Configuration > Quality of Service

VLAN Priority (Precedence 5)

The QoS VLAN Priority lets you assign a priority to outbound packets containing the specified VLAN-ID (VID). Packets containing the specified VID are marked with the priority level configured for the VID classifier. This 802.1 priority determines the outbound port queue to which the packet is sent. If the packet leaves the switch in a tagged VLAN, it carries the 802.1p priority with it to the next downstream device.

For example, if the default VLAN (VID 1) and the Blue VLAN (VID 20) are both assigned to a port, and Blue VLAN traffic is more important, you can configure QoS to give Blue VLAN traffic a higher priority than default VLAN traffic.

Up to 256 (400 for software release E.08.01 or greater) VID QoS classifiers can be created for static VLANs. (You cannot use QoS for dynamic VLANs created by GVRP.) Eliminating a VID from the switch causes the switch to clear any QoS features configured for that VID.

For operation when other QoS classifiers apply to the same traffic, refer to Precedence Criteria.

To assign a priority to a VLAN-ID:

  1.  Configure the DSCP Policy you want to assign to the VLAN-ID.

  2. A DSCP policy must be created before you can configure the codepoint to prioritize packets based on VLAN-ID. If a codepoint shows No-override in the Priority column of the DSCP Policy Table, you must assign a priority (0 -7) before proceeding.

  1. Select Quality of Service from the Configuration tab, and then select VLAN Priority from the left pane. The VLAN Priority window lists all VLANs configured in the network.

  2. From the list, select the VLAN to which you want to assign a priority.

  3. Click the DSCP Policy drop-down arrow and select the DSCP policy you want to use for the VLAN. The DSCP policy identifies the 802.1 priority and the codepoint used to overwrite the DSCP carried in packets received from upstream devices.

  4. Select the priority you want to associate with the VLAN-ID. Possible values are 0-7 and No Override, which does not prioritize the packet unless another QoS policy creates priority assignments.

If a priority is not assigned, IP packets received through a VLAN-tagged port receive whatever 802.1p priority they carry in the 802.1Q tag in the packetís header. VLAN-tagged packets received through an untagged port are handled in the switch with normal priority.

  1. Click Modify.

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