5530NA Hanoi Training.ppt

Alcatel-Lucent University Antwerp

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University

5530 Network Analyzer

R4.1+


University


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University

Introduction

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5530 NA

5530 NA on-demand fault diagnosis tools. single-end line testing dynamic line management network analysis tools Northbound interface to upper-layer OSS applications. Multi-vendor plug-ins for third-party nodes

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System overview 5530 NA

Alcatel 73xx DSLAM3rd party DSLAM

5523 AWS 5530 NA

http https http

SNMP v1SNMP v3tftp

CPE xDSL modem

https introduced from R2.3clustering introduced from R3.3

5530 NA cluster

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5530NA – ASAM communication

SNMP TFTP

Network diagnosis

Protocol Handler

Network analysis

5530 NA

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Network Diagnosis

tools to quickly detect, resolve & troubleshoot DSL outages, actively and pro-actively.

Line State Diagnosis (R3.3+) Equipment fault diagnosis Real-time dashboard Line quality diagnosis: diagnosis and monitoring over time Short Line Quality Diagnosis (R3.3) Single End Line Testing: SELT Line Quality Validation (R4.1)

SELT can be used for loop qualification before a CPE is installed fault detection and localization when the CPE cannot be synchronized

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Network analysis

manage your installed DSL infrastructure pro-actively. Assess the impact of the introduction of new DSL

services and plan maintenance activities in your DSL network

Collect network-wide: line classification DSL operational behaviour information

Network-wide analysis functions: Network stability Network performance CPE classification

Detailed reports on network characteristics


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University

Getting started

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Connecting to the 5530 NA

Use your browser to connect to the 5530 NA http://<IP-address 5530NA>:8080 https://<IP-address 5530NA>:8443

5530 NA R2.3+ introduces secure http (https): Depending on your browser, one or more security

certificates may appear. Click on the Yes or Ok button to continue.

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Main (R3.3+)

NA menu options

Profile of logged in user

Access to help- user guide

About 5530 NA- product information- license information

Logout

Home- overview page (this page)

Current diagnosis inspections in database of 5530NA- number of inspections per type- inspection health- clickable per inspection type per health

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Inspect field

Port resource identifier TL1: <DSLAM-name>:<rackID>-<shelfID>-<slotID>-

<portID>Example: ISAM5:1-1-1-6

AWS: <DSLAM-name>:R<rackID>.S<shelfID>.LT<slotID>.<portID>

Example: ISAM5:R1.S1.LT1.6 User labels Customer ID Inspection ID

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Configure element manager(s)

Creation of a new element manager: Click on the “Add EML provider” button

Provide the IP address and account data for the AWS

Click on the “Add URL provider” buttonProvide name and URL for host fileFile://xxxxxxxxxxhtml://xxxxxxxxxxftp://yyyyyyyyyyyyy

Discover managed networks Click on the “Synchronise ASAMs” button

Display discovered ASAMs Click on the link behind the configured EML Reachability from the 5530 NA to ASAMs is shown

5530 NAconfiguration

Synchronization

• Add xxx provider• Delete• Edit (R2.3+)• Synchronise DSLAMs• Show synchronization report• Synchronization settings• Display ASAMs/provider

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Display discovered ASAMs

Click on the link behind the configured provider Reachability from the 5530 NA to ASAMs is also

shown

Reachable Unreachableor not supported

Synchronize button


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University

Network Diagnosis

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Network diagnosis Applications:

on-demand trouble shooting on a line (line monitoring)

identifies probable cause and provides repair advice equipment problem diagnosis (one-shot diagnosis)

similar to AWS Main characteristics:

monitoring of line parameters over time automatic analysis in real-time time saving can be executed by customer service representatives

no technical expertise required automated collection of:

max. attainable bit rate, attenuation, noise margin, bit loading, ...

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Network diagnosis

Diagnosis of one line starts with line state diagnosis: Line configuration overview Last detected CPE type SELT reference if available Line classification history Access to other line diagnosis tools

Dashboard, SELT, line quality diagnosis (LQD), short LQD, Line Quality Validation (LQV –> R4.1 only)

Line parameter summary If line is down equipment fault diagnosis is started Access to other NA tools related to that port

Diagnosis & SELT management, event history & NA configuration

Start “Line State Diagnosis”

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Line State Diagnosis report (R4.1)

New!

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Equipment fault diagnosis

If the line is DOWN, the 5530 NA diagnoses the problems.

The diagnosis verifies the existence and status of the following:

ASAM reset LT card & applique LT Port xDSL Line …

“detected equipment fault problems” window

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Dashboard inspection

real-time views of a DSL: display operational parameter values for the DSL detect line quality degradations.

updated every 10 s information appears in a separate window. Results cannot be saved. Window layout can be saved

data shown Bit rates, attenuations, noise margins, ATM traffic, coding

violations & Forward Error CorrectionsEach window can be expanded

Alarms & events Configuration details

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Dashboard inspection

Hide/unhide measure pointsMaximize windowHide window

Hide/unhide data window

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Line quality diagnosis Start a (short) line quality diagnosis

Click on ‘short diagnosis’ or ‘diagnosis’ Provide collection mode parameters

For LQD only (not short LQD) Click on ‘Continue inspection’ Parameters monitored:

Line status PM data, attainable & actual line rate ATM traffic Noise margins & attenuation Bit loading and bit swapping Coding violations & Forward Error

Corrections SNR, QLN, Hlog Output power …

Line state diagnosis

report

(Short) Diagnosis

inspection?

