Chapter 21: Integrated Upstream Agility
STANDARD Revision 1.0 C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved. 666
configure cable spectrum-group 5 sample-period 10
configure cable spectrum-group 5 min-codewords 1000
configure cable spectrum-group 5 hop-period 10
configure cable spectrum-group 5 retry-period 10
configure cable spectrum-group 5 state 1 freq 20000000 width 3200000 modulation-profile 1100
configure cable spectrum-group 5 state 2 freq 28000000 width 3200000 modulation-profile 1100
configure cable spectrum-group 5 state 3 freq 20000000 width 1600000 modulation-profile 1100
configure cable spectrum-group 5 state 4 freq 28000000 width 1600000 modulation-profile 1100
configure cable spectrum-group 5 state 5 freq 20000000 width 3200000 modulation-profile 1000
configure cable spectrum-group 5 state 6 freq 28000000 width 3200000 modulation-profile 1000
configure cable spectrum-group 5 state 1 trigger 10 next-state 2
configure cable spectrum-group 5 state 2 trigger 10 next-state 3
configure cable spectrum-group 5 state 2 trigger 20 next-state 1
configure cable spectrum-group 5 state 3 trigger 10 next-state 4
configure cable spectrum-group 5 state 3 trigger 20 next-state 2
configure cable spectrum-group 5 state 4 trigger 10 next-state 5
configure cable spectrum-group 5 state 4 trigger 20 next-state 3
configure cable spectrum-group 5 state 5 trigger 10 next-state 6
configure cable spectrum-group 5 state 5 trigger 20 next-state 4
configure cable spectrum-group 5 state 6 trigger 20 next-state 5
In the example given above, the MSO has decided to use six of the eight possible states. They are chained together using
degradation triggers and improvement triggers. In this arrangement:
State 1, the default, is the channel configuration with the highest theoretical throughput. It is also very susceptible to
channel noise, which sometimes leads to an unacceptable Packet Error Rate (PER). If that occurs, then the Upstream Agility
state machine transitions from State 1 to State 2.
State 2 has a theoretical throughput identical to that of State 1, but it is positioned in a different portion of the upstream
spectrum. Perhaps the noise source is not present in that part of the spectrum. If hopping to State 2 does not resolve the
problem because it, too, has an unacceptable PER, then a degradation trigger forces the state machine to transition to
State 3.
State 3 has a lower theoretical throughput than States 1 and 2, because its channel width and signal rate are only half as
great as those found in States 1 and 2. However, State 3 is more tolerant of upstream noise, and may be able to provide
adequate PER performance. If not, another degradation trigger forces the state machine to transition from State 3 to State
4.
State 4 has a theoretical throughput identical to that of State 3, but is positioned in a different portion of the upstream
spectrum. If changing to the center frequency given in State 4 does not result in an improved PER performance, then a
degradation trigger forces the Upstream Agility state machine to transition to State 5.
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