································· 40
Configuration procedure ······································································································································ 40
Configuration example ········································································································································· 41
Configuring CBQ ··························································································································································· 41
Defining a class ····················································································································································· 41
Defining a traffic behavior ··································································································································· 42
Defining a QoS policy ·········································································································································· 43
Applying the QoS policy ······································································································································ 43
Displaying and maintaining CBQ ······················································································································· 44
CBQ configuration example ································································································································ 44
Configuring priority mapping ··································································································································· 48
Priority mapping overview ············································································································································ 48
Configuring a priority mapping table ·························································································································· 49
Configuration prerequisites ·································································································································· 49
Configuration procedure ······································································································································ 49
Configuration example ········································································································································· 50
Changing the port priority of a port ···························································································································· 51
Configuration prerequisites ·································································································································· 51
Configuration procedure ······································································································································ 51
Configuration example ········································································································································· 51
Configuring the port to trust packet priority for priority mapping ············································································ 52
Configuration procedure ······································································································································ 52
Configuration example ········································································································································· 52
Displaying and maintaining priority mapping ············································································································ 52
Priority mapping configuration example ····················································································································· 53
Configuring congestion avoidance ··························································································································· 55
Congestion avoidance overview ·································································································································· 55
Introduction to WRED configuration ···························································································································· 56
Configuration methods ········································································································································· 56
Introduction to wred parameters ·························································································································· 56
Configuring and applying a WRED table on an interface ························································································ 57
Configuring and applying a queue-based wred table ······················································································ 57
Displaying and maintaining WRED ····························································································································· 57
WRED configuration example ······································································································································ 58