Provide monitoring& collection period

parameters

cancel

Monitoring

continue

5530NA Home

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Inspection principles

NE

...

tHistorical line data(data in MIB)

Line state report Monitoring phase(in background)

Monitoring configuration

Notification sent

1. Automatic export?2. Data purged

Purge timeout

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Diagnosis concept

LQD measurement symptoms 1 or more symptoms (combined or not) possible problem

Detected problem also based upon extensive Alcatel field experience

No 100% certainty confidence level given Confidence level: based upon the combination and clarity of

symptoms

Line Quality Diagnosismeasurement

Symptom x Detected problem Axx% confidence

Symptom y

Symptom z

Symptom …

Detected problem Byy% confidence

Detected problem Czz% confidence

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Block line quality diagnosis

Block line quality inspection Line quality diagnosis on multiple DSL lines in one go

Max. block inspection size: 200 to 500 DSL lines separated by a comma in the inspect field

Could also be started from network analysis classification reports

No line state report is given

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Block Inspection Execution

5530 NA schedules Line Quality Diagnosis on the individual lines

Execution time depends on Number of lines contained in inspection block Max. number of inspections per NE Block inspection quota

Inspection management Cancel, purge of the block inspection is propagated to all

contained diagnosis processes

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Single End Line Testing

SELT test on lines that are not in sync. SELT can detect open and short loops up to a certain

lengthSignal reflection measurement

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Managing inspections

Inspections appear in the current inspection list until purge timeout [hours] Dashboard inspections only appear in list when running.

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Managing inspections

View: look at report detailsDelete: report deleted from 5530 NAStop: stops running inspectionEdit: Edits description field

Health: good or bad/

Sort according to (blue items are clickable)

Filter criteria

Sort ascendingSort descending

Depending NA release this window might differ slightly

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5530NA homepage

When logging into the 5530NA the home page gives an overview of all inspections in the database

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G.SHDSL Support R2.3+

Network Diagnosis and Analysis support for G.SHDSL

Two- and four-wire mode Repeaters not supported

Network Diagnosis Package Equipment Fault Diagnosis Line Quality Diagnosis

Detection of line instabilities based on MTBE

Real-time dashboard Network Analysis Package

Network AnalysisLine classification

taking MTBE into account (line instabilities)

Network Detail Reports

Measurement of Bit rate (US and DS) Attenuation (US and DS) Noise Margin (US and DS) Coding Violations


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Network Diagnosis interpretation

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Network Diagnosis

Loop diagnostic mode = robust initialization that allows to perform DELT measurements even when line is not able to get into showtime mode

Available for ADSL2 and VDSL2

in-service monitoring (with optional carrier data mode)

synchronized

DELT: loop diagnostics mode

loop diagnostics (LD) initialization

SELT: reflectometry

synchronization/LD not possible

e.g. impulsenoise

e.g. cable cut

NEW IN R4.1NEW IN R4.1

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DELT parameters

Measurable parameters, but they are not necessarely shown in the 5530 NA reports

DELT: loop diagnostics mode

loop diagnostics (LD) initialization

e.g. impulsenoise

•ISM = In-Service Monitoring•CD = Carrier Data•CD+ = Carrier Data with reinit•LD = Loop Diagnostic

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Detected problems

Bridgedtap

MissingPOTS/ISDN

splitter

RFI

Crosstalk•Low-frequency•ISDN, HDSL, SHDSL, T1/E1 disturber

•Open circuit•Intermittentcontact

Shortcircuit

Degradedcontact

Impulsenoise

Untwistedin-housewiring

CPE interoperabilityproblem

Loopunbalance

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Definitions

Line stability Line is unstable: (on average) spontaneous resync within

6 hours! MTBR = Mean Time Between Resynchronisations

Line quality Poor quality: lots of code violations

CV = CRC error on ADSL superframe MTBE = Mean Time Between Error Events

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Definitions: MTBE

Case 1: Line 1: Line 2:

Which line has best quality? Case 2:

Line 1: Line 2:

Which line has best quality?

1Error… …

t

t100Errors

24 errors

400 errors

t

t

Rate: 500kbps

Rate: 5Mbps

MTBE = rate x total showtime/# of errored events

Error event

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Definitions: Service Stability

Service degradation because of transmission errors or spontaneous resynchronizations.

On the line state report

On the LQD report

From NA R3.1 these thresholds are configurable through the service templates

MTBE<1E+08bits, MTBE<60s or MTBR<6hMTBE= show-time / #CV events [sec]MTBE= show-time x rate/#CV events [bits]MTBR= show-time/spont. resyns [sec]

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xDSL performance

Does the DSL line match the expected performance for a specified attenuation?

undetermined - no data for attainable bit rate or attenuation Degraded:

attainable bit rate < bad attainable bit rate curve Medium:

bad attainable bit rate < attainable bit rate < good att. bit rate

Good: good attainable bit rate < attainable bit rate

Configure xDSL performance settings system settings Only shown in “classification history” in link state

diagnosis report

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xDSL performance

Graph specifies the classification for xDSL performance

Atta

inab

le b

it ra

te

Attenuation

Attainable (good)Attainable (bad)

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Monitoring configuration (R4.1)

Automatic duration is 6 or 18 hours of show-show-timetime. Decision based upon comparison of historical service stability with the current!

