wdm sytem troubleshooting issue1.3

8/10/2019 WDM Sytem Troubleshooting ISSUE1.3

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Optical Network Curriculum

Development Section

ISSUE

OTC000301 DWDM SystemTroubleshooting

1.3


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1Confidential Information of Huawei.No Spreading without Permission. Security Level: Internal

1.Basic methods of fault localization

2.Classification of fault processing


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Requirements for Maintenance Personnel

Familiar system signal flow

Knowing well about hardware configuration

Collecting and storing the data during normalrunning situation

Collecting and storing the on-site data (when

faulty)


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Basic Thoughts

The key step is to locate the fault to acertain cable or a station or a exactboard accurately.

Why Trouble


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Basic Principles

Locate the fault:From external to internal

From wavelength adding &dropping sites to middle

sites ,and then to specific sub-rackAnalyze alarms from high level to low level


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Common Methods

1. Alarm and Performance Data Analyzing

2. Testing With Instruments

3. Replacement

4. Loop-back Method

5. Experienced Processing Method


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A B

S D H TWC

RWC

M32/M40

D32/D40

WBA

WPA

WPA

WBA

D32/D40

M32/M40 S D H

TWC

RWC

One of the channel f rom A to B i s inter rupted !

How can we

locate the fault

S D H

TWC

RWC

S D H

TWC

RWC

Alarm and Performance Data Analyzing


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1. Optical spectrum analyzing (wavelength ,optical

power ,OSNR)

2. Optical power meter ,SDH analyzer

3. If possible ,compare power from performance in

NMS with power from instrument

4. MON port is available for on-line test

Testing With Instruments


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S D H

A

B

TWC

RWC

Alarm: LWC/TWC/OCU R_LOS

Measure receiving power of LWC/TWC/OCU .

Check Tx of SDH ,and patch cord betweenSDH&OTU ,Rx of OTU


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Replacement Method

1. Board (OTU ,OA) 2. Fiber3. Connector4. Modules5.


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S D H

A

B

TWC

RWC

S D H

C

D

TWC

RWC

Exchange thereceiving signal of twoTWC,then observethem.

Alarm: TWC RLOS


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If there is still R-LOS,

Rx of TWC?

If there is R-LOS alarm on the

other TWC,Tx of SDH ?Patch cord?

S D H

A B

TWC

RWC

S D H

C

D

TWC

RWC


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Loopback Method

Tx1

Tx2

Txn Rxn

Rx2

Rx1OM/OA

Rx1

Rx2

Rxn Txn

Tx2

Tx1OLA OM/OA

OA/OD

OLA

OA/ODattenuator

attenuator

SDH

Analyzer


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Loopback Method

S

D

H

S

D

H

TWC M32 WBA WPA D32

M32WBAWPAD32RWC

RWC

TWC

RWC

TWC

TWC

RWC

RWC repor ts RLOF alarm ,TWC is normal


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Experienced Processing Method

Reset board

Plugging/unplug board

Re-send configuration (SCC replacement)

It i s recom m end ed to u se th i s method asless as po ss ib le , s ince i t i s u nsu i tab le forf ind ing fau l t reason thoro ugh ly.


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Classification of fault

1. NMS problems 2. Optical power problems

3. Error problems 4. Service interruption

5. Ecc problems 6. Order wire problem

7. Equipment interconnection problem

8.Other problems


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Cases:SQL SERVER 7 is not started----

computer name is changed

User already logined---

Create different user names

Backup failed- ---

Unix:% /T2000/server/database/backupmo.batT2000%tar cvf mo_bak_XXXX.tar mo

PC:C:\T2000\server\database\Backupmo.batto \T2000\Server\database\mo


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2.Optical power problems

Common Causes :

Fiber or patch cord is deteriorated or too tight

Tx or Rx module of accessed equipment is faulty.

Tx or Rx module of OTU is faulty

OA is faulty

Optical components are deteriorated.


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Common Methods:

Alarm and performance analyzing

Power adjustment

Instrument testing

Loopback

Replacement

Famil iar w i th the op t ical po wer sp ec i fica t ion of

OTU ,OA ,M32 ,D32 etc ,.

