QoS

QoS (Quality of Service) configuration enables traffic classification, marking, policing, and queuing on NX-OS devices to prioritize critical applications and ensure predictable network performance. It provides a hierarchical policy framework with class maps for DSCP-based traffic classification, policy maps for marking and policing actions with configurable CIR/PIR rates and burst sizes, and queuing policy maps for egress queue scheduling with bandwidth allocation and priority levels. QoS supports system-wide output queuing policy assignment with optional per-policy statistics collection for monitoring traffic treatment across the device.

Diagram

Classes

configuration (nxos.devices)

Name	Type	Constraint	Mandatory	Default Value
qos	Class	`[qos]`	No

qos (nxos.devices.configuration)

Name	Type	Constraint	Mandatory
class_maps	List	`[class_maps]`	No
policy_maps	List	`[policy_maps]`	No
queuing_policy_maps	List	`[queuing_policy_maps]`	No
system_service_policy_queuing_output	String		No
system_service_policy_queuing_output_statistics	Boolean	`true`, `false`	No

class_maps (nxos.devices.configuration.qos)

Name	Type	Constraint	Mandatory
name	String		Yes
match_type	Choice	`match-any`, `match-all`, `match-first`	No
match_dscp_values	List	String	No

policy_maps (nxos.devices.configuration.qos)

Name	Type	Constraint	Mandatory
name	String		Yes
match_type	Choice	`match-any`, `match-all`, `match-first`	No
classes	List	`[classes]`	No

queuing_policy_maps (nxos.devices.configuration.qos)

Name	Type	Constraint	Mandatory
name	String		Yes
match_type	Choice	`match-any`, `match-all`, `match-first`	No
classes	List	`[classes]`	No

classes (nxos.devices.configuration.qos.policy_maps)

Name	Type	Constraint	Mandatory
name	String		Yes
set_qos_group	Integer	min: `0`, max: `7`	No
police	Class	`[police]`	No

classes (nxos.devices.configuration.qos.queuing_policy_maps)

Name	Type	Constraint	Mandatory
name	String		Yes
next_class_map	String		No
previous_class_map	String		No
priority_level	Integer	min: `1`, max: `8`	No
bandwidth_remaining_percent	Integer	min: `0`, max: `100`	No

police (nxos.devices.configuration.qos.policy_maps.classes)

Name	Type	Constraint	Mandatory
cir_rate	Integer	min: `0`, max: `100000000000`	Yes
cir_unit	Choice	`unspecified`, `bps`, `kbps`, `mbps`, `gbps`, `pps`, `pct`	No
bc_rate	Integer	min: `0`, max: `536870912`	No
bc_unit	Choice	`unspecified`, `bytes`, `kbytes`, `mbytes`, `ms`, `us`, `packets`	No
pir_rate	Integer	min: `0`, max: `100000000000`	No
pir_unit	Choice	`unspecified`, `bps`, `kbps`, `mbps`, `gbps`, `pps`, `pct`	No
be_rate	Integer	min: `0`, max: `536870912`	No
be_unit	Choice	`unspecified`, `bytes`, `kbytes`, `mbytes`, `ms`, `us`, `packets`	No
conform_action	Choice	`unspecified`, `transmit`, `drop`, `set-cos-transmit`, `set-dscp-transmit`, `set-prec-transmit`, `set-qos-transmit`	No
conform_set_cos	Integer	min: `0`, max: `7`	No
conform_set_dscp	Any	Integer[min: `0`, max: `63`] or Choice[`default`, `ef`, `af11`, `af12`, `af13`, `af21`, `af22`, `af23`, `af31`, `af32`, `af33`, `af41`, `af42`, `af43`, `cs1`, `cs2`, `cs3`, `cs4`, `cs5`, `cs6`, `cs7`] or String[Regex: `^.[\$\%]\{.$`]	No
conform_set_precedence	Choice	`routine`, `priority`, `immediate`, `flash`, `flash-override`, `critical`, `internet`, `network`	No
conform_set_qos_group	Integer	min: `0`, max: `7`	No
exceed_action	Choice	`unspecified`, `transmit`, `drop`, `set-cos-transmit`, `set-dscp-transmit`, `set-prec-transmit`, `set-qos-transmit`	No
exceed_set_cos	Integer	min: `0`, max: `7`	No
exceed_set_dscp	Any	Integer[min: `0`, max: `63`] or Choice[`default`, `ef`, `af11`, `af12`, `af13`, `af21`, `af22`, `af23`, `af31`, `af32`, `af33`, `af41`, `af42`, `af43`, `cs1`, `cs2`, `cs3`, `cs4`, `cs5`, `cs6`, `cs7`] or String[Regex: `^.[\$\%]\{.$`]	No
exceed_set_precedence	Choice	`routine`, `priority`, `immediate`, `flash`, `flash-override`, `critical`, `internet`, `network`	No
exceed_set_qos_group	Integer	min: `0`, max: `7`	No
violate_action	Choice	`unspecified`, `transmit`, `drop`, `set-cos-transmit`, `set-dscp-transmit`, `set-prec-transmit`, `set-qos-transmit`	No
violate_set_cos	Integer	min: `0`, max: `7`	No
violate_set_dscp	Any	Integer[min: `0`, max: `63`] or Choice[`default`, `ef`, `af11`, `af12`, `af13`, `af21`, `af22`, `af23`, `af31`, `af32`, `af33`, `af41`, `af42`, `af43`, `cs1`, `cs2`, `cs3`, `cs4`, `cs5`, `cs6`, `cs7`] or String[Regex: `^.[\$\%]\{.$`]	No
violate_set_precedence	Choice	`routine`, `priority`, `immediate`, `flash`, `flash-override`, `critical`, `internet`, `network`	No
violate_set_qos_group	Integer	min: `0`, max: `7`	No