NORMAL_INIT: Enable line reinitialization: allows collection of QLN, Hlog

ROBUST_INIT: Enable Loop Diagnostics (LD) mode

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Line quality diagnosis report

5530 NANetwork

diagnosis

diagnosis management

• Inspection ID

Notification mail link

Show details

• Show details

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LQD report windows

Service stability Based on configured threshold values of MTBE & MTBR in service

template CPE type

Displays the friendly name for the CPE type as defined in the CPE filter.

Profile details of xDSL service & xDSL spectrum profile

Communicated through EOC

R4.1: name of used service template is shown

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LQD report windows

Service stability & xDSL performance daily line classification (network analysis)

Network analysis reports only average line classifications

on a weekly or monthly basis

Daily line classification(network analysis)Previous & current LQDs

Inspection ID

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Report export

Report can be exported to 2 different file types CSV export

Data for use in a spreadsheet Data put in simple ASCII file separated with commas

Min. interval is 3 minutes (even if polling period is smaller) RAW export

Proprietary 5530 NA file (R2.3)<name>_id_#_.raw.gz

XML file (R3.1+)<name>_id_#_.xml.gz

Full data detail for archiving and re-importing in another serverImport via Network diagnosis > Diagnosis management

Files are saved on operator’s machine (not the 5530 NA server)

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LQD report windows

Confidence based on severity and symptoms detected A complete description of all problems is provided in

the user guide of the 5530NA.

Detected RFIs

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LQD report windows

Show details of LQD report Details include monitoring information, parameter

summary, event summary and a collection of diagrams representing all collected data

Specific LQD report detail terminology: Spontaneous resync: re-init within 40s Profile switch: change in xDSL profiles, the detected line

quality problems are based on the symptoms since the last profile change

Coding Violations: CRC error in ADSL superframe Forward Error Corrections: corrections made by Reed

Solomon Quiet Line Noise: representation of actual noise on line Transfer function magnitude (Hlog):

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Inspection info & event summary

MTBE is for up and down together MTBR is average for total showtime

= showtime period / # of spontaneous resyncs

Bitswaps > actual bitswapping eventsNOT the number of bits swapped! (found in event details)

Clicking on the event will provide you the details

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Event summary

Bitswaps Date & time of bitswap event Number of bits swap

Spontaneous resync Date & time of resync event Total duration of the resynchronisation

Profile switch Number of port configuration

changes Collection failure Robust Resyncs

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Collected data graphs: guidelines

All collected data is put into several graphs where for the majority these rules apply

Line downCollection failureCollector down

Measurement data 1Measurement data 2Measurement data 3

Mea

sure

d da

ta s

cale Loop

Diagnostics

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Bitloading contour

Bitloading in time

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Bitloading

Variance [bits] Represents the variation in bits of that carrier for the total

showtime

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SNR

Variance represents the average variation of the SNR over the

spectrum

Robust init results

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Bitrate graphs

Rates shown: Actual bitrate Attainable bitrate ATM traffic

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Coding violations graph

CV = CRC error in ADSL superframe These errors are after correction by Reed Solomon

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Forward Error Correction graph

FEC: number of bytes corrected by Reed Solomon during polling interval.

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Noise margin graphs

Noise margin depends on configuration in the ADSL line profile Modem could lower or increase output power

Noise margins show Configured noise margins & actual noise margin

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Attenuation graph

Attenuation on a customer line should remain stable

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Output power graph

Output power can depend on noise margin configuration

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Line Quality Validation (LQV)

LQV : inspection to validate the operational behaviour of a line

Very lightweight Polling once every 4 hours (configurable in service template) Stops after 6 hours of show time –OR- after 7 weeks of

monitoring Only data needed to determine the operational behaviour is

collected (calculation of MTBE & MTBR) The (only) result is the stability of the line :

OKNOKUnknown

Notification sent by e-mail

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Line Quality Validation: duration

Validation monitoring duration = minimum amount of showtime required to decide that line is stable/risky = 6 hours by default (configurable)

Decision that line is unstable can already be taken at earliest when first sample is taken (after 4 hours) (when MTBE/MTBR cannot fall below threshold for unstable line anymore even if remainder of required showtime would be error free)

Maximum duration: 7 days

InitiationLQV validation

polling period

validation monitoring duration

data collection point + decision stable/riskydata collection point + decision unstable

Show

time

dura

tion

line upline down


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CPE filters

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CPE filters

In the EOC some parameters are communicated about the CPE

System vendor & System Vendor model Modem vendor & modem vendor model Serial number

Based on these parameters we can assign a CPE to a certain category and give it a friendly name

Friendly name shown in diagnostic reports Category used in Analysis reports Certain CPE types can be blacklisted

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Blacklisted / not interoperable

Configuration > CPE filter > Definition Blacklisted

User is advised to use a CPE that is not on the black list. A line quality diagnosis cannot be performed for the

blacklisted CPE Not interoperable

If blacklist is configured by setting the “Not interoperable” flag True, a LQD inspection can be started even when the CPE is blacklisted!

