Comtech EF Data CDM-570A - Manual (Page 573)

CDM-570A/570AL Satellite Modem with Optional Packet Processor MN-CDM570A
Appendix L Revision 2
L–13
QUESTION: What will be the total data rate and what will be the individual data rates?
ANSWER :
• After serving all high priority queues, only 500 Kbps is left for ASFD classes.
• This leftover bandwidth is less than the total minimum bandwidth; it must therefore share
the residual 500 Kbps among all four ASFD classes equally - i.e., 500/4=175 Kbps per class.
• Since ASFD 4 has the service rate 100 Kbps, the excess 75 Kbps will be given the other
queues where the service rate not met.
• In this case the 75 Kbps again will share equally among ASFD3, ASFD2, and ASFD1 since
these service rates were not met.
• The resulting individual data rate is as follows:
Stream Priority
PHB / DSCP
Code
Input Data rate
Leftover BW (After
Serving the Queue)
QoS output Data rate
Management 1 CS7 / b111000 200 Kbps 9.8 Mbps 200 Kbps
Networking Control 2 CS6 / b110000 800 Kbps 9.0 Mbps 800 Kbps
Voice 3 EXFD / b101110 1 Mbps 8.0 Mbps 1Mbps
Video 3 CS5 / b101000 4 Mbps 4.0 Mbps 4 Mbps
Data-1 4 CS4 / b100000 550 Kbps 3450 Kbps 550 Kbps
Data-2 5 CS3 / b011000 1450 2000 Kbps 1450 Kbps
Data-3 7 ASFD4 / b100010 1 Mbps NA 100 Kbps
Data-4 7 ASFD3 / b011010 1 Mbps NA 175 + 25 Kbps
Data-5 7 ASFD2 / b010010 1 Mbps NA 175 + 25 Kbps
Data-6 7 ASFD1 / b001010 1 Mbps NA 175 + 25 Kbps
Data-7 8 BE / bXXXXXX 2 Mbps NA 0 Kbps
TOTAL N/A N/A 14 Mbps 0 Kbps 8.7 Mbps
L.3 Glossary of Terms
Filtering – QoS allows specific flows to be designated as “filtered,” whereby the IP Packet
Processor discards traffic that is otherwise not wanted for forwarding over a satellite link.
Jitter – Measured in milliseconds, this is the amount of variation between two consequent
frames at the receiving end.
Latency – This is the amount of delay, measured in milliseconds, from Ethernet interface of the
near -end modem to the Ethernet interface of the far-end modem.
Maximum Bandwidth – This value can be assigned to a flow to restrict the Maximum Bandwidth
that any particular flow will utilize; otherwise, the default of no bandwidth restriction can be
selected.