Plant Reliability

Larry JumpJDSU Field Applications Engineer814 692 [email protected] 866 228 3762 Opt. 3 / 2

Plant Reliability

mailto:[email protected]

© 2011 JDSU. All rights reserved. JDSU CONFIDENTIAL & PROPRIETARY INFORMATION2

Agenda 3 major areas of concern

Coax Fiber Inside plant


Purpose

To provide better service to our customers in light of competition– Maintain plant instead of reacting to problems– Be alerted to issues before the customer notices– Maintain reliability for essential services

To increase revenues

The outside plant


• Less manpower needed

• Sweeping can does reduce the number of service calls

VOD not working

Internet not workingChannel 12 video

problemsCracked hardline found with SWEEP

WHY SWEEP?


WHY SWEEP?

Loose Face Plate

No Termination


Sweep vs. Signal Level Meter Measurements

References: Sweep systems allow a reference to be stored eliminating the effect of headend level error or headend level drift.

Sweep Segments: Referenced sweep makes it possible to divide the HFC plant into network sections and test its performance against individual specifications.

Non-Invasive: Sweep systems can measure in unused frequencies. This is most important during construction and system overbuilding.

BEST Solution to align: Sweep systems are more accurate, faster and easier to interpret than measuring individual carriers.


Frequency Response Definition

System’s ability properly to transmit signals from headend to subscriber and back throughout the designed frequency range

Expected Results (Traditionally): n/10 + x = max flatness variation

• where n = number of amplifiers in cascade• where x = best case flatness figure (supplied by

manufacturer)

Expected Results in current HFC Networks: Typically < 3 to 4 dB max flatness variation anywhere in the network (check with your Manager for max flatness variation limits)


Forward Path Considerations

Diverging System Constant Outputs Channel Plan to Match Fixed

Signals–video / audio / digital carriers

Sweep Telemetry Carriers, 1MHz wide

System Noise– is the sum of cascaded amplifiers

Balance or Align (Sweep)–compensate for losses before the amp


Sweep Reference Considerations

Typically the node is used for the reference

Use test probe designed for node/amp It’s a good engineering practice to store

a new reference each day Establish reference points to simplify

ongoing maintenance (sweep file overlay)

Need to know amps hidden losses in return path (Block diagrams / Schematics)

Need to know where to inject sweep pulses and the recommended injection levels


Unity Gain in the forward path

R

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Each amplifier compensates for the loss in the cable and passives before the amplifier under test. The system is aligned so that the levels at each greenarrow are exactly the same.


Why do we need Unity Gain?

22 22 22 22

32/26 31/25 30/24 29/23

23 23 23

If Unity Gain is not observed distortions and or noise build

up quickly!


Forward Sweep Display

Markers

Max/Min

ReferenceName

dB/div


A Sweep Finds Problems That Signal Level Measurements Miss

Standing Waves

Roll off at band edges

Misalignment


Sweeping Reverse Path Goals

The objective in reverse path alignment is to maintain unity gain with constant inputs and minimize noise and ingress.

Set all optical receivers in the headend to same output level and ideally the same noise floor to optimize C/N ratio.– The reverse path noise is the summation of all

noise from all the amplifiers in the reverse path.

Adjust sweep response to match 0dB flat line Sweep reference and 0dBmV Telemetry level


Before reverse sweeping begins….

Optimize the upstream node Splitting, combining and padding considerations in

the headend.


Return Optics We discuss this first because it has the greater impact on

the MER at the CMTS input because it has the lowest dynamic range

Optimized by measuring NPR at the input to the CMTS by injecting different total power at the input to laser.

Carriers should be derated according to bandwidth using power per hertz.

Not part of the unity gain portion of the HFC plant. Set up is laser and node specific


NPR Measurement Measured by injecting a wideband noise source with a notch filter at

the input. Then measuring essentially the noise to the notch at the output.

Measured as 10 log Power/hz of the signal/Power/hz of the notch noise

The lower the signal the lower the CNR, the higher the signal, the more distortion.

