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OptiX RTN 600 Troubleshooting
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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
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1. Troubleshooting Preparation
2. Troubleshooting Idea and Methods
3. Classified Troubleshooting Examples
Content
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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
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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
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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.
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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
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1. Troubleshooting Preparation
2. Troubleshooting Idea and Methods
3. Classified Troubleshooting Examples
Content
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One question
What is the key for troubleshooting ?
To locate a failure ACCURATELY in one station
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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
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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
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Common Methods of Fault Locating Alarm and performance analysis
Loopback
Replacement
Configuration data analysis
Configuration modification
Test with instruments
Rule of thumb
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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
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Obtain alarm and
performance events
Select the key alarm or
performance events
Analyze reasonsLimit the troubles to a
certain range or a node
Alarm and Performance Analysis
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R-LOF
1 2 3
MW-RDI
HSB-INDI
Alarm and Performance Analysis
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.
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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.
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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.
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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
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Procedures
Draw the traffic flow diagram
Loopback section after section to locate the faulty NE
Locate the faults to certain boards
Loopback
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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
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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
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Port
Timesl
ot
Slot
No spare No spare
boardsboards
Restore the Restore the
traffic traffic
temporarilytemporarily
Objective Application Examples
Configuration Modification
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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
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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.
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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.
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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
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Contents
1. Troubleshooting Preparation
2. Troubleshooting Idea and Methods
3. Classified Troubleshooting Examples
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Classified Troubleshooting Examples Traffic Interruption
Wrong configuration
Bit Errors
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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
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Traffic Interruption
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
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Traffic Interruption
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
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Traffic Interruption
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 ;
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Classified Troubleshooting Examples Traffic Interruption
Wrong configuration
Bit Errors
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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.
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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
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Classified Troubleshooting Examples Traffic Interruption
Wrong configuration
Bit Errors
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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
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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.
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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.
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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
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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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