Scout / Scout FLUX Flashcards
A feature in Scout that can help identify drop and mainline problems.
Scout Flux
Provides a view into the upstream uncorrectable error rates for an entire upstream channel.
FEC Dashboard
Analyzes the forward error correction counters and signal-to -noise metrics for the upstream traffic on the entire channel.
FEC microscope
Brings up the last seven days of uncorrectable codeword rates grouped into one-hour polls.
FEC Uncorrectable History
Provides a view into which upstream channel(s) are being used by a particular node.
Upstream Channel Node Lookup
Where you can enter a customer device to be monitored for the online status every 10 minutes.
CM Watch
Where you can find information for a particular customer.
Customer Report
Where you can enter a node and the tool does a real-time check on all the modems in that node looking for service outages or potential degraded service issues.
Node Analyzer
Where you can create a custom report that displays real-time data for a particular device with attributes you select.
Real Time CM
Where you can see the results from the device query performed under the Real Time CM tab.
Batch Results
Provides customer billing information from CPE, the CM and MTA devices provisioned to the customer, the Video STB devices, and VOD streams and errors.
Customer Report
Engineer that led the effort to develop Scout FLUX?
Larry Wolcott
Feature of DOCSIS 2.0, or newer systems in which Digital Signal Processor (DSP) corrects signal echos and impairments.
Adaptive Equalization
3 types of Linear Distortions
Micro-reflections Amplitude tilt (ICFR) Group delay
Two types of upstream distortions
linear
non-linear
Are caused by impedance mismatches and are indicated by a change in the amplitude and phase of a signal for a given frequency point.
Linear distortions
Bouncing back and forth of a signal between two interfaces that have an impedance mismatch.
Micro-reflection
A non-flat frequency response in which the amplitude versus frequency characteristic of the channel or operating spectrum is sloped or tilted across a specific frequency range.
Amplitude tilt
Observed when all portions of the channel do not arrive at the receiver at the same time.
Group delay
common examples of non-linear distortions:
Common Path Distortion (CPD)
Composite Second Order (CSO)
Composite Triple Beat (CTB)
A process in which a DSP actively corrects signal echoes and other linear distortions.
Upstream Pre-equalization
For most cases what is the distance between equalizer taps in the Impulse Coefficients Bar Chart?
85 feet
When not in signature mode what are the modem colors and what do they mean?
Green- OK
Yellow- Minor problem
Red- Major problem
Grey / Black- offline / Does not support adaptive equalization.
Red / Yellow lightening Bolt- Distortion is still present after equalization.
What do the modem colors indicate in signature mode?
Groups of modems with common signatures
What two approaches does FLUX use to approximate the location of a problem?
Time domain
Frequency domain
Which EQ tap is known as the main tap and signifies the cable modem time at zero?
EQ Tap 8
EQ taps to the right of tap 8 are used to?
Compensate for echoes
EQ taps to the left of tap 8 are used to?
Counter group delay and phase
The Coefficients bar chart is accurate to within?
20 feet
Name the four places that Scout Flux data can be accessed
Scout
GrandSlam
Market Health
Watchtower
Scout menu used for logging out or where administrators will go to access administrative features
Admin
Scout menu used For accessing pages related to real-time device data
Device Watch
Scout menu used For accessing the Comcast Digital Voice, or CDV, Call Summary and Upstream Interface Settings
CMTS Tools
Scout menu used For accessing pages related to legacy digital set top box (or STB) video monitoring
Video Monitoring
Scout menu used For finding rollup summary data for Upstream Forward Error Correction (or FEC) rates, video STBs, and Video On Demand, or VOD streams
Dashboards
The path to view upstream uncorrectable error rates for an entire upstream channel in scout
Dashboards -> FEC Errors
DSP
Digital Signal Processor
Provides a view into which upstream channel(s) are being used by a particular node
Upstream Channel Node Lookup
Where you can enter a customer device to be monitored for the online status every 10 minutes - this watch page does not generate any automated alerts though
CM Watch
Where you can find information for a particular customer
Customer Report
Where you can see statistics statistics for Xfinity WiFi
Beacon Report
Where you can enter a node and the tool does a real-time check on all the modems in that node looking for service outages or potential degraded service issues.
Node Analyzer
Where you can create a custom report that displays real-time data for a particular device with the attributes you select
Real Time CM
Where you can see the results from the file upload from the device query performed under the Real Time CM tab
Batch Results
Adaptive Equalization is a feature of this standard
DOCSIS 2.0 or greater.
A type of distortion that is caused by impedance mismatches and are indicated by a change in the amplitude and phase of a signal for a given frequency point
Linear Distortions
ISI
Intersymbol Interference
This type of interference prevents the receiver from detecting the correct amplitude and phase of the received signal
Intersymbol Interference
Three main categories of linear distortions
Micro-reflections
Amplitude Tilt (ICFR)
Group Delay
The bouncing back and forth of a signal between two interfaces that have an impedance mismatch
Micro-Reflections
Most common causes of micro-reflections
Unterminated ports
Bad Connectors
Bad Passives
Damaged Cables
A non-flat frequency response in which the amplitude versus frequency characteristic of the channel or operating spectrum is sloped or tilted across a specified frequency range.
Amplitude Tilt
This is observed when all portions of the channel do not arrive at the receiver at the same time.
Group Delay
Most common cause of Group Delay
The diplex filter or any kind of filtering mechanism
in home amplifiers can also be a factor
Common Examples of non-linear distortions
Common Path Distortions (CPD)
Composite Second Order Distortion (CSO)
Composite Triple Beat Distortion (CTB)
When a DSP actively corrects signal echoes and other linear distortions.
Upstream Pre-Equalization
The continuous, closed-loop feedback process between the modem and the CMTS
Adaptive Equalization
The five graphs in Scout Flux
Impulse Coefficients Bar Chart
In-Channel Frequency Response (ICFR) Graph
Phase Response Graph
Group Delay Graph
Quadrature Amplitude Modulation (QAM) Constellation
This chart graphs equalization coefficients in the time domain
Impulse Coefficients
This can be thought of as time delays created by impairments between the CMTS and the device
EQ Coefficients
One EQ Tap equals approximately how many feet?
85’
This graph is an invers of the actual issue in the field
In Channel Frequency Response (ICFR) Graph
On the ICFR Graph, if the equalized graph looks worse than the Pre-EQ graph the problem lies in one of these two places
At the CMTS or Additive Ingress
Both of these graphs show the non-linear relationship between phase and frequency
Phase Response Graph and Group Delay Graph
Each box represents a unique set of bits called symbols in this graph
QAM Constellation
The edges of the boxes in the QAM Constellation are known as what?
The Decision Boundary
if there is random scattering on the equalized side of the QAM Constellation, what might this indicate?
Presence of Ingress, a Non-Linear Distortion, or a Linear Distortion that is constantly changing
Equalization is intended to correct what type of distortion?
Linear Distortions
A red or yellow lightning bolt indicates what?
Distortion is still present after equalization
In scout Flux these are the parameters that define the signature groups
Match Strength, Ripple dB, FFT (Fast Fourier Transform) Points and Defeat Taps
The Taps to the Left of Tap 8 are used for what?
Compensate for Group Delay and Phase
The Taps to the Right of Tap 8 are used for what?
Compensate for Echoes
When using a meter to troubleshoot issues in FLUX, what type of channel should you be using on your test equipment?
A-TDMA