part 4 - bsc6900 uo troubleshooting flow introduction issue 1.00

8/6/2019 Part 4 - BSC6900 UO Troubleshooting Flow Introduction ISSUE 1.00

1/43

Course Name

Confidential Information of Huawei. No Spreading Without Permission

P-1


2/43

Course Name


P-2


3/43

Course Name


P-3


4/43

Course Name


P-4


5/43

Course Name


P-5


6/43

Course Name


P-6

Knowledge about telecommunications, including the principles of WCDMA system.

Product knowledge, including RAN data configuration, RAN hardware structure, RAN

operation and maintenance, etc.

Related signaling and protocols, including interface protocols, etc.

Related international technical specifications.

PC network fundamentals, including Ethernet, TCP/IP, Client/Server, database, etc.


7/43

Course Name


P-7


8/43

Course Name


P-8

Which operations may cause interruption over part or all of the traffics.

Which operations may cause equipment damage.

Which operations may cause subscriber complaints.


9/43

Course Name


P-9


10/43

Course Name


P-10


11/43

Course Name


P-11

Information collection: The failure information that needs to be collected before

the troubleshooting.

Fault judgement: The location of fault area and type. After collecting the fault

information, you need to analyze fault symptoms to determine the fault area

and type.

Fault location: The fault cause location by analyzing and comparing possible

causes.

Fault removing: After locating the fault, you need to remove the fault.


12/43

Course Name


P-12

Collecting fault information in the following ways:

Consult the person who reports the fault about the symptom, time, location,

and frequency of the fault.

Ask the operator of the equipment about the daily running status, failure

symptom, operations performed before the fault occurs, and measures taken

after the fault occurs and the consequence.

Observe board LEDs and the alarm management system on the LMT to obtain

information about the running status of software and hardware.

Test the service, measure the performance data, or trace interfaces or

signaling messages to learn the scope of the fault and the impact of the fault

on the system.


13/43

Course Name


P-13

During RAN routine maintenance, most fault information is from the former three

sources. However, usually the initially obtained fault information cannot describe the

trouble completely and thoroughly, especially when the information is got via a phonecall. The information cannot represent the essence of the fault unless it is given in

detail.

Nowadays, the network size is growing and the complication of networking is

increasing. The change in and interference from the various internal and external

factors may constitute a negative impact on the normal running of RAN. Consequently

RAN faults might result from some more complex causes. This makes it more and

more difficult to locate a RAN fault.

It is no use to just analyze the problem and try to solve it based on the inadequate

information. It may enlarge the scope of faults to be located and increase the difficulty

of solving them, even lead to the error processing methods, thus losing the bestchance to remove the faults. So, it is essential to collect various original information.


14/43

Course Name


P-14

During implementation or expansion, we can Interchange NodeBs and judge

whether the fault is subject to RNC or NodeB.

During maintenance, RNC faults do affect some or all of NodeBs.


15/43

Course Name


P-15

Link Fault: E1T1, FE/GE, Optical cable, signaling link fault.

Clock Fault: Abnormal clock makes voice quality and the transmission of data

services maybe affected.

Handover Fault: If the handover fails, the service quality is deteriorated or the call is

dropped.

Access Fault: When an access fault occurs, the UE cannot receive radio signals or

register with the network, the UE drops the call frequently, or the UE cannot make

calls or be called after the registration.

CS Service Fault: When a CS service fault occurs, the UE cannot make phone call, or

has low quality of CS service.

PS Service Fault: When a PS service fault occurs, the UE cannot access the GPRS

network or the UE cannot obtain corresponding PS services although it can accessthe GPRS network.

Cell Fault: Cell fault refers to cell setup fault.

O&M Fault: O&M fault make O&M for RNC and NodeB unavailable.


16/43

Course Name


P-16

As mentioned in the above, although there are many factors for the fault of the RAN,

they seldom function simultaneously. That is, only some or one of them function at the

specified time.

The fault location is to exclude the impossible causes and find the right ones from

many possible causes.

The accurate and fast location can not only improve the troubleshooting efficiency but

also avoid the man-made accidents caused by the error operation.


17/43

Course Name


P-17


18/43

Course Name


P-18


19/43

Course Name


P-19

After locating the fault, you can start to remove the fault and restore the system by

taking proper measures, such as checking the cables, replacing the faulty boards,

modifying configuration data, switching over a pair of active and standby parts, andresetting the boards.

When removing the fault, ensure that:

Use different procedures for different faults.

Check the system again after the troubleshooting to ensure that the fault is

completely removed.

To avoid the occurrence of similar faults, record the causes of the fault and

take preventive or corrective measures.


20/43

Course Name


P-20


21/43

Course Name


P-21


22/43


23/43

Course Name


P-23

The RAN maintenance personnel usually can get more than what they expect if they

do well in collecting the original information and analyzing it effectively and thoroughly.

Besides handling the UE related trouble, the original information analysis can also be

used to handle other troubles, especially the trunk trouble. Trunk is related to

transmission system interconnection and signaling matching, therefore, the original

information collection seems to be vital to trunk troubleshooting. Such original

information includes the operating status (normal or not) of transmission system, state

(modified or not) of data at the peer office, definitions of some signaling parameters,

etc.