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CPE filter definition (Black/White List)

Create new CPE category / friendly name Shows all discovered blacklisted CPE categories in table

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CPE Filter Editor

Define details per CPE category System IDs & models Modem IDs & models Serial number Blacklist details: blacklisted and/or not interopable

Define filter order Once a match is found for a CPE it is not matched to the next

entries

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CPE filter in action

In the line state diagnosis report and the line quality diagnosis report the CPE type is indicated by the friendly name


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Service providers & ports

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Used for wholesale Each port assigned to a service provider A user belonging to a service provider can only operate

on those ports

Service provider

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Configuring the Service provider

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Assigning a user to a Service provider

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Port management

Specifies user friendly label for the port Specifies service template to be used for operations on

the port Assigns the port to a service provider Specifies the current DLM state of the port Available via

Line State diagnostics report Main menu: Configuration > ports management

5530 NA Configuration

Ports management

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Configuring ports

Methods to configure a port Configure one-by-one manually

Import from XML file triggered by userSpecify the list of ports in an XML file & import

through GUI

Import from XML automaticSpecify the list of ports in an XML file & place the file

in port import path (system settings), which is “/var/tmp/8080” by default

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Configuring ports manually 1/2

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Configuring ports manually 2/2

The line state diagnosis report allows to add/modify the port configuration Labels Service template & Service provider DLM state

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Configuring ports via XML

Configuration Port management Bulk operations tab

Enter filename of XML file<!ELEMENT DlmMapping (Mapping+)>

<!ATTLIST DlmMapping version CDATA #REQUIRED >

<!ELEMENT Mapping (#PCDATA)>

<!ATTLIST Mapping port CDATA #REQUIRED label CDATA #IMPLIED serviceTemplate CDATA #IMPLIED serviceProvider CDATA #IMPLIED dlmState CDATA #IMPLIED >



<DlmMapping version="version 1.0">

<Mapping port="frodo:1-1-2-1“ label="f21“ serviceProvider="ServiceProvider1“ serviceTemplate="ServiceTemplate1“ />

<Mapping port="frodo:1-1-3-1“ label="f31“ />

</DlmMapping>

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Bulk import of ports via XML

XML file on server side


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Network analysis

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Network analysis overview

Build-up operational database of DSL Statistical collection of key operational DSL

parameters across entire installed base

Classification of installed based: red, yellow, green clusters (analysis report)

Assists with introduction and deployment of advanced DSL services

Line classification basis for upgrade decisions

Helps to identify poor lines and network problems (e.g. strong crosstalk)

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Data collection principle

Inventory of all configured DSL lines X datapoints for each line,

The more datapoints the more confident the end result. only one sample a day. datapoint = data/counter collection of historical line parameters

line rates, noise margins, attenuation, CV interleaving, CPE info, cust. ID …

Data collection is responsibility of data collector. Data collected at a random time

At the end of each day the reports are generated

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Data storage

5530 NA can store several sets of network assessments. This helps to determine the variation over a period of

time. Only one assessment can be active at a given time!

The three types of network assessments are: Planned Current Previous

From R2.3 up to X assessments can be stored on the 5530NA

X is configurable via system settings (default = 12)

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Network assessment principle

Snapshotn-x

Snapshotn

tNetwork Assessment

DataCollection

(continuous)

DataStorage

Reports

Aggregation period:1 week or 1 month

The NA polls the entire network every day For enabled nodes

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Analysis process

Assessmentprocess

Operational xDSL Parameters+

classification data

Network Collector

NA Export

Network Analysis Network Details

Operator

Assessment Management

Administrator

Network analysis Network details

Analysisprocess

REPORTING

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Assessments management: overview table

AssessmentAssessment Assessment

PLANNED CURRENT PREVIOUS

AssessmentProcess

Network Collector

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Assessments management: assessment shift

PurgedAssessment Assessment

PLANNED CURRENT PREVIOUS

Assessment

Created

Shift happens when CURRENT is COMPLETED and PLANNED start date is reached

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Data collector

On which DSLAM do we enable data collection? Start data collection Stop data collection Collection statistics Failure log

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Plan network analysis

Plan a new network analysis & provide:

Aggregation periodOver which period do we

generate reports1 wk or 1 month

Start timeImmediate or after current

period

Only one assessment can run at a time

5530 NAMain menu:

Analysis

Report definition

• Apply changes• Reset values•Delete

Periods

Provide parameters

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Report Filters

Use filters to determine the criteria on which reports are created, including the detail reports.

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Filter Definition

Different criterias are available and can be combined

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DSLAM selectors

Seperate ASAMs by a comma Check if ASAMs are known by 5530NA

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Reporting

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Network analysis conclusion

Statistical collection of key xdsl parameters of all lines

Necessary tool to plan maintenance activities

Invaluable tool when planning the introduction of new services

Analysis capabilities based on Alcatel’s experience

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Network detail report capabilities

Provides a detailed report on the behaviour of your network Attainable bitrate vs attenuation contour plot graphs Attenuation upstream vs attenuation downstream contour plot

graph Attainable bitrate histograms Attenuation histograms Attainable bitrate vs attenuation line graphs Noise margin histograms Output power histograms

Visualises all retrieved data of the selected network assessment

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5530NA Homepage & network stability analysis

When logging into the 5530NA the home page shows the current stability analysis pie chart

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Trigger configuration

Used to trigger commands if changes are found in the analysis data for certain parameters.

The collected data is compared with data collected the previous day.

