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OptiX RTN 600 Troubleshooting


Objectives Upon completion of this course, you will be able

to:

List the common analysis methods of fault locating

Outline the Fault Handling Flow

Analyze the typical faults: traffic interruption, error bit, etc


1. Troubleshooting Preparation

2. Troubleshooting Idea and Methods

3. Classified Troubleshooting Examples

Content


Be familiar with hardware system and Digital

Microwave Communication principle, particularly

in the alarm signal flow

Alarm/performance generation principle

Master the basic operations of the transmission

equipment

NMS, testing devices, loopback, board

replacement

Requirements for Maintenance Personnel


Requirements for Maintenance Personnel

Familiar with the network under maintenance

Network topology, network protection, traffic

configuration

Collect and save on-site data

System alarms, performance events data,

configurations, operation records of NMS


Flow ChartStart

On site or not

Hardware problems?

NO

YES

NO

YES

If the fault does not affect the network

element access, query the alarm and follow the

“maintenance manual” ;If problems cannot be solved

through the above methods or remote access is not permitted., please deal with the problems

on site.water flowing or fire? If all indicators

off, check the PXC board power input;And then check the SCC board

indicators status.


Flow Chart

Query alarms

Transfer to SDH process

YES

NO

Please replace the corresponding board if report

the alarm below: A_LOC, DBMS_PROTECT_MODE,

HARD_BAD, POWER_ALM, POWER_FAIL, RADIO_TSL_HIGH,

RADIO_TSL_LOW, RP_LOC, T_F_RST , T_FIFO_E, R_F_RST.

Follow the “maintenance manual” to handle the alarms

below ： APS_MANU_STOP, ALM_RTC_FAIL, APS_FAIL,

BD_NOT_INSTALLED, R_LOS,R_LOF,CONFIG_NOSUPPORT,RADIO_MUTE,RADIO_RSL_LO

W,MW_LOF,MW_LIM





Content


One question

What is the key for troubleshooting ?

To locate a failure ACCURATELY in one station


External first, then internal

Exclude external problems first

− IF cable, switch failure

−Power failure, grounding

Station first, then boards

Try your best to locate the troubles to one node

Basic Principles for Locating Faults


Basic Principles for Locating Faults Microwave side first, then SDH side

First check the Microwave side problems

Higher-severity alarms first, then Lower-severity alarms

First analyze critical/major alarms

Then come to minor/warning alarms


Common Methods of Fault Locating Alarm and performance analysis

Loopback

Replacement

Configuration data analysis

Configuration modification

Test with instruments

Rule of thumb


Use NMS How to obtain alarms and performance?

Observe indicators on boards and cabinets

•Not detailed•No history alarms

•Comprehensive•All alarms/performance events from the whole network

•Accurate• Current alarms, history alarms, occurrence time and performance event data can be queried.

Alarm and Performance Analysis


Obtain alarm and

performance events

Select the key alarm or

performance events

Analyze reasonsLimit the troubles to a

certain range or a node



R-LOF

1 2 3

MW-RDI

HSB-INDI


Description

NE1 & NE2 is STM-1 capacity 1+1 configuration;

After switching, that was an alarm “R_LOF" on NE1;

Alarm "MW_RDI", “HSB_INDI” on NE2.


Alarm and Performance Analysis Possible reasons:

Second ODU is faulty;

IF-board is faulty;

TX/RX Frequencies of the second (protection) ODU are different from the other three ODUs on this hop;

Hybrid Coupler is faulty;

There is water in hybrid coupler;

IF-Jumper is faulty;

IF-board is faulty.


Line RTN equipment Line

Inloop Inloop

Inloop

outloop outloop

outloop

Tributary

Loopback

What is loopback?

Loopback is the most common, most efficient method in troubleshooting.


Board involved

Loopback options

Loopback tools

Loopback level

Application

Tributary board

Inloop/

outloop

Loopback cable, NMS

Loopback at path level

Separate switching faults from transmission faults. Determine the tributary board failure roughly. Be unnecessary to modify service configuration.

Line board

Inloop/

outloop

Patch fiber, NMS

Loopback by optical interface

Locate single station faults. Roughly determines the line board failure. Be no need to modify service configuration

IF/RF port

Inloop/

outloop NMS

Loopback by the IF/RF

port

the ODU supports RF port inloops and IF port inloops/outloops, separate the faults in the IFunits or the ODUMay interrupt the traffic and ECC

Software loopback is not a thorough methodWill automatically be removed in 5 minutes (provisionable)

Notes

Loopback


Procedures

Draw the traffic flow diagram

Loopback section after section to locate the faulty NE

Locate the faults to certain boards

Loopback


Replacement

Effective thoughts

MSP switch

SNCP switch

1+1 SD/FD switch

1+1 HSB switch

Objective

Fiber

Cable

Module

Board

Application

External faults

Boards faults


Query & Analyze the configuration Timeslot configuration

J1 or C2 bytes

LU 、 TU 、 IF unit or ODU loopback

SNCP or MSP switching conditions (e.g. MS-SD)

External commands (e.g. locked switch)

The consistency of the frequency between two

nodes

The appropriate transmission power of the ODU

Configuration Data Analysis


Port

Timesl

ot

Slot

No spare No spare

boardsboards

Restore the Restore the

traffic traffic

temporarilytemporarily

Objective Application Examples

Configuration Modification


Instrument Test item

Bit error testing device Bit error/traffic

Optical power meter Optical power

SDH analyzer Bit error/traffic/overhead bytes ……

Multi-meter Voltage/current/resistance

This method is the most authoritative, but we must have the devices in hand.

