QoS operation

On the switches covered in this guide, QoS operation may be configured through a combination of the following methods:

  • Globally-configured, switch-wide QoS settings

  • Classifier-based per-port and per-VLAN QoS policies.

Classifier-based QoS policies are designed to work with existing globally-configured, switch-wide QoS settings by allowing you to zoom in on a subset of port or VLAN traffic to further manage it. You can use multiple match criteria to more finely select and define the classes of traffic that you want to manage. QoS policy actions determine how you can handle the selected traffic.

[NOTE: ]

NOTE: Carefully plan your QoS strategies in advance, identifying the network traffic that you can globally configure and the traffic on which you want to execute customized, classifier-based QoS actions.

Globally-configured QoS

Globally-configured QoS operation supports the following types of packet classification and traffic marking on outbound port and VLAN traffic.

  • Globally configured packet classification criteria include:

    • IPv4 device: source and destination address

    • Layer 2 802.1p priority (VLAN header)

    • Layer 3 protocol (such as ARP, IP, IPX, RIP)

    • Layer 3 IPv4 Type of Service (ToS) byte: IP precedence or DSCP bits

    • Layer 4 UDP/TCP application port

    • Source port on the switch

    • VLAN ID

  • Traffic marking options are as follows:

    • Setting the Layer 2 802.1p priority value in VLAN-tagged and untagged packet headers

    • Setting the Layer 3 Differentiated Services Codepoint (DSCP) bits in the ToS byte of IPv4 packet headers and Traffic Class byte of IPv6 headers.