Triggers allow the 5530 NA to be proactive in maintaining the network to offer improved data reliability and automated network

diagnosis. Following changes are monitored to trigger specific actions:

CPE type customer ID stability profile service template

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Trigger configuration

ActionsChanges Configure actions

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Triggers in action

Here the stability degradation triggers an automatic LQD To view all automatically triggered quality diagnostics filter

on user name: Analysis triggerAnalysis trigger


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University

Network analysis interpretation

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Analysis report: breakdown

line export

xDSL line TL1 addressesStored on server (/var/tmp)

Start a block line quality diagnostics

5530 NA Analysis

Reporting

Analysis reports:Stability analysisPrequalification compliancePerformance analysis

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Confidence histogram

Confidence is based upon the number of datapoints collected all datapoints collected = 100% confidence Less datapoints give a lower confidence

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Showtime distribution graph

Only for stability analysis report

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Report header

Only for Analysis reports

Filter used to generate reports

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Stability & Performance Analysis Report

Stability Analysis Classified according to line stability Line stability is defined in service template 3 categories

Stable, Risky & Unstable Performance Analysis

Classified according to line performanceAttainable bitrate vs Attenuation

Performance graphs configurable via system settings 3 categories

Good, Medium & Bad

Category 1Category 2

Category 3

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Prequalification compliance report

The prequalification compliance report classifies the lines according to their prequalification health.

default prequalification health rule (defined in the service template):

Actual LR < Planned LR => NOK

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CPE categories report

CPE category analysis report each bar represents the number of CPEs in a CPE category

CPE categories configurable via Configuration > CPE filter

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Active ports analysis report

You can use the Active ports analysis report to generate a Prequalification health reportPrequalification health report and a Detailed bit rates Detailed bit rates reportreport for a DSLAM selector.

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Detail reports

ADSL, ADSL2, RE-ADSL, ADSL2+, SHDSL, and VDSL report details, which are displayed in graphs, show the relationship and distribution of operational parameters.

You can only view network assessment report details on the second day of collection.

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attainable bitrate vs attenuation contour plot

The color indicates how many lines have an attainable bitrate and attenuation in that range

Majority of lines here have a high attainable bitrate with a low attenuation

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Attenuation contour plot

Attenuation of a line is in relation to the length of the line There should be a linear relationship between the attenuation

downstream and the attenuation upstream (see graph)

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Attainable bitrate histogram

Red bar indicates number of lines that have that attainable bitrate

Blue line is the accumulation of all lines in percentage Apc. 5% of lines can not reach 3Mbps

downstream upstream

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Attenuation histogram

Red bar indicates how many lines are within that attenuation interval

Blue line is the accumulation of all lines in percentage

downstream upstream

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Output Power histogram (R2.3)

Red bar indicates how many lines are within that output power interval


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Attainable bitrate vs attenuation line graph

For a certain attenuation range how many lines can reach that bitrate

Attenuation is an indication for the length of a loop

downstream upstream

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Noise margin histogram

Red bar indicates how many lines are within that noise margin interval


downstream upstream

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Exporting: /opt/ni/bin/na_export.sh

Exporting of assessment and operational data Login on NA server as ni user

/opt/ni/bin/na_export.sh <path & filename>

Script will request which data to export

<filename>: filename of the dumpfile

This creates a clear text file (CSV) with your assessment data

Could be re-imported in xls or other applications

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Data interpretation

Correct interpretation of the data can only be done by understanding the xDSL line profile parameters in your network.

Typically noise margin parameters have a large impact on your 5530 NA result

Lower max. noise margin modem might lower its output power

Lower output power reduced attainable bitrate (this makes it more difficult to assess your network for an upgrade)

But because the modem can increase its output power in case of increasing noise or higher requested bitrate making exactly the upgrade possible

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Sample report: bad connectors

suspected capacitive coupling due to bad connectors: typically RJ11 connector oxidationsuspected capacitive coupling due to bad connectors: typically RJ11 connector oxidation impedance is inversely proportional with the frequency so upstream will suffer more

upst

ream

atte

nuat

ion

[dB]

downstream attenuation [dB]

> upstream attenuation is higher than upstream attenuation is higher than expectedexpected

• for (small) percentage of lines

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Sample report: ISDN crosstalk

upst

ream

max

atta

inab

le b

itrat

e [k

b/s]

upstream attenuation [dB]> suspected ISDN crosstalk into US band of ADSL over POTSsuspected ISDN crosstalk into US band of ADSL over POTS

> upstream attainable bitrate is lower than upstream attainable bitrate is lower than expectedexpected

• for (small) percentage of lines

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www.alcatel-lucent.com


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University

DSL technology refresh

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Quadrature Amplitude Modulation (QAM)

Transmitted data = Constellation

2

3

1

0

-1

-2

-3

0,5 1 1,5 2 2,5 3

1111 1001

0000

00110111 0101 0001

0110

1110

1101 1011

1100 1000 1010

0100 0010

1001 0000 1111

Symbol length (Ts)

Symbol is represented by a variation of amplitude & phase for a particular frequencyy = A . sin (2 f.t + )

4 bits/symbol>> QAM-16

t

A

A

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QAM and Noise

Constellation

1111 1001

0000

00110111 0101 0001

0110

1110

1101 1011

1100 1000 1010

0100 0010

0

2

3

1

-1

-2

-3

0,5 1

1001

Parasite noiseSame frequency

Amplitude Phase

The Shannon-Hartley theorem : Capacity bps= 1/3 x W x SNR x G

0

2

3

1

-1

-2

-30,5 1

1011

Transmit Receive

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Bits/symbol QAM Signal/Noise ratio (dB) for BER<10-7

4 QAM-16 21,8

6 QAM-64 27,8

8 QAM-256 33,8

9 QAM-512 36,8

10 QAM-1.024 39,9

12 QAM-4.096 45,9

14 QAM-16.384 51,9

SNR/QAM relationship

Relation between the SNR and the max. QAM. (QAM is directly linked to the line rate)

To obtain a certain speed we need a min. SNR!

