11 bsc6800 troubleshooting issue3.0

Huawei Confidential. All Rights Reserved

OWN000301 BSC6800 Troubleshooting

ISSUE3.0

2 Internal Use

This training mainly provides the

elementary ways and methods to

locate common faults of RNC

It is classified as four parts: loading

fault, Interface fault, service fault and

operation fault

3 Internal Use

Chapter 1 Troubleshooting OverviewChapter 1 Troubleshooting Overview

Chapter 2 O&M TroubleshootingChapter 2 O&M Troubleshooting

Chapter 3 Loading Troubleshooting Chapter 3 Loading Troubleshooting

Chapter 4 Interface TroubleshootingChapter 4 Interface Troubleshooting

Chapter 5 Traffic TroubleshootingChapter 5 Traffic Troubleshooting

4 Internal Use

Troubleshooting OverviewTroubleshooting Overview

General Flows of Troubleshooting Step 1: Information collection:

Information Item Collection Method

Fault symptom, as well as the time, place and frequency of the occurrence

Consult the customer service center

Daily running state of the equipment, fault symptom, operations before the fault occurrence, and measures taken afterwards

Consult the O&M staff

Software/hardware running state of the equipment

Observe the panel indicators, the BSC6800 O&M System, and the BSC6800 Alarm Management System

Scope and influence of the faultPerform service demonstration, performance measurement, and interface/signaling tracing

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General Flows of Troubleshooting Step 2: Fault Definition:

BSC6800 faults

Loading faultsLoading faults

Service faultsService faults

O&M faultsO&M faults

Cell faultsCell faults

Access faultsAccess faults

CS faultsCS faults

PS faultsPS faults

Index to

Interface link fautlsInterface link fautls

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General Flows of Troubleshooting Step 3: Fault Locating:

Loading, O&M and interface link faults are usually within narrow scopes and their causes are simple. These types of faults are announced by indicators, alarms and error prompts.

Locate the service faults in order of the BSC6800 system, interface links and cells

Step 4: Fault Clearing:

The fault clearing is the process of taking proper measures to clear the faults and recover the system, such as replacing the cables, replacing boards, updating configuration data, switching over system and resetting boards

7 Internal Use


Common Fault Location Means Alarming Interface/Protocol Message Tracing Service Demo Analysis Meter and Instrument Analysis Performance Measurement Analysis Test Analysis Comparison/Interchange Switchover/Reset

8 Internal Use


Contacting the Technical Support Engineers of Huawei

Preparations before Requesting Technical Support

Collecting Fault Information

– Full name of the office

– Contact name and telephone No.

– Time when the fault occurred

– Detailed symptom

– Host software version

– Measures taken after the occurrence of fault and their results

– Severity of the problem and the supposed time of solution

Commissioning Preparation

– Huawei engineer may suggest some operations so as to further

collect fault information or handle the fault directly

– Therefore, it is necessary to be prepared for these operations

before seeking technical support

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Contacting the Technical Support Engineers of Huawei

Huawei Contact Information

Dial the hot line of the local office of Huawei.

Customer Service Email: [email protected]

Huawei Technical Support Website:

http://support.huawei.com

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11 Internal Use

Operation and Maintenance TroubleshootingOperation and Maintenance Troubleshooting

The system consists of three

parts --O&M system, BAM

system and LMT system

The system is classified as four

modules--data management

module, maintenance

management module,

performance management

module, alarm management

module

FAM

WRSS - WRBS network

LMT LMT M2000LMT

WRSSnetwork

External network

Internal network

WRBS network

WMUXb WMUXb WMUXb

WMPU

WNETc

WLPU

WHPU

BAM

WFMRb WINTWSPUb

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General methods of BAM troubleshooting When the BAM server works normally and the startup type of each

module is “Automatic”, the interface of the Security Manager on the active BAM server is as shown

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General methods of BAM troubleshooting If some modules of the BAM software are abnormal, you can locate

faults by checking the related running logs. The running logs are in <BAM Install Dir>\Services\log

Open the debugging window of the modules to get debugging information

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The BAM Software Runs Abnormally after Adapter Driver is Reinstalled

Fault Description

The BAM software works normally after installed. However, it beco

mes abnormal after an adapter driver is reinstalled

Troubleshooting

The Ethernet adapter GUID is allocated during the installation of th

e adapter driver. It is recorded during the installation of the BAM so

ftware. When the BAM software starts, it reads this GUID and obtai

ns the IP address from the corresponding adapter.

After the adapter driver is reinstalled, the GUID will be reallocated.

However, the BAM software here still reads the old GUID. Therefor

e, it fails to find the adapter and obtain the IP address.

