Xerox NS-2260 - Manual (Page 22)

1.5.9 QoS Priority Function
This switch supports two priority levels, high and low, and provides two priority functions:
1. Port-based Priority (Static priority)
2. 802.1p Priority (VLAN tagged priority)
Priority Classification Methods
Static priority is called port -based priority. The priority level of a receiving packet is determined by the
configured priority of the input port where the packet is received and the content of the packet is ignored.
Each port must be pre-configured with a priority level for incoming frames or disabled setting.
802.1p Priority is a content-based priority method. If the receiving packet is an 802.1Q VLAN tagged
packet, the switch will check the 3 -bit User Priority value in TCI (Tag Control Information) field of packet
tag data. By this value, the packet is classified as high priority or low priority according to 802.1p priority
configuration. The map of priority values vs. priority levels must be pre-configured.
The switch uses the following rules:
1. Applies Static Priority method first for tagged or untagged packets.
2. If port static priority is disabled, applies 802.1p Priority method.
3. Untagged packets are treated as low priority.
Outgoing Service Policy
The switch provides two options for outgoing service policy for high priority packets and low priority
packets.
1. High priority always first
2. Round robin method with specified [High : Low] ratio setting
This policy configuration can be set via the management interface.