Examples

Example 1: Class maps for DSCP-based traffic classification in a data center fabric

nxos:
  devices:
    - name: LEAF1
      configuration:
        qos:
          class_maps:
            - name: CM-VOICE
              match_type: match-any
              match_dscp_values:
                - ef
            - name: CM-CRITICAL-DATA
              match_type: match-any
              match_dscp_values:
                - af31
                - af32
            - name: CM-NETWORK-CONTROL
              match_type: match-any
              match_dscp_values:
                - cs6
                - cs7

Example 2: Policy map with QoS group marking and policing for ingress classification

nxos:
  devices:
    - name: LEAF1
      configuration:
        qos:
          class_maps:
            - name: CM-VOICE
              match_type: match-any
              match_dscp_values:
                - ef
            - name: CM-CRITICAL-DATA
              match_type: match-any
              match_dscp_values:
                - af31
          policy_maps:
            - name: PM-FABRIC-INGRESS
              match_type: match-first
              classes:
                - name: CM-VOICE
                  set_qos_group: 1
                - name: CM-CRITICAL-DATA
                  set_qos_group: 2
                  police:
                    cir_rate: 500
                    cir_unit: mbps
                    bc_rate: 250
                    bc_unit: kbytes
                    conform_action: transmit
                    exceed_action: set-dscp-transmit
                    exceed_set_dscp: 0

Example 3: Full QoS configuration with class maps, policy maps, queuing, and system policy

nxos:
  devices:
    - name: SPINE1
      configuration:
        qos:
          system_service_policy_queuing_output: QM-FABRIC-EGRESS
          system_service_policy_queuing_output_statistics: true
          class_maps:
            - name: CM-VOICE
              match_type: match-any
              match_dscp_values:
                - ef
            - name: CM-SIGNALING
              match_type: match-any
              match_dscp_values:
                - cs3
                - af31
            - name: CM-NETWORK-CONTROL
              match_type: match-any
              match_dscp_values:
                - cs6
                - cs7
          policy_maps:
            - name: PM-SPINE-INGRESS
              match_type: match-first
              classes:
                - name: CM-VOICE
                  set_qos_group: 1
                - name: CM-SIGNALING
                  set_qos_group: 2
                  police:
                    cir_rate: 1
                    cir_unit: gbps
                    pir_rate: 2
                    pir_unit: gbps
                    conform_action: transmit
                    exceed_action: set-dscp-transmit
                    exceed_set_dscp: 0
                    violate_action: drop
                - name: CM-NETWORK-CONTROL
                  set_qos_group: 7
          queuing_policy_maps:
            - name: QM-FABRIC-EGRESS
              match_type: match-first
              classes:
                - name: c-out-q1
                  priority_level: 1
                - name: c-out-q2
                  bandwidth_remaining_percent: 30
                - name: c-out-q-default
                  bandwidth_remaining_percent: 70