CDM-570A/570AL Satellite Modem with Optional Packet Processor
Revision 5
Advanced Quality of Service (QoS) Option L–10 MN-CDM570A
QUESTION: What is the total output data rate and what are the individual port output data rates?
ANSWER:
• The QoS system first drains Priority 1 traffic. Since the management data stream is only
200 Kbps, after serving Priority 1 traffic, QoS still has 9.8 Mbps (10.0-0.2=9.8).
•
QoS next drains Priority 2’s 800 Kbps traffic. After the end of the Priority 2 traffic, QoS
still has 9 Mbps traffic available (9.8-0.8=9).
•
Similarly, QoS walks through all priorities until it hits the ASFD classes:
o
The beginning of ASFD Classes QoS leftover bandwidth is 2 Mbps.
o
All ASFD classes have the same Priority of 7, with different service rates.
o
ASFD service rate is a Committed Information Rate (CIR), except serviced if
bandwidth available after serving all high priority queues. In this case, 2 Mbps
bandwidth is available, serving all service rates first. The total of all ASFD service
rates are 1.6 Mbps, which is less than the 2 Mbps leftover bandwidth.
o
After serving the service rates, the leftover bandwidth is 400 Kbps. This 400 Kbps will
be distributed to all ASFD classes equally in round robin fashion until either there is
no more bandwidth, or the input streams have no data.
The resulting individual data rates are as follows:
Stream Priority PHB / DSCP Code Service Rate
Data Rate
Networking Control 2 CS6 / b110000 800 Kbps 9.0 Mbps 800 Kbps
Data-1 4 CS4 / b100000 550 Kbps 3450 Kbps 550 Kbps
Data-3 7 ASFD4 / b100010 1 Mbps NA 100 + 100 Kbps
Data-4 7 ASFD3 / b011010 1 Mbps NA 400 + 100 Kbps
Data-6 7 ASFD1 / b001010 1 Mbps NA 800 + 100 Kbps
Data-7 8 BE / bXXXXXX 2 Mbps NA 0 Kbps
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