Input starts low and then raised in 1 dB steps


Power per Hertz Calculation

Power per Hertz dBmV/Hz = Total Power – 10 Log (BW) dBmV/HZ = 45 – 10 Log (37,000,000) dBmV/ Hz = 45 – 10 (7.57) dBmV/ Hz = 45 – 75.7 dBmV/ Hz = -29.3

Total Power Input for 6.4 MHz 64 QAM

dBmV = -29.3 + 10 Log (BW)dBmV = -29.3 + 10 Log (6,400,000)dBmV = -29.3 + 10 (6.8)dBmV = -29.3 + 68dBmV = 38.7


REVERSE LEVEL

All signal levels must be set to same output level at the optical receiver in the headend or hubsite with the same input at the node.

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System Sweep Transmitter 3SRSystem Sweep Transmitter 3SR Stealth SweepStealth Sweep

System Sweep Receiver Model 3SR

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REVERSE NOISER

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Ideally all combined nodes should have same noise floor to maximize C/N ratio.


Headend combining and splitting

Set top converter

PathTrak

CMTS

Other Return Services

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Return Sweep considerations Instead of point to multipoint, the system is multipoint to

point Unity gain at the inputs to the amplifiers Telemetry carriers upstream and downstream Noise and ingress are additive from the entire node. One

bad drop can take down the entire node. Channel Plan to match bursty digital signals. No

sweep points on upstream carriers Return Sweep compensates for losses after the amp Set telemetry carrier level and sweep level to the

same thing.


Advantages of return sweep over the older methods

Not as labor intensive as the older methods. Align forward and reverse with the same stop

at the amplifier No cumbersome equipment in the field or the

headend Minimum use of bandwidth for test equipment Control over the measurements We are aligning the entire spectrum in both

directions, not just 2 carriers!


5 things you need to know to set up your return path correctly Know your equipment

– Block diagrams of amplifiers, nodes, receivers, etc.– Test Equipment

Determine reverse sweep input levels Determine reference points Optimize return lasers portion first Sweep coaxial portion of the plant


Typical Node RF Block Diagram

STATIONFWDEQ

FWDPAD

LOW PASSFILTER

HL

REVSwitch

DiplexFilter

PORT 4

Port 4Output

TP

H

L

REVSwitch

DiplexFilter

PORT 5

Port 5Output

TP

H

L

REVSwitch

DiplexFilter

PORT 6

Port 6Output

TP

H

L

REVSwitch

DiplexFilter

PORT 3

Port 3Output

TP

Fwd Signal from

OpticalRcvr.

Return Signal to Optical

Transmitter


(1) Test Points are Bi-DirectionalNotes: ALL test points can be -20 or -25dB

ALC PINDIODEATTEN

Interstage

EQ

Pre-Amplifier

Plug-InEQ

Plug-InPAD

HighPass

Filter

Diplex

FilterH

L

IGC

MainAmplifier

ReverseAmplifierPlug-In

EQPlug-In

PADLow Pass

Filter ALC Circuit

BridgerAmplifier

ACPowe

r

RF/ACFilter

RF

AC

Diplex

FilterH

L

ACPowe

r

RF/ACFilter

RF

AC

ACPowe

r

RF/ACFilter

RF

AC

AuxEQ

BridgerAmplifier

ACPowe

r

RF/ACFilter

RF

AC

Diplex

FilterH

L

ACPowe

r

RF/ACFilter

RF

AC

REVPAD

REVPAD

TRANSPONDERRF INTERFECE BRIDGER

RF TEST

REVERSERF TEST

STATION

STATION

PORT 1

PORT 5PORT 2

PORT 3PORT 6

Plug-InEQ

Plug-InPAD

BRIDGE

(1)

(1)(1)

(1)(1)

Typical RF Bridging Amplifier Block Diagram


Know your test equipment

Different test equipment operates differently.

Size Matters!


How is a reference level determined?

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From trunk return

52 dBmv max modem output23db tap

2 dB drop loss7 dB directional coupler

20dBmV at the reference pointDoes your system use this as the reference point?


ALIGNING THE RETURN PATH


Constant outputs in the return path?

Return Equip.

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If the return amplifiers were balanced with constant outputs, the levels would vary widely by the time they got back to the headend. This is due to return amplifiers having several inputs.


How does reverse sweep work?

Return Equip.

