Details of packet criteria and restrictions for QoS support
| Packet criteria or restriction | QoS Classifiers | DSCP overwrite (re-marking) | ||||||
|---|---|---|---|---|---|---|---|---|
| UDP/TCP | Device priority (IP address) | IP ToS | Layer 3 Protocol | VLAN | Source port | Incoming 802.1p | ||
| Restricted to IPv4 packets only | Yes | Yes | Yes | No | No | No | No | Yes |
| Allow packets with IP options[a] | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No |
| Support IPv6 packets | No | No | No | Yes | Yes | Yes | Yes | No |
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[a] For explicit QoS support of IPv6 packets, force IPv6 traffic into its own set of VLANs and then configure VLAN-based classifiers for those VLANs. |
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All switches: For explicit QoS support of IP subnets, HP recommends forcing IP subnets onto separate VLANs and then configuring VLAN-based classifiers for those VLANs.
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For devices that do not support 802.1Q VLAN-tagged ports: For communication between these devices and the switch, connect the device to a switch port configured as
Untaggedfor the VLAN in which you want the device's traffic to move. -
Port tagging rules: For a port on the switch to be a member of a VLAN, the port must be configured as either
TaggedorUntaggedfor that VLAN. A port can be an untagged member of only one VLAN of a given protocol type. Otherwise, the switch cannot determine which VLAN should receive untagged traffic. -
Maximum QoS configuration entries: The switches covered in this guide accept the maximum outbound priority and/or DSCP policy configuration entries shown in the following table:
Maximum QoS entries
Switch Software version Maximum QoS entries of one type Notes Switch 2920
WB.15.XX 250[a] -
Each device (IP address) QoS configuration uses two entries.
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Each TCP/UDP port QoS configuration uses four entries.
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All other classifier configurations use one entry each.
[a] Configuring device (IP address), TCP/UDP QoS entries, or other entries reduces this maximum. See the “Notes” column.
Attempting to exceed the above limits generates the following message in the CLI:
Unable to add this QoS rule. Maximum number ( entry-#) already reached. -
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Not supported: Use of an inbound 802.1p packet priority as a classifier for remapping a packet's outbound priority to different 802.1p priority. For example, where inbound packets carry an 802.1p priority of 1, QoS cannot be configured use this priority as a classifier for changing the outbound priority to 0.
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Monitoring shared resources: The QoS feature shares internal switch resources with several other features. For information on determining the current resource availability and usage, see “Monitoring Resources” in the Management and Configuration Guide for your switch.