Juniper G10 CMTS, Hardware Manual

Page: 159 / 210

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Troubleshooting
Features for Troubleshooting
143
Table 45: Flap List Association to Potential Issues
Output Field Value Potential Issues
IM (initial maintenance
retry flaps)
High
!
DHCP server issues
!
TFTP server issues
!
Configuration file issues
SM (missed station
maintenance flaps)
High
!
Noise
!
Ingress
!
Impairments such as common path distortion
!
Laser clipping distortion
!
Attenuation (too large or too small)
CER (codeword error rate
flaps)
High (with low CERavg)
!
Impulse noise
CERavg (average CER) High
!
Ingress
!
Impulse noise
!
Impairments such as common path distortion
!
Laser clipping distortion
PAdj (power adjust flaps) High
!
High attenuation in the return path
!
Changing environmental conditions that affect the
return path such as temperature
!
Improper amplification
!
Poor amplifier performance
FAdj (frequency adjust
flaps)
High
!
Significant frequency error introduced by frequency
stacking multiplexer (sometimes called
block
upconversion ) in the return path
!
Degraded frequency stability in cable modem
SNRavg (SNR average) Low
!
Increase in return path noise due to:
!
Amplifier thermal noise
!
Fiberoptic link noise
!
Ingress noise
!
High attenuation in the return path
MERavg (MER average) Low Any issues that affect the phase and amplitude of the
signal in the return path:
!
Noise
!
Impairments
!
Non-linear distortions (in lasers and amplifiers, for
example)
!
Linear distortions such as group delay variance
!
Quality of cable modem transmitter