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RF in

RF out

The field unit initiates the sweep through the return path at the reference level.

1.

The headend unit receives the sweep from the field unit, digitizes it’s own trace, and sends out on a forward telemetry pilot.

2.

The DSAM receives data from thetransmitter and displays sweepfrom the headend unit

3.

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Normalizing or Storing a Sweep Reference, reverse

Return Equip.

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RF in

RF out 1. Inject correct input sweep level2. Check for adjust raw sweep level3. Store reference file

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Continuing On

Return Equip.

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RF in

RF out 1. Inject correct input sweep level2. Use the reverse sweep reference to compare and

adjust amplifier output levels

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Reverse Sweep Display

Markers

Start Frequency

Stop Frequency

Marker Frequencies

Marker Relative Levels

Scale Factor

Max Variation within Frequency Range

Fiber Optics


AfterBefore

Loose Fiber Connector :A display an RF guy can understand

SC connector not pushed in all the way


9125250

Cross section of an Single Mode optical fiber


Refraction


n = c / v

n = refractive indexc = velocity of light in a vacuumv = velocity of light in glass

IOR = Index of Refraction


Reflection


Light in an optical fiber – Total Internal Reflection


Bending


Common Connector Types

SC Commonly referred to as Sam Charlie

FC Commonly referred to as Frank Charlie

ST Commonly referred to as Sam Tom

LC Commonly referred to as Lima Charlie


Connector ConfigurationsPC or UPS vs APC

SC - PC

SC - APC

Inspect Before You Connectsm


Focused On the Connection

Bulkhead Adapter

Fiber Connector

Alignment Sleeve

Alignment Sleeve

Physical Contact

FiberFerrule

Fiber connectors are widely known as the WEAKEST AND MOST PROBLEMATIC points in the fiber network.


What Makes a GOOD Fiber Connection?

Perfect Core Alignment Physical Contact Pristine Connector

Interface

The 3 basic principles that are critical to achieving an efficient fiber optic connection are “The 3 P’s”:

Core

Cladding

CLEAN

Light Transmitted


What Makes a BAD Fiber Connection?

A single particle mated into the core of a fiber can cause significant back reflection, insertion loss and even equipment damage.

Visual inspection of fiber optic connectors is the only way to determine if they are truly clean before mating them.

CONTAMINATION is the #1 source of troubleshooting in optical networks.

DIRT

Core

Cladding

Back Reflection Insertion LossLight


Illustration of Particle Migration

Each time the connectors are mated, particles around the core are displaced, causing them to migrate and spread across the fiber surface.

Particles larger than 5µ usually explode and multiply upon mating. Large particles can create barriers (“air gap”) that prevent physical contact. Particles less than 5µ tend to embed into the fiber surface creating pits and chips.

11.8µ

15.1µ

10.3µ

Actual fiber end face images of particle migration

Core

Cladding


Types of Contamination

A fiber end-face should be free of any contamination or defects, as shown below:

Common types of contamination and defects include the following:

Dirt Oil Pits & Chips Scratches

Simplex Ribbon


Contamination and Signal Performance

Fiber Contamination and Its Affect on Signal PerformanceCLEAN CONNECTION

Back Reflection = -67.5 dBTotal Loss = 0.250 dB

1

DIRTY CONNECTION

Back Reflection = -32.5 dBTotal Loss = 4.87 dB

3

Clean Connection vs. Dirty ConnectionThis OTDR trace illustrates a significant decrease in signal performance when dirty connectors are mated.


Test!

Basic Tests– Visual Fault Locator (VFL)– Optical Insertion Loss– Optical Power Levels

Advanced Tests– Optical Return Loss (ORL)– Optical Time Domain Reflectometer (OTDR)– Chromatic Dispersion (CD)– Polarization Mode Dispersion (PMD)– Optical Spectral Analysis (OSA)


Visual Fault Locator

VFLs provide a visible red light source useful for identifying fiber locations, detecting faults due to bending or poor connectorization, and to confirming continuity.

VFL sources can be modulated in a number of formats to help identify the correct VFL (where a number of VFL tests may be performed).

