Configuring QoS

  1. Configure how local priority values are assigned to ingress packets with the commands qos cos-map, qos dscp-map, and qos trust.
  2. If you do not want to use the default QoS profile to define priority values for ingress traffic, create one or more custom queue profiles with the command qos queue-profile. For each queue in a custom queue profile:
    1. Define a priority value with the command map queue.
    2. Optionally, define a descriptive name with the command name queue.
  3. If you do not want to use the default QoS schedule profile to determine the order in which queues are selected to transmit a packet, create one or more custom schedule profiles with the command qos schedule-profile. For each queue in the custom schedule queue profile, define scheduling priority with the commands strict queue and dwrr queue.
  4. Activate QoS settings with the command apply qos. This command lets you apply a queue profile and schedule profile globally to all interfaces, or a schedule profile override to individual interfaces.
  5. Optionally, add a rate limit for ingress traffic on one or more interfaces with the command rate-limit.
  6. View QoS configuration settings with the commands show interface, show qos cos-map,, show qos dscp-map, show qos queue-profile, qos schedule-profile, and show qos trust.


This example creates the following configuration:

  • Configures CoS to be used to assign local priority to ingress packets.
  • Modifies the default CoS map settings to assign CoS 1 to local priority 1.

  • Creates a queue profile named Q1.
  • Assigns local priority 1 to queue 2.

  • Creates a schedule profile named S1.

  • Assigns DWRR with weight 17 to queue 2.

  • Applies Q1 and S1 as the global default for all interfaces.

switch(config)# qos trust cos
switch(config)# qos cos-map 1 local-priority 1
switch(config)# qos queue-profile Q1
switch(config)# map queue 2 local-priority 1
switch(config)# qos schedule-profile S1
switch(config)# dwrr queue 2 weight 17
switch(config)# apply qos queue-profile Q1 schedule-profile S1