CANOGA PERKINS 9145EMP NID Software Version 4.0 - Manual (Page 122)

CoS Configuration 9145EMP NID Software User’s Manual
Queues on the 9145EMP
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Chapter 10
CoS Configuration
10.0 Class of Service
CAUTION: When CoS Support settings are set to Enabled, disabling may lead to tempo-
rary packet loss and/or packet mis-ordering.
When throughput exceeds the available bandwidth, Class of Service (CoS) mechanisms allow
the 9145EMP to selectively drop service frames based on priority of the packets serviced. CoS
processing occurs on the egress direction, that is, for frames leaving the NID.
From the Class of Service Configuration screen (Figure 10-2), you can enable or disable CoS
support, including Classification, Queuing, Scheduling, and Queue Management functions.
10.1 Queues on the 9145EMP
Each User port has an independent set of four queues (Figure 10-1). The queues are labelled
from highest to lowest priority:
• LLQ (Low Latency Queue)
• Q3
• Q2
• Q1
There is a single set of configuration attributes for the queues on the user side, even if the
queues are independent per port. The same configuration parameters apply to all queue sets
across all the ports.
On the network side, 16 queues are available, statically assigned to each ingress user port in
groups of four. The first four queues are assigned for frames received on USR1, the next four for
frames received on USR2, and so forth. For this reason, the screens for the network port refer
only to four queues labelled LLQ to Q1; read this label as Q1 through Q4 for the queue set of the
corresponding ingress user port.