FFL-050 FFL-100


Advanced Tests

Optical Return Loss (ORL) Optical Time Domain Reflectometer (OTDR)

– Detect, locate, and measure events at any location on the fiber link Fiber Characterization

– Determines the services that the fiber can be carry– Basic tests plus:

• Chromatic Dispersion (CD)• Polarization Mode Dispersion (PMD)

Optical Spectrum Analysis (OSA)– Spectral analysis for Wavelength Division Multiplexing (WDM)

systems


Introduction to OTDR

It’s the single most important tester used in the installation, maintenance & troubleshooting of fiber plant

T-BERD 4000 FTTx / Access OTDR Most versatile of Fiber Test Tools Detect, locate and measure events at any location on the fiber link Identifies events & impairments (splices, bends, connectors, breaks) Provides physical distance to each event/ impairment Measures fiber attenuation loss of each event or impairment Provides reflectance / return loss values for each reflective event or impairment Manages the data collected and supports data reporting.


Background on Fiber Phenomena

OTDR depends on two types of phenomena:- Rayleigh scattering - Fresnel reflections.

Rayleigh scattering and backscattering effect in a fiber

Light reflection phenomenon = Fresnel reflection


How does it work ?

The OTDR injects a short pulse of light into one end of the fiber and analyzes the backscatter and reflected signal coming back

The received signal is then plotted into a backscatter X/Y display in dB vs. distance Event analysis is then performed in order to populate the table of results.

OTDR Block Diagram Example of an OTDR trace


Dynamic Range & Injection Level

Dynamic Range determines the observable length of the fiber & depends on the OTDR design and settings

Injection level is the power level in which the OTDR injects light into the fiber under test

Poor launch conditions, resulting in low injection levels, are the primary reason for reductions in dynamic range, and therefore accuracy of the measurements Effect of pulse width: the bigger the pulse, the more backscatter we receive


What does an OTDR Measure ?

Distance– The OTDR measurement is based on “Time”:

The round trip time travel of each pulse sent down the fiber is measured. Knowing the speed of light in a vacuum and the index of refraction of the fiber glass, distance can then be calculated.

Fiber distance = Speed of light (vacuum) X time 2 x IOR



Attenuation (also called fiber loss)Expressed in dB or dB/km, this represents the loss, or rate of loss between two events along a fiber span



Event LossDifference in optical power level before and after an event, expressed in dB

Fusion Splice or Macrobend

Connector orMechanical Splice


ReflectanceRatio of reflected power to incident power of an event, expressed as a negative dB value

The higher the reflectance, the more light reflected back, the worse the connection

A -50dB reflectance is better than -20dB value


Typical reflectance values Polished Connector ~ -45dB Ultra-Polished Connector ~ -55dB Angled Polished Connector ~ -65dB



Optical Return Loss (ORL)Measure of the amount of light that is reflected back from a feature: forward power to the reflected power. The bigger the number in dBs the less light is being reflected.

The OTDR is able to measure not only the total ORL of the link but also section ORL

Distance (km)

Att

enua

tion

(dB

)

ORL of the defined section


Optical Return Loss (ORL)

Light reflected back to the source

PT: Output power of the light source

PAPC: Back-reflected power of APC connector

PPC: Back-reflected power of PC connector

PF: Backscattered power of fiber

PB: Total amount of back-reflected power

ORL (dB) = 10Log > 0)(B

T

PP

PAPC PPC PAPC PAPC

PT

PF PF PF

Light Source

Photo-diode


Effects of High ORL Values

All laser sources, especially distributed feedback lasers, are sensitive to optical reflection, which causes spectral fluctuation and, subsequently, power jitter. Return loss is a measure of the amount of reflection accruing in an optical system. A -45dB reflection is equivalent to 45dB return loss (ORL). A minimum of 45-50dB return loss is the industry standard for passive components to ensure normal system operation in singlemode fiber systems.

Increase in transmitter noise– Reducing the OSNR in analog video transmission– Increasing the BER in digital transmission systems

Increase in light source interference – Changes central wavelength and output power

Higher incidence of transmitter damage The angle reduces the back-reflection of the connection.

