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Cirius LM User Manual 2016 Page 65
port also plays a role in determining what configurable rate limits are available to
that ingress port. (See the Port Based Rate Limiting section below.)
The IDU’s Ethernet Switch includes four separate output queues for each egress
port, one for each definable priority level. The IDU allows the selection of one of
two scheduling modes, a strict priority scheme or a fair weighted priority scheme,
which determines how the frames are allowed to exit from the given output port.
When the strict priority scheme is selected for the port, all top priority frames are
egressed from the port before the next lower priority frames are egressed, and so
on. When the fair weighted queuing scheme is selected for the port, an 8,4,2,1
weighting is applied to the four priorities.
Note that the Priority Queuing feature is independent of any VLAN function, and
ignores the contents of the VLAN tag if frames ingress with VLAN tags. For each
port (excluding the modem port), the parameters listed in Table 13 are
independently configurable.
Parameter Name Allowed Values
Port-Based Priority Disabled
Enabled
Port Priority, selectable for
each front panel port
0, 1, 2 or 3
(3 being highest priority)
Priority Scheme
(Scheduling Mode)
Fair-Weighted: Use an 8,4,2,1 fair weighted
queuing scheme
Strict: Use a strict priority scheme
Table 13 Port-based QoS Priority Configuration Parameters for Each Port
4.3. Port Based Rate Limiting
The platform also provides a configurable port-based ingress rate limiting feature.
Ingress rates for each port can be independently set to any of the limits listed in
Table 14. Note that settable rate limits are a function of the QoS Priority assigned
to the port (see Port Based QoS Priority section above):