Using multiple global criteria
HPE recommends that you configure a minimum number of global QoS classifiers to prioritize a specific packet type. Increasing the number of enabled global QoS classifiers increases the complexity of possible outcomes and consumes switch resources.
The switches covered in this guide provide six types of globally-configured QoS classifiers (match criteria) to select packets for QoS traffic marking.
When multiple, global QoS classifiers are configured, a switch uses the highest-to-lowest search order shown in the following table to identify the highest-precedence classifier to apply to any given packet. When a match between a packet and a classifier is found, the switch applies the QoS policy configured for the classifier and the packet is handled accordingly.
Search order |
Precedence |
Global QoS classifier |
|---|---|---|
1 |
1 (highest) |
UDP/TCP application type (port) |
2 |
2 |
Device priority (destination or source IP address) |
3 |
3 |
IP type of service: precedence and DSCP bit sets (IP packets only) |
4 |
4 |
IP protocol (IP, IPX, ARP, AppleTalk, SNA, and NetBeui) |
5 |
5 |
VLAN ID |
6 |
6 |
Incoming source-port on the switch |
Default |
7 (lowest) |
The incoming 802.1p priority (present in tagged VLAN environments) is preserved if no global QoS classifier with a higher precedence matches. |
On the switches covered in this guide, if the switch is configured with multiple global classifiers that match the same packet, the switch only applies the QoS marking configured for the QoS classifier with the highest precedence. In this case, the QoS configuration for another, lower-precedence classifier that matches is ignored.
For example, if QoS assigns a high priority to packets belonging to VLAN 100 and normal priority to all IP protocol packets, because the IP protocol priority (4) has precedence over the VLAN priority (5), IP protocol packets on VLAN 100 are set to normal priority.