Filter
Top Products
ADC Telecommunications, Inc.
412 C
HAPTER 18: CONFIGURING CABLE MODEM TERMINATION SYSTEMS
Understanding Frequency Hopping Parameters
Frequency Hopping parameters are set within interface:cable:csi <c/s/i>
mode.
For each upstream channel you can configure up to five policies. Each of
these policies consists of the following four parameters:
Table 18-3 Frequency Hopping Parameters
When the error threshold is reached over the configurable time, the
upstream frequency and burst profile is changed to those specified in the
profile. This allows you to have considerable control and flexibility. For
example, when upstream spectrum for a channel degrades, the initial policy
specified may be to keep the tuned center frequency the same and increase
FEC, or change from 16 QAM to QPSK in an attempt to improve the use of
the spectrum. If the change in operating parameters based on the first policy
fails to meet the configured error threshold, then the next policy may be to
change to another center frequency in an attempt to find another channel
with acceptable quality. Each of these policies is attempted in a round-robin
fashion to maintain upstream quality.
Parameter Description
Threshold The percentage error threshold for this
frequency hopping policy entry.
Interval The threshold interval for this frequency
hopping policy entry in seconds.
Profile The upstream burst profile number to be used
when error threshold is reached in configured
threshold interval time.
Frequency (MHz) The center frequency value to be used when
error threshold is reached in configured
threshold interval time