24/43

Course Name


P-24

Log File Type:

GUI Value Range: PFM_RESULT(Performance result file),

HOST_PFM_RESULT(Performance result file from host),

ACTIVE_DEF_MEAS_FILE(Active default measurement task file),

STANDBY_DEF_MEAS_FILE(Standby default measurement task file),

PFM_SWITCHS(The switchs information for performance),

HISTORY_ALARM(History alarm file), HISTORY_FAULT(History fault file),

ALM_SYSTEM_CFG(The configured information of alarm),

SECURITY_LOG(Security logs), OPT_LOG(Operation logs), OMU_LOG(The log

information of OMU), BSC_CFG_MML(The data configure file of the BSC),

CELL_BASIC_INFO(The basic information of cells), BSC_SERIES_NO(The series

No. of the BSC), DB_BAK(The backup file of the database), MEM_DB_BAK(The

backup file of the database in memory), BTS_BASIC_INFO(The basic information ofsites), BTS_CHECK_LOG(The examination file of BTS), BTS_DEBUG_LOG(The

debug file of BTS), BTS_CHR_LOG(The CHR log of BTS), TRX_LOG(The TRX log),

BTS_NET_TABLE(The net table information of BTS), DEBUG_LOG(The common

debug log), LAST_WORD(The last word log), DSP_DEBUG_LOG(The debug log of

DSP), HOST_LOG(The running log of the host), 2G_CHR_LOG(The CHR log for

GSM), 3G_CHR_LOG(The CHR log for UMTS), 2G_UNILATERAL_CONNECT(The

unilateral connection log for GSM), BSC_INFO(The basic information of the BSC),

GCSR_LOG(The CHR log for single user of GSM CS), GPSR_LOG(The CHR log for

single user of GSM PS), AIDG_LOG(A interface dial diagnose log), BIOS_LOG(BIOS

log)


25/43

Course Name


P-25

The alarm information output from the alarm maintenance system includes the

detailed description of the abnormality, possible causes and restoration suggestions.

It involves the hardware, link, trunk and CPU loading ratio, etc., with abundant andcomplete information. It is a gist for the fault analysis and location.

The alarm information analysis is mainly used to find the specified section or cause of

the fault. Due to its abundant contents, the alarm information may be used to locate

the fault cause itself or along with other methods. It is one of the main methods for

fault analysis.


26/43

Course Name


P-26


27/43

Course Name


P-27


28/43

Course Name


P-28


29/43

Course Name


P-29

Due to the inadequacy of the information indicated by the indicators, they are

generally used along with the alarm information.

An LED reflects the working status of a board, a circuit, a link, an optical path, or a

node. The LED is an important key to fault analysis and location.

The LED status is used to quickly locate the fault and the causes of the fault. Because

of limited information, the LED status is often used together with alarm information.


30/43

Course Name


P-30


31/43

Course Name


P-31

A Calling test is used to check the call processing function of the RAN and the

relevant equipment. It is a simple and quick way of troubleshooting.

Calling tests are often used in daily maintenance to determine whether the UE,

NodeB, RNC, and trunk system work properly. Calling tests are also used together

with continuous and dynamic tracing to test the RAN functions.


32/43

Course Name


P-32

Measurement is a common technical means of RAN troubleshooting. It is widely used

in power supply testing, signaling analysis, waveform analysis, and bit error rate (BER)

check. Through instruments and meters, you can directly obtain fault-related data.


33/43

Course Name


P-33

Performance statistics is a means of analyzing the call drop rate.

The call drop rate is an important counter of the RAN. It is affected by many factors

and therefore difficult to predict. Performance statistics can help to find call drop

causes in time and prevent call drops effectively.


34/43

Course Name


P-34

The interface trace is applied in locating the failure causes of subscriber call

connection and inter-office signaling cooperation, etc. The trace result can help to find

the cause of call failure directly and locate the problem or to get the index for thesubsequent analysis


35/43

Course Name


P-35

A loopback test refers to such a test in which a transmitted signal is returned to the

sending device. Loopback is used to observe the functioning of a device or channel,

the provisioning of services, and the status of signaling flows. With the information,you can determine whether hardware and software parameters are properly set.

Loopback is commonly used to locate transmission faults and trunk parameter errors.

During the process of setting up a new site and expanding the capacity of trunks,

loopback of a RAN trunk can help to determine whether the trunk and signaling link

parameters are properly set.

Loopback tests are usually used together to locate transmission faults.


36/43

Course Name


P-36

There are several kinds of Loopback: board port loopback, board port timeslot

loopback, Remote Speech Channel Loopback and DSP Channel/Link Loopback.

On the LMT

Board port loopback : BSC Maintenance > Maintain Transmission and

Signaling > Interface Board Port Loopback.

Board port timeslot loopback: BSC Maintenance > Maintain Transmission and

Signaling > Interface Board Port Timeslot Loopback

Remote Speech Channel Loopback :BSC Maintenance > Maintain User

Resource > Remote Speech Channel Loopback

DSP Channel/Link Loopback : BSC Maintenance > Maintenance User

Resource > DSP Channel/Link Loopback


37/43

Course Name


P-37

You can compare the symptoms of a faulty part with those of a good one to find out

the causes. Comparison is applicable when the fault occurs in a narrow scope.

You can replace the faulty part with a good one to compare the running status of the

two parts to determine the scope or location of the fault. Interchange is applicable

when the fault occurs in a wide scope.


38/43

Course Name


P-38

The switching and resetting can not locate the fault cause accurately, and due to the

randomness of software running, the fault may be not able to re-occur after the

switching or resetting, thus it is difficult to know the real fault and solve the problem.So, this method is just an emergency method, applicable only in the emergent

situation:

Compared with other methods, switchover and reset are auxiliary methods.

After switchover or reset, the fault symptom seldom appears again within a

short period.

As a result, the faults cannot be found, which brings potential security and

stability risks to the equipment.

Usually, the reset operation disrupts the ongoing services and even brings the

system down.


39/43

Course Name


P-39


40/43

Course Name


P-40


41/43

Course Name


P-41


42/43

Course Name


P-42


43/43

Course Name P-43

part 4 - bsc6900 uo troubleshooting flow introduction issue 1.00

Documents