SC - PC

SC - APC


OCWR method

Optical Return Loss

Ratio between the transmitted power and the received power at the fiber origin

2 different test methods:– Optical Continuous Wave Reflectometry (OCWR): A laser source

and a power meter, using the same test port, are connected to the fiber under test.

– Optical Time Domain Reflectometry (OTDR)

OTDR method


Accuracy (typ.) ± 0.5dB

Typical Application

- Total link ORL & isolated event reflectance measurements during fiber installation & commissioning

Strengths - Accuracy- Fast & real time info- Simple & easy results (direct value)

Weaknesses - No localization

Proc

ess

Con

trol

ler

Dis

play

Coupler

Photodetector

Pulsed Light Source

Optical Continuous Wave Reflectometer

Optical Time Domain Reflectometer

ORL Measurement Methods

Termination Plug

Proc

ess

Con

trol

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Dis

play

CW Stabilized Light Source

Power Meter

Coupler

Accuracy (typ.) ± 2dB

Typical Application

- Perfect tool for troubleshooting- Spatial characterization of reflective events & estimation of the partial & total ORL

Strengths - Locate reflective events- Single-end measurement

Weaknesses - Accuracy- Long acquisition time

OTDR EventsHow to interpret a trace


How to interpret an OTDR Trace


Front End Reflection

Connection between the OTDR and the patchcord or launch cable

Located at the extreme left edge of the trace

Reflectance: Polished Connector ~ -45dB Ultra-Polished Connector ~ -55dB Angled Polished Connector up to ~ -65dB

Insertion Loss: Unable to measure


Dead Zones

Attenuation Dead Zone (ADZ) is the minimum distance after a reflective event that a non-reflective event can be measured (0.5dB) In this case the two events are more closely spaced than the ADZ, and shown as one event ADZ can be reduced using shorter pulse widths

Event Dead Zone (EDZ) is the minimum distance where 2 consecutive unsaturated reflective events can be distinguished In this case the two events are more closely spaced than the EDZ, and shown as one event EDZ can be reduced using shorter pulse widths


Connector

A connector mechanically mates 2 fibers together and creates a reflective event

Reflectance: Polished Connector ~ -45dB Ultra-Polished Connector ~ -55dB Angled Polished Connector up to ~ -65dB

Insertion Loss: ~ 0.5dB (loss of ~0.2dB w/ very good connector)


Fusion Splices

A Fusion Splice thermally fuses two fibers together using a splicing machine

Reflectance: None

Insertion Loss: < 0.1dB

A “Gainer” is a splice gain that appears when two fibers of different backscatter coefficients are spliced together (the higher coefficient being downstream)

Reflectance: None

Insertion Loss: Small gain


Fusion Splices

Direction A-B Direction B-A


Macrobend

Macrobending results from physical bending of the fiber. Bending Losses are higher as wavelength increases. Therefore to distinguish a bend from a splice, two wavelengths are used (typically 1310 & 1550nm)

Reflectance: None

Insertion Loss: Varies w/ degree of bend & wavelength


Mechanical Splice

A Mechanical Splice mechanically aligns two fibers together using a self-contained assembly.

Reflectance: ~ -35dB

Insertion Loss: ~ 0.5dB


Fiber End or Break

A Fiber End or Break occurs when the fiber terminates.

The end reflection depends on the fiber end cleavage and its environment.

Reflectance: PC open to air ~ -14dB APC open to air ~ - 35dB

Insertion Loss: High (generally)


Ghosts

A Ghost is an unexpected event resulting from a strong reflection causing “echos” on the trace

When it appears it often occurs after the fiber end.

It is always an exact duplicate distance from the incident reflection.

