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Downstream QoS: Ethernet Switch
The simplest way of handling downstream QoS (from WAN to LAN) is to use the per-port queues that are
present in the Ethernet switch. This achieves the greatest efficiency since the queues are handled in the switch
hardware, and should be used when a strict priority queue with 4 priorities is sufficient.
The traffic is classified by priority-bit value. This can be the value retained from WAN ingress (assuming WAN is
tagged,) or it can be a value that is set via a filter rule, which allows for advanced classification criteria to be
used. Even though the LAN interface might not be tagged, there is still an internal priority field which is used to
convey this information to the switch.
Downstream QoS: Egress queues
The secondary method of downstream QoS is to assign egress queues to the LAN port configuration. This is less
efficient, however it allows more advanced queue scheduling algorithms to be used. Packets are classified by
QoS markers set by filter rules.
NOTE:
This method is typically not recommended for deployment configuration as this mechanism can
consume a large amount of CPU processing bandwidth.
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