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Discrete Multi Tone (DMT)

For DSL, multiple carrier frequencies are modulated on the 1 ADSL line using QAM.

These frequencies are equally spaced and for each carrier the SNR is measured to determine the maximum achievable QAM.

The sum of all frequencies is put on the line

This concept is called Discrete Multi Tone (DMT)

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Discrete Multi Tone example

Ts (Symbol Time)

QAM-4 f1

QAM-16 f2

QAM-4 f3

= DMT

1 DMT Symbol

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#bits per carrier

Bits/carrier

Carriers

23456789

1011121314

Maximum value after SNR measurement per carrier at startup

Possible working value at startup

1

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Bit swapping

After start-up we‘ll use a lower QAM than possible on most of the carriers

measured SNR at startup determines maximum possible QAM at start-up

E.g.: max. QAM-4096 (12 bits per symbol) used QAM on that carrier : QAM-1024 (10 bits per symbol) 2 extra bits that could be allocated

During show-time, SNR is measured regularly (default every sec)

if SNR degrades lower QAM bits of that carrier will be reallocated to other carriers (where max. QAM > actual used QAM)

modems spread out the reallocated bits over numerous carriers.

127

Bit-swapping explained

Bits/carrier

Carriers

23456789

1011121314

1

Sudden frequency interference decreases SNR on a number of carriers

Current max. bits/carrier

Current used bits/carrier

128

Bit-swapping explained (2)

Bits/carrier

Carriers

23456789

1011121314

1

A lower SNR also lowers our max QAM (the number of bits on those carriers)



Affected frequencies

129


Bits/carrier

Carriers

23456789

1011121314

1



130


Bits/carrier

Carriers

23456789

1011121314

1



Noise margin is spread over the full spectrum

Bitswapping protects your DSL line against slowly changing line conditions

131

Reed-Solomon correction mode

Byte1234

239

k byte message vector

n byte code vector

254255

240

n - k check bytes

Code RS(255,239)

Distance : n-k+1d= 255-239+1

d=17

Correction: (d-1)/2c=(17-1)/2

c = 8

With 16 check bytes, the RS code can correct up to 8 erroneous bytes

per code vector

Error correction overhead = 16/255 = 6.3 %

132

Reed Solomon

Message vector Ctrl

Received data

Transmitted data

Distance = 15-11+1= 5 Correction = (5-1)/2= 2

More than 2 lost bytes

Burst of errors

Data to be transmitted

Lost data

133

Interleaving

Message vector Ctrl Data to be transmitted

Transmitted Data

Bloc 0 Bloc 1 Bloc 2

Received Data

CtrlCorrection CtrlCorrection CtrlCorrection CtrlCorrection CtrlCorrection

Bloc 3 Bloc 4

Bloc 0 Bloc 1 Bloc 2 Bloc 3

Burst errors

6 lost bytes

1 Byte errorper bloc!

134

ADSL superframe

DS 3DS 2DS 1 DS 4 DS 68DS 67. . . . . SS 69

SUPERFRAME17 ms

DMT Symbol

DMT symbol a DMT symbol is the sum of all symbols on each individual

carrier Data Symbol (DS)

a data symbol is used to transmit payload information Synchronization Symbol (SS)

a synchronization symbol is transmitted after 68 data symbols to assure synchronization and to detect possible loss of frame

ADSL symbol period Ts=17ms/69 = 246,377 s Ts=17ms/68 = 250 s (symbol period for the data plane)

135

Trellis coding

Trellis coding is another error detection and correction mechanism which is optional for ADSL.

Trellis principle looking at the complete data, you’re able to detect and

correct errors, similar to detection and correction is spoken language.

Example :transmitted data the water is wet and coldreceived data the water is llet and cold

by looking at the word “let” only, we can not decide that the sentence is wrong.

by looking at the information before and after the word (context), we can safely say that it should be “wet” instead of “let”.

136

ADSL & Reed Solomon

DS 3DS 2DS 1 DS 4 DS 68DS 67. . . . . SS 69

SUPERFRAME17 ms

DMT Symbol

Assume Trellis coding is NOT used ! 1 data symbol corresponds to a 255 RS word. Some bytes in the

RS word are framing overhead used for modem to modem communication (EOC, AOC, IB, CRC)

If RS is not used, our data still runs through the RS decoder. Maximum downstream ADSL speed for our data :

with RS (255-16-1)*8bits/byte*4000 symb/sec = 7,616 Mbps

without RS (255-1)*8bits/byte*4000 symb/sec = 8,128 Mbps Currently, more than 1 RS word can be mapped to 1 DMT

symbol. Rates higher than 8,1 Mbps are possible

137

Coding gain

Bits/symbol QAM uncoded Trellis RS Trellis + RS4 QAM-16 21,5 16 17,5 12,56 QAM-64 27,5 22 23,5 18,5

SNR for BER = 1E-7

From the table QAM vs. SNR, we have seen that to attain a BER of 10-7 for a specific QAM you need a certain SNR.

if the SNR is lower than this value, the BER will be too high. by introducing error detection and correction you lower the BER

because a number of the introduced errors will be corrected. The mechanism introduces a coding gain resulting in an

actual lower SNR that is needed to achieve a certain constellation.