Reflectance: Lower than echo source

Insertion Loss: None


Typical Attenuation Values

0.2 dB/km for singlemode fiber at 1550 nm 0.35 dB/km for singlemode fiber at 1310 nm 1 dB/km for multimode fiber at 1300 nm 3 dB/km for multimode fiber at 850 nm 0.05 dB for a fusion splice 0.3 dB for a mechanical splice 0.5 dB for a connector pair (FOTP-34) Splitters/monitor points (varys with component)


Monitoring the Reverse Path Inside Plant


Major Operational Challenges

Plant Certification and Maintenance:– Elevate plant performance to ensure reliable service – HFC: Sweep & advanced return path certification– Metro Optical: Fiber and transport analysis

Monitor Performance:– Continuously monitor the health of your upstream and downstream carriers– Proactively identify developing problems before customers do– Monitor both physical HFC & VoIP service call quality– Utilize advanced performance trending and analysis to prioritize

Get Installations Right the First Time– Improve installation practices to prevent service callbacks & churn – Verify physical, DOCSIS® and PacketCable performance– Drive consistency across all technicians

Troubleshoot Fast:– When issues occur, find and fix fast– Isolate and segment from NOC, dispatch right tech at right time– Field test tools that can find problems and verify fix


Return Path Monitoring Benefits

Troubleshoot nodes faster to reduce MTTR and increase workforce efficiency

• Identify impairments before rolling a truck using both spectrum and packet monitoring technology

• Use field meters to quickly locate ingress, the most common impairment

• View performance history to understand transient problems to roll a truck at the right time to find and fix the issue

Reduce trouble tickets and customer churn by identifying problems before your subscribers

• Rank nodes using convenient web-based reports for proactive maintenance

• Easily and quickly detect impairments such as fast impulse noise, ingress, CPD, and laser clipping on all nodes 24/7

• View live spectrum, QAMTrak™ analyzers and a wide array of reports conveniently via the web


DOCSIS® 3.0 adds Capability to Bond up to 4 Upstream 64QAM Carriers!

Four times 6.4 MHz = 25.6 MHz! (without guard-bands)

Increased chances for laser clipping Increased probability of problems caused by

ingress, group delay, micro-reflections and other linear distortions

Inability to avoid problem frequencies such as Citizens’ Band, Ham, Shortwave and CPD distortion beats

Where are you going to place your sweep points?


Live Spectrum Display


Choose a carrier for QAMTrak


Getting To Know The QAMTrak Analyzer

QAMTrak Sections•Impairment Dashboard•Impairment Charts•FFT Spectrum Display•Constellation•Strip Chart•Data Tables•Control/Information Bar


QAMTrak Analyzer: Primary Sections

•Impairment Dashboard

Display in simple red light / green light format which impairments have violated admin-defined thresholds and what % of packets affected by each (rollup status)

Shows min/max/average for health metrics and impairments Provides single-click launch points to detailed charts for each impairment type


Impairment Dashboard – Two Main Sections

Top three boxes indicate HFC health– Is data corruption occurring within packets being demodulated?– How tight are the constellation points before CMTS

compensation – How well is the CMTS likely able to compensate for impairments

present

Bottom six boxes indicate how frequently each impairment type is occurring– How often does a packet come across which violates threshold?– What is min/max/average for each impairment type?– Which impairment(s) are my biggest problem right now?

Clicking any button will launch a maximized impairment chart window within the QAMTrak Analyzer


Impairment Dashboard – General Interpretation

Impairment/Health Metric LabelRollup CounterPercent of packets since start of QAMTrak session which have violated admin defined threshold for that impairment or metric

Latest ValueValue for last packet demodulated or current packet highlighted for historical packet analysis

Min/Max/AverageMinimum, Maximum, Average values for all packets captured during current QAMTrak session or since last reset

Caveats:Only the latest 600 packets are displayed on strip chart and in tables

Min/Max/Average and Rollup Counter can reflect packets which are not visible in strip chart of tables for sessions with >600 packets captured!

Latest StatusPass/Fail status for last packet demodulated or current packet highlighted for historical packet analysis

( or )

Session Status (Background Color)Indicates whether impairment threshold has been violated during session


Primary Impairments

•Impairment Dashboard

Provides detailed display for five primary impairment types plus codeword error strip chart – supplement Impairment Dashboard

Charts update for each packet in live mode or historical packet review mode Y-Axes can be manually rescaled or auto-scaled, charts can be resized, many

other options available through Flash interface

•Impairment Dashboard•Impairment Charts


Primary Measurements

Provides Spectrum Analyzer display without opening a separate window FFT-based spectrum analyzer – will look different than standard PathTrak