Optical power problems


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S

D

H

S

DH

TWC M32 WBA WPA D32

M32WBAWPAD32RWC

A B

RWC

TWC

RWC

TWC

TWC

RWC

IN-PWR-LOW alarm is

detected ?


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The col lec ted perform ance data atdifferent t im e are l is ted below.

What happ ened?

S

D

H

S

D

H

TWC M32 WBA WBA WPA D32 RWC

TWCM32WBAWPAWBAWPAD32RWC

A B C


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BoardWPA

in

WPA

out

WBA

in

WBA

out

A

From B -15.6 7.0

To

B

-9.2 14

B

FromC

-14.6 7.8

To

C

C

From

B

-14.3 7.6

To

B

-9.0 14.4

Board

WPA

in

WPA

out

WBA

in

WBA

out

A

From

B

-20 -3.4

To

B

-9.2 14

B

From

C

-19.6 3.2

To

C

C

From

B

-14.3 7.6

To

B

-9.0 14.4

Firs t t ime Seco nd t im e


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3. Error problems

Common Causes :SDH Tx or Rx is wrong

Power is too high or too low ,Attenuation

Dispersion limitation

OSNR too low-------signal power is too low ornoise is too serious

Tx or Rx of OTU board

OA is faulty--------pump?FEC function is faulty

E bl


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Error problems

Common Methods:

Alarm analyzing

Error performance monitoring

Instrument test

Power adjustment

Replacement method (board ,patch cord)

..

E bl


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S

D

H

S

D

H

TWC M32/M40 WBA WPA WBA WPA D32/D40 RWC

TWC M32/D40 WBA WPA WBA WPA D32/D40 RWC

A B C

Bit errors are generated in services from A to C.

Error problems


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4.Service interruption problems

Common Causes :Optical line cable is faulty or patch cord is notwell connected

Board is fault

Rx of OTU is unstable

Tx of OTU is faulty


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Service interruption problems

Common Methods:Analyze the faulty direction ,status of OSC channel andmain channel , number of faulty wavelength channel

Alarm analyzing and performance monitoring

Instrument test (on-line measurement)

Power adjustment

Replacement method (board ,patch cord)

..


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Service interruption problems

2 3

O

TM

O

L A

O

TM

1

100Km 90Km

RLOS i s d etected in

OTU at receiver sid e ?


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5. Ecc problems

Common Causes :Power supply is faulty

SCC unit fault

SC1 or SC2 board faultHUB problem network cable connection

Fiber connection

ID or IP problemsECC channel is blocked.

Ecc problems


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Ecc problems

Common Methods:

Alarm and performance analyzing method.

Reset SCC board.

Replacement method

..

ECC bl


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ECC problems

Station A can not login station B and C normally.

NMS

A CB

ECC bl


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ECC problems

After replacement of SCC board at station B ,

It is found station A and B can be logined normally,but station C cannot.

NMS

A CB

6 Order wire problem


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6. Order wire problem

Common Causes:

External factors -- such as power failure, brokenfiber and so on.

Wrong setting of telephone set .

Wrong OHP configuration data.

Board faults -- such as SC1, SC2 and OHP.

Order wire problem


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Order wire problem

Common Methods:

Alarm and performance analyzingReplacement method


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Order wire problems AThe order wire from A to B and C isblocked, even stations B and C can notbe called by dialing the conferencetelephone from station A.


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7. Equipment Interconnection

WPA D32/D40 RWC

RWF

M32/M40 WBA

M32/M40 WBA

WPA D32/M40

TWC

TWC

RWC

RWC

TWC

TWC

A B

SDH-1

SDH-2

SDH-1

SDH-2

The services from A and B are blocked.


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8. Other problems

Accessing signal is not standard

Pointer adjustment

Special unit is faulty (VOA ,flange ,connectors)Instrument testing ( test method is wrong)

Label is wrong

HUB is faulty


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wdm sytem troubleshooting issue1.3

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