Trellis introduces a brute coding gain of approximately 5,5dB RS introduces a brute coding gain of approximately 4dB Trellis & RS together introduce a brute gain of approximately

9dB

138

Data rate terminology

Net Data Rate (NDR) Rate at input of the PMS-TC layer (alfa/beta interface) sometimes referred to as the payload rate

OverHead data rate (OH) Sum of OAM data (e.g. EOC) and CRC bytes

Aggregate Data Rate (ADR) net data rate + overhead data rate Rate at input of RS encoder (A-interface)

Total Data Rate (TDR) aggregate data rate + RS coding overhead Rate at output of RS encoder = Rate at input of Trellis encoder

(delta-itf.) Line Rate (LR)

Total data rate + Trellis coding overhead Rate at output of Trellis encoder (U-interface) LR = ( sum of b(i) ) * symbol rate

139

Data rate terminology

Graphical Representation

bearer data + OAM + CRC

+ FEC overhead + Trellis bits

PMDPMS-TCPMS-TC

net data rate

(alpha-beta interface)

aggregate data rate

(A-interface)

total data rate (delta-interface)

line rate (U-interface)

NDR ADR

TDR Line rate

FEC overhead

application specificdata

TPS-TC

140

Impulse Noise Protection (INP) in ADSL2(+)

Impulse noise protection How much of the DMT symbol is protected? Protection via Reed Solomon and extended via interleaving

Which parameters influence the INP S = # DMT symbols per RS word D = interleaving depth (# of combined RS words used) N = Number of bytes per RS word (1 255 bytes) R = Number of RS overhead bytes (0 16 bytes)

(ms)delay 4

DS

NRDS0,5INP

141

Step 1: protection for 1RS / 1DMT symbol

NO interleaving introduced R=overhead bytes N=Total bytes K= payload bytes Correction on payload = R/2

What part of the DMT symbol is protected? Number of correctable bytes over number of bytes in DMT

symbol INP = DMT protection = payload correction / N = R / (2xN)

K R

DMT symbol

142

Assume 1 RS word / 4 DMT symbols & NO interleaving S = # DMT symbols per RS word = 4 We have seen before that RS correction = R/2

How much of the DMT symbol is protected? RS word is now spread over 4 DMT symbols

With R=16 you have 8 correctable bytes over 4 DMT symbols

INP = (# correctable bytes) / (#bytes in a DMT symbol)= = (R/2) / (N/S) = (S x R) /( 2 x N)

INP increases with a factor S

Step 2: protection for 1RS / S DMT symbols

DMT DMT

RS

DMT DMT

143

...

1 2 3 4 5 6

Step 3: introducing interleaving

Correction has improved by a factor D Errorred bytes are spread over “D” RS words Payload correction = D x R/2

DMT protection has as such also increased = # correctable bytes / N = (DxR)/(2xN)

BufferD

D = interleaving depthN = number of bytes per RS word

incoming

outgoing

Max. 255 Bytes

..

N

B1B1B1B1B2B2B2B2 BxBxBxBx Bz Bz BN BN BN BN...

Assume 1 interleaved RS word / DMT symbol

Size N

Max. 64

144

Step 4: all together

RS introduces a correction = R/2 RS correction presented by parameter R

Interleaving introduces an improvement on the number of correctable bytes

Interleaving represented by parameter D

S factor introduces an impact on the number of correctable bytes per DMT symbol

INP = (S x # correctable bytes) / N = S x R x D / (2 x N)

145

conclusions

INP = S x D x R / 2 x N How to increase the INP

Increase S > increases the introduced delay Increase D > increases the introduced delay Increase R > Decreases the available bitrate Decrease N > Decreases the available bitrate

When configuring a DSL port a max delay needs to be given and a minimum INP

This will impact the max. possible bitrate

Available Net data rate ≈ 32 kbps x (N-R) / S

146

Impact of INP/delay on performance When

Higher Minimum INP is required Lower Maximum delay is required

Rate will decrease Decrease of Efficiency on all datarates

Due to more coding overhead Decrease of Max Possible Net Datarates

decrease of “ceiling” on rate-reach curveDue to framing / coding Limitations

– TX limitations due to standard – RX limitations due to standard and chipset

But Performance might increase ! Performance is more than raw datarate only ! Due to lower BER, throughput might increase

Remark: increase only when impulse noise is really present

ceiling

efficiency

NetDatarate

Reach

ceiling

efficiency

NetDatarate

Total Datarate

147

Impact of INP/delay on performance

Decrease of Efficiency (on all rates) Terminology

Efficiency = Net Datarate / Total Datarate– Net Datarate = without RSOH– Total Datarate = with RSOH– RSOH = Reed Solomon Overhead

Efficiency = 1 – Percentage RSOH

Approximate FormulaPercentage RSOH = max ( 6.25, INP/(2*Delay) ) %

– Note : Delay in [ms], INP in symbol.Percentage Rate_loss = Percentage RSOH – 6.25

– 6.25 % = RSOH already needed for “normal” coding gainZero Loss when : Delay >= 8 * INP

148

Figure 1 :

Net

Dat

arat

e (b

ps)

Total Data Rate (bits/symbol) x 4000 symbols/sec = bps

D=384D=511D=384D=511

D=384D=511

D=384D=511

ADSL2+ADSL2+

149

Figure 2 :

x 4000 symbols/sec = bps

D=384D=511D=384D=511

D=384D=511

D=511D=384

D=511

D=384

ADSL2+ADSL2+

Total Data Rate (bits/symbol)