SA Display will show what spectrum looked like at time of packet capture

when reviewing captured packets in paused mode

•Impairment Dashboard•Impairment Charts•FFT Spectrum Display


Upstream Constellation

Can display Equalized, UnEqualized symbol locations, or both Can show latest packets, all historical packets, or both Displays constellation packet by packet when reviewing historical

packets

•Impairment Dashboard•Impairment Charts•FFT Spectrum Display•Constellation



Separate chart traces for Equalized MER, Unequalized MER, and Carrier Level (on second Y-Axis)

Detailed packet info available using hover function Can use arrow keys to review historical packets one at a time

•Impairment Dashboard•Impairment Charts•FFT Spectrum Display•Constellation•Strip Chart



Users can toggle between strip chart, all-packet data table, and unique MAC data table

Tables are sortable by all rows, can be exported to .csv file Data can be copied from tables to clipboard for pasting into other apps

•Impairment Dashboard•Impairment Charts•FFT Spectrum Display•Constellation•Strip Chart•Data Tables


PathTrak WebView

CPE MAC Address

Code Word Errors


PathTrak WebView QAMTrakCPE MAC AddressCodeword Error DetectionEqualized and UnEqualized MERMicro-reflections In Band Response – RippleGroup Delay Ingress Under the Carrier Impulse Noise Detection


DOCSIS Downstream Codewords

122 of each RS codeword’s 128 symbols are data symbols, and the remaining six are parity symbols used for error correction.

–ITU-T J.83, Annex B states that the data is “…encoded using a (128,122) code over GF(128)…” which shows each RS codeword consists of 128 RS symbols (first number in first parentheses) and the number of data symbols per RS codeword is 122 (second number in first parentheses), leaving six symbols per RS codeword for error correction.

DOCSIS downstream RS FEC is configured for what is known as “t = 3,” which means that the FEC can fix up to any three errored RS symbols in a RS codeword.

Downstream Monitoring


HomeHub/HFC

The Cable Video Network

Master/Super Headend

MPEGHeadendIP Transport

Video Passes Through Four Separate Operational Layers Before it Reaches the Home.

But The MPEG Edge is the most critical layer and poses the most significant risk to video quality.

Outside Plant

CMTS

STB

PhonePC

Modem

DPI

MPEG Mux.

Encryption

Modulation

IP L2/L3Core

Network

Origination and

processing

Transport through the IP network

MPEG edge-processing

RF combining

VOD

Distribution over HFC

Combiner

Inside PlantOff-air Ingest


The RF edge is home to the most complex equipment in the network

Current monitoring solutions focus on the national backbone and on validating the content when programming first enters the network.

Often QoS issues (like tiling) are introduced by the complicated equipment at the network edge

If you aren’t monitoring at the RF edge, only the subscriber will have visibility to the impairments– You’ve caused these problems, but you don’t see them

Troubleshooting is initiated by a customer complaint and without this “edge” visibility you may spend multiple truck rolls and weeks isolating the source.

CMTS

DPI

MPEG Mux.

Encryption

Modulation


RF combining

Combiner

Off-air Ingest


Often QoS issues are introduced by the complicated equipment at the network edge

CMTS

DPI

MPEG Mux.

Encryption

Modulation


RF combining

Combiner

Off-air Ingest

Local Off-Air Ingest:• Provider issues• Antennas• 8VSB Receivers• Muxes to groom for

regional networks

Program Insertion:• Quality of ad being spiced• PCR Discontinuity• Decoding/Timing of DPI information

Multiplexing:• Streams from regional

networks• Grooming• Transrating• Over-compression• Equipment

configuration

Encryption:• Encryption not-enabled• Equipment configuration

Modulation:• MPEG to RF• Equipment configuration• Oversubscription

RF Combining:• Poor cabling• Poor Isolation• Loose connectors• Driver/Isolation

amp issues

And currently this is the last place you’re monitoring the video?


You may already have monitoring…

… but your customers are still seeing issues

Outside Plant

CMTS

STB

PhonePC

Modem

DPI

MPEG Mux.

