cable upstream hopping

[imedina]

Hi,

The default configuration on CMTS is "cable upstream hopping optimized" and it could change manually to "cable upstream hopping blind".

I need to know what it mean "optimized" and to be more specific: how the CMTS select the frequency to work on after he decided to do a frequency hop.

Thanks,

Israel.

[makchitale]

Frequency hopping can be configured in blind, scheduled, or intelligent(optimized) modes. The frequency is selected based on a predefined spectrum group. Scheduled frequency hopping is the simplest form, which hops at a predefined time and frequency. The difference between intelligent versus blind is that blind hopping simply marches down the spectrum group until a satisfactory frequency is found. Intelligent hopping performs look ahead of all frequency bands in the spectrum group, and hops to a clean band.

Frequency hopping decision algorithms are based on the following criteria:

• CNR thresholds

• Modulation switching and channel width switching

• Hopping priority

• FEC (correctable & uncorrectable)

These thresholds are configurable through CLI.

CNR thresholds: It’s per SID and CM based CNR.

Corrected FEC: The number of correctable FEC errors, default value 3% will be applied to all cards.

Uncorrectable FEC: The number of uncorrectable FEC errors, default is 1%.

Thanks, Mak

[imedina]

Hi Mak,

thanks for the helpful answer.

can you pleas point me to a more detailed documentation on the subject.

regurds,

israel.

[makchitale]

I could not find any good CCO document for this, the info that I provided is thru research into our internal engineering documents.

However if I find one will update this posting.

Thanks, Mak