Net

Dat

arat

e (b

ps)

150

Figure 3 :

x 4000 symbols/sec = bps

ADSL2+ADSL2+

Total Data Rate (bits/symbol)

Net

Dat

arat

e (b

ps)

151

Rate adaptation mode: operator controlled

The modems will synchronize to a line rate which is capable to support the operator set “planned bitrate” if the attainable line rate is planned bitrate

If the modems are not able to achieve the planned bit rate they will not synchronize and an alarm is generated

kbits/s

Planned bitrate = 500 kbits/s

512kbits/sActual rate

152

Rate adaptation mode: automatic (ADSL2 with SRA)

modems synchronize between a set minimum and maximum online adaptation to degrading or improving line conditions If the modems can’t synchronize, an alarm is generated.

kbits/s

MaxLR

MLR

ALR

t

Reset

threshold bit rate

153

Some examples of ‘new’ annexes: Annex I, J and M

UPAnnex A

UP

1.1 MHz

POTS

Annex B

Annex I

Annex J

Annex M

ISD

NPO

TSDOWN

138kHz

UP

UP

UP

UP

DOWN

DOWN

DOWN

DOWN

120kHz 276kHz

All digital

154

ADSL2+ doubles the frequency spectrum

155

Reach Extended ADSL2 concept

Same or even less total Tx power On long loops (e.g. up to 5.5 km 26 AWG) Increase in reach of 300-600m (26 AWG, 0.4mm loop) New ADSL2 PSD mask with reduced crosstalk to other

DSL services. Leads to a small reach increase on the longest loop of

about 0,5 kft relative to ADSL2, if SHDSL is a dominating crosstalker.

In self-crosstalk the length increases up to 600m.

using a higher power level (PSD) in a smaller band

156

READSL2: PSD masks

2 modes defined Non overlapped Overlapped: optional (not implemented)

2 Upstream PSD masks Higher PSD level in narrower frequency band. Same total power

1 Downstream PSD mask Boosted PSD level over half the bandwidth. Same total power

PSD(dBm/Hz)

6 14 24 32 128 255

-32,9-36,4-38,0

-37,0

carrier

-40,0

mode 1mode 2

157

VDSL2 Band plans - ETSI

Band plans 998 and 997 + Variants Accommodate POTS & ISDN overlay Different US0 types

A: “normal US0” (25-138 kHz) M: “extended US0” (25-276 kHz) B: “shifted US0” (120-276 kHz)“No US0" (f0 = N/A)

f0L f0H f1 f2 f3 f4 f5=12

TBD f [MHz]

US0 DS1 US1 DS2 US2

Band plan

Band-edge frequencies (As defined in the generic band plan

Figure 7-1) f0L f0H f1 f2 f3 f4 f5 kHz kHz kHz kHz kHz kHz kHz

25 138 138 997 25

276

276

3000 5100 7050 12000

25 138 138

25 276 276

120 276 276 998

N/A N/A 138

3750 5200 8500 12000

158

VDSL spectrum - ETSI

ISDNPOTS f

DMT

138 kHz 1.1MHz 12MHzoptional upstream band downstream band upstream band

~25 kHz

Plan 997– optimized for optimized for symmetrysymmetrydown up updown

0.138..0.276 3.0 5.1 7.05 12.0 MHz

down up updown

3.75 5.2 8.5 12.0 MHz

ADSL

0.138 1.1 MHz

Plan 998 - optimized for asymmetryasymmetry

f1f0 f2 f3 f4 f5

0.138..0.276

159

VDSL2 amendment, bandplan for region B, ETSI (jan.07)

f0L f0HkHz kHz

A 25 138M 25 276A 25 138

997E30

A 25 138M 25 276B 120 276

A 25 138B 120 276

HPE17HPE30 30000

US4

US3

US4176647050 10125 12000 14000 21450 24890

US0 DS1 US1 DS2 US2 DS3 DS4998ADE30 30000

176645200

US3

DS2

DS3

8500 12000

138

3750

276

997

998E30

998E17

997E17

998

24890

DS4US2

24890DS3US2

US3

US0 DS1 US1

998ADE17 276276138

bandplan

DS1 US1 DS2

f2kHz

f1kHz

US0 type

30000

US4DS3 US3 DS4

19500 2700017664

f9kHz

14000

f3 f4 f5 f6 f7 f8kHz

276

kHz

12000

US1 DS2DS1

138

kHz

138

kHz kHz kHzUS2

5200 8500

3000 5100 7050

138

276138

US0138

138138

US0

30000

12000

276

1400017664

21450276

138276

3750

160

Noise margin parameters

SNR (dB)

SNR needed for the configured line rateS0

NM (dB)

t (s)

SNR measured at startup (Pmax)

6dBTARGET NOISE MARGIN(TNM)

MAX. ADD. NOISE MARGIN(MANM)

S2 = SNR needed for startup

= S0 + TNM

S2

S1

S1 = SNR for max. output power at startup

S3 = SNR AT startup = S2 + MANM

S3

MINIMUM NOISE MARGIN(MinNM)

Adjust output power

!>1’: RESET

STARTUP SHOWTIME

MAX. NOISE MARGIN(MaxNM)

Documents

5530NA Hanoi Training.ppt