Encryption

Modulation

IP L2/L3Core

Network

VOD Combiner


Content monitoring has traditionally been expensive. Typically deployed only where

content enters the network. Content Monitoring is typically not

deployed at the very edge of the network

That leaves the most vulnerable spot in the network, in the dark


Detailed MPEG analysis detects the important issues

Video/Audio QoS issues caused by equipment in the headend or local network are transport related and can be identified without performing content analysis– Video freeze result of lost programs or video PIDs– Audio loss as a result of missing audio PIDs

Other frozen/black/no-audio that are the result of content (and not the programs) in almost all cases isn’t anything local system personnel can do anything about.

Content analysis also limited to unencrypted programming – preventing use at edge of the network.

Content analysis is impractical and costly at the edge of the network.

Investment is significantly more effective if focused on transport tools that provide complete visibility and

troubleshooting directly at the edge modulator.


Get complete visibility – “Wrap the Edge”

MVP-200 MVP-200 RSAM

Video Monitoring is a video monitoring solution optimized for the network edge– MVP-200 probe (full line-rate MPEG over GigE)– RSAM probe (Digital video RF, Analog video RF, DOCSIS)– PVM – Simple, lightweight, centralized system to tie it all together.

Outside Plant

CMTS

STB

PhonePC

Modem

DPI

MPEG Mux.

Encryption

Modulation

IP L2/L3Core

Network

Origination and

processing

Transport through the IP network


RF combining

VOD

Distribution over HFC

Combiner



Example – Tiling

The RF probe consistently reported Continuity error alarms on a QAM. This clip shows what your Customer experienced

– the impact of these CC errors


Another Example - Video Freeze

How do you explain this to

your customer??

HLN_13 (27) MVP Trap QAM 28 OUTPUT

Trap Console received trap traps/event.Time: January 6, 2011 6:03:10 AM EST STB: 27 PID ID: -1 PID: -1 PID Type: Event ID: programLost Event Severity: minor From MVP: 10.15.21.24 Card: 2 Source IP: XX.240.203.206:60000 Dest. IP: XXX.48.81.115:28115


Trap Console received trap traps/event.Time: January 6, 2011 6:03:17 AM EST STB: 27 PID ID: -1 PID: -1 PID Type: Event ID: programLost Event Severity: major From MVP: 10.15.21.24 Card: 2 Source IP: XX.240.203.206:60000 Dest. IP: XXX.48.81.115:28115


Trap Console received trap traps/event.Time: January 6, 2011 6:03:21 AM EST STB: 27 PID ID: -1 PID: -1 PID Type: Event ID: programLost Event Severity: clear From MVP: 10.15.21.24 Card: 2 Source IP: XX.240.203.206:60000 Dest. IP: XXX.48.81.115:28115

Event Starts - MinorContinues - Major

Ends - Clear

Below are the alarms generated for the above event from the MVP:

Click on video to play


Knowing is only half the battle…

Monitoring tells you when you have a problem.– To isolate the problem source, the

ops staff needs troubleshooting tools as well.

Remote access via PVM gives service level visibility at the edge of your network, from anywhere.– Critical in digital video, where

problems are intermittent and spurious.

– Critical at the edge, where staff may be hours from the equipment.

JDSU’s monitoring probes are unique in providing integrated real-time analyzers for troubleshooting.

Troubleshoot anytime, anywhere.


Video Monitoring Application

Identify and segment problems using intuitive displays– RF or MPEG?– Outside plan, headend or source issue– Widespread or localized?– Intermittent or persistent problem?

Find root-cause with advanced troubleshooting– Click an event or status bar to get a live display– Capture transport streams to share with your network equipment

suppliers– View table decodes to understand impairments

Access Historical PM Reports– NetComplete– Per Program, Per Node

– Worst Offenders– Key Performance Indicators


Network Management System Integration

SNMP and XML API:– Designed to be flexible and easily integrated

Per Program and Per Stream, real-time data– Real-time per program status to one system view


Why Video Monitoring? Solve real problems today

– Optimized for an operations staff• Real-time alarming direct to local staff• Complete RF component for analog, digital and DOCSIS

– Cost-Efficient• Fraction of the cost of conventional content monitoring

– Proximity to the Edge• Monitor right at hand-off to access

network, visibility for entire digital network

– Isolate problem sources• Integrated remote analyzers at IP

and RF

Thank You

Plant Reliability

Documents

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