Classifier-based QoS model

Classifier-based QoS configuration consists of the following general steps:

  1. Classify the traffic that you want to manage by configuring a class.
  2. Configure a QoS policy in which you specify the QoS actions to execute on each class of traffic.
  3. Assign the QoS policy to a port or VLAN (inbound only) interface.


Classifier-based QoS operation supports all globally-configured packet classification criteria (except for Source-port and Layer-3 protocol) and traffic marking functions, and provides additional QoS actions on a per-port and per-VLAN basis.

  • Classifier-based match criteria on inbound IPv4/IPv6 traffic include:
    • IP source address (IPv4 and IPv6)

    • IP destination address (IPv4 and IPv6)

    • IP protocol (such as ICMP or SNMP)

    • Layer 3 IP precedence bits

    • Layer 3 DSCP codepoint

    • Layer 4 TCP/UDP application port (including TCP flags)

    • VLAN ID

  • Classifier-based QoS policy actions on matching IPv4/IPv6 packets are as follows:
    • Setting the Layer 2 802.1p priority value (class of service) in VLAN-tagged and untagged packet headers

    • Setting the Layer 3 IP precedence bits

    • Setting the Layer 3 Differentiated Services Codepoint (DSCP) bits

    • Rate limiting inbound traffic on port and VLAN interfaces