Testing Instrument


Rule of Thumb

Reset board

Power off and on

Resend the configuration

Last resort

Do not consider them as a

panacea

They are not helpful for us to

find the cause of the failure.


Common Methods of Fault LocatingMethods Application Features

Alarm and performance

analysisUniversal

1. Evaluate the whole network situation. 2. Locate the faulty point preliminarily based on the collected data. 3. Cause no negative effect on normal services 4. Depend on the NMS

Loopback Locate the fault to a single station or board

1. Independent of alarm and performance event analysis2. Rapid and effective

Replacement Locate the fault to a

board or isolate external faults

1. Convenient 2. Require spare parts/equipment. 3. Applied with other methods

Configuration data analysis

Locate the fault to a single station or board

1. Can find the fault cause.2. Fault locating time is longer. 3. Depend on the NMS

Configuration modification

Locate the fault to a board

1. Have a high risk. 2. Depend on the NMS

Test with instruments

Isolate external faults and resolve interconnectivity

problem

1. A general method with high accuracy 2. Have certain requirements for the meters. 3. Applied with other methods

Experience Special cases1. Fast fault handling 2. High probability of mistake 3. Need experience accumulation.


Common Troubleshooting Sequence

Exclude external troubles

Switching problem?

Fiber problems?

Trunk cable?

Power supply system?

Grounding problem?

Replacement

Instrument testing

Loopback

Alarm/performance analysis

Locate troubles to one NE

Loopback

Alarm/performance analysis

Locate the troubles to one board

Replacement LoopbackAlarm/performance analysisConfiguration analysisConfiguration modification Rule of Thumb


Contents





Classified Troubleshooting Examples Traffic Interruption

Wrong configuration

Bit Errors


Description

Hardware version is V1R2, can not configure 16E1 services ( just can configure 11E1 services);

There are no other services;

The link between NE1 & NE2 was configured 1+1HSB;

Traffic Interruption

1 2

16E1

16E1



Check the license

License just can support 23 E1( 7 E1 for free) and the 1+1

HSB need the 32 E1 license capacity

Handling process

Change the license

Delete the 1+1 HSB configuration

Generate the some alarms



Handling process

Other configurations be changed ?

Check the ODU launch

frequency or the receiving

power

Use other configuration

guides

Check the configuration for

1+1HSB

YES

NO

1 2

16E1

16E1

MW-LOF LOG_OUT



Handling process

Wrong operation process to delete the 1+1 HSB

Shut down the ODU and configure the 1+1 HSB

again

Analysis: configure the 1+1HSB, both

ODUs are set unmute status; After delete

the protection configuration, both

ODUs will be disturbed each other because they have

same launch frequency and polarization ;



Wrong configuration

Bit Errors


Wrong configuration

1 2

16E1

16E1

Config_nosupport

Description

NE1 configure 1+0 protection, at the 15 GHz band, and with 16E1 PDH;

NE1 ODU remains mute though it is set to the unmute status;

NE1 ODU transmits signals at the power of -55 dBm though its launched power is set to 21 dBm;

NE1 generates the Config_nosupport alarm.


Wrong configuration

The launched power of ODU is out of the range?

Handling process

The transmit frequency of ODU is out of the range?

The range is -6 to 24dbm, and the launched power is 21

dbm;

The range is 15GHZ band, and the actual frequency is

1.46655 GHZ

The designed frequency is 14.6655 GHZ; so change the

transmit frequency to 14.6655 GHZ



Wrong configuration

Bit Errors


Bit Errors

Description

Many bit errors generate in the microwave equipment for the interval is between 15 to 25 minutes;

The services are interrupted for 5 to 8 seconds each time;

The equipment generate MW_RDI and MW_LOF alarms;

1 2

MW_RDI

MW_LOF


Bit Errors

Wrong configuration?

Handling process

Query the alarms

Hardware problems?

Inconsistent working modes or working frequencies of the ODUs at the local and peer ends?

Yes

No

No

No

MW_RDI: When this alarm is reported, it means that the link is faulty and consequently the peer end receives error bits.

MW_LOF: The performance of the microwave link deteriorates. The receive function of the local end fails. The working modes of the ODUs in the local and peer ends are different. The working efficiency of the ODUs in the local and peer ends are different.


Bit Errors

The MW_RDI and MW_LOF alarms are related to the link

performance deterioration

a new link is created and the frequency interference occurs between the new and existing

links

After modify the receive and transmit powers of the ODUs at the local and peer ends, the problem is solved.

Handling process

Guess: other company creates a new microwave hop

and the new microwave hop

shares the site with Huawei.


Questions

What is the key of troubleshooting?

To locate a failure ACCURATELY in certain station What is the principle of troubleshooting?

External first, then internal Station first, then boards Microwave first, then SDH Higher-severity alarms first, then lower-severity

alarms


Summary Which methods for troubleshooting?

Alarm and performance analysis Loopback Replacement Configuration Data Analysis Configuration Modification Test with instruments Rule of Thumb

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