You need update the GUID by the BamSettingTool after the adapte

r driver is reinstalled

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The FAM and BAM Disconnect after BAM Internal Virtual IP Addresses or WMPU IP Address Is Modified Fault Description

The FAM and BAM disconnect after the internal virtual IP addresses of the BAM servers or WMPU IP address is modified

Troubleshooting

The cause is that the modification is improper

To modify the WMPU IP address

– Use SET WMPUIP command to modify WMPU IP address online

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To modify the internal virtual IP addresses of the BAM serv

ers, or at the same time modify the WMPU IP address

– Use SET WMPUIP command to modify WMPU IP addr

ess online

– Use the BamSettingTool to modify the internal virtual I

P addresses of the BAM servers, and then restart the

SecurityManager of the two servers

– Use the command DSP BRD to check the WMPU state.

If the command returns the correct IP addresses, it sh

ows that the modifications are successful.

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The Exchange Module Starts Abnormally

Fault Description

After the BAM software is installed, the startup of the excha

nge module is abnormal

Troubleshooting

Check the Load module running log lodV100R002.log in \Ser

vices\log

It is found that the file includes the information “Exception for

invalid intra-netcard IP configuration”. It shows that the intern

al IP address of the active or standby BAM server is wrong.

Use the BamSettingTool to correct the wrong. Then restart t

he SecurityManager of the active and standby BAM servers

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RNC Fault Alarms Fail to Be Recovered

Fault Description

Some faults of the RNC are cleared. However, the fault alarms are

not recovered yet

Troubleshooting

The recovery alarms are reported by the host, received and

acknowledged by the alarm module, and written in the database.

However, if the active BAM server fails during synchronization with

the standby, these alarms will fail to be copied onto the standby.

Thus, the alarms recovered on the host will still be displayed as

active alarms after switchover.

Check whether there was an emergent switchover between the two

BAM servers and whether active alarms are recovered. If so, use the

command RMV ALMFLT to recover these alarms manually

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Chapter 3 Loading TroubleshootingChapter 3 Loading Troubleshooting



20 Internal Use

Loading TroubleshootingLoading Troubleshooting

Loading principle WRSS loading

WRBS loading

BAM

TFTP

BOOTP

LoadingManagement

module

WRSSLoading

files

LoadingControl

procedure

File transferprocedure

WMPU Other boards

BAM

FTP Server

TFTP

BOOTPLoadingManagement

moduleLoading

files

Loading control procedure

File transfer procedure

FA

M b

oardFile transfer procedure

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Loading TroubleshootingLoading Troubleshooting

WRBS Works Abnormally after Interface Board Type Is

Modified

Description

The WRBS fails to process services normally after

changing the interface boards and modifying the

data with resetting WRBS

Troubleshooting

After modifying the interface board type, the operator

does not reset the WRSS. Thus, the configuration of

PVC mismatches that of the WRBS, and the WRSS

fails to process services normally

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23 Internal Use

Interface TroubleshootingInterface Troubleshooting

Iub interface Iub interface protocolprotocol

Control Plane

Transport NetworkControl Plane

User plane

RadioNetworkLayer

Q.AAL2

Transport Network User Plane

TransportNetworkLayer


NCP CCP

A B C

CCP

NBAP

SAAL UNIAAL2 PATH

ATM

Physical Layer

Q.2150.2

Q.2630.1

SAAL UNI

DC

H F

P

RA

CH

FP

FA

CH

FP

PC

H F

P

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Iu-CS interface protIu-CS interface protocolocol

Control Plane


User plane

RadioNetworkLayer

Q.AAL2




A B C

RANAP

AAL2 PATH

ATM

Physical Layer

Q.2150.1

Q.2630.1

SAAL UNI

SCCP

MTP3-B

A

Iu UP

SAAL UNI

MTP3-BB

25 Internal Use


Iu-PS interface protIu-PS interface protocolocol

Control Plane


User plane

RadioNetworkLayer




A C

RANAP

ATM

SAAL UNI

SCCP

MTP3-B

A

Iu UP

B

AAL Type 5

IP

UDP

GTP-U

Physical Layer

ATM

Physical Layer

26 Internal Use


Iu Interface Signaling Plane Fails Description:

Iu Interface Signaling Plane Fails Troubleshooting

Use the DSP SAALLNK command to check the state of the SAAL link. The result shows the SAAL link is available. However, the alarm information shows the SAAL link is intermittent.

Use the DSP MTP3BLNK command to check the state of the MTP-3b link. The result shows the MTP-3b is unavailable.

Start an MTP-3b message tracing task. The tracing result shows that the MTP-3b link is faulty. That is, the RNC sends an SLTM message but does not receive the corresponding SLTA message.

Check the configuration of the MTP-3b link. The result shows that the signaling link code (SLC) configured on the RNC is 0 but that configured on the SGSN is 5.

Modify the SLC at SGSN to 0. The test result shows the MTP-3b link becomes normal.

27 Internal Use


Iu Interface Signaling Link Intermittent (to be continued) Description:

Iu Interface Signaling Link Intermittent Troubleshooting

Start an SAAL link tracing task to trace all messages except SD, POLL, and STAT.

It is found that the RNC sends the USTAT message frequently, which shows that some packets from CN to RNC are lost and the RNC requests the CN to resend the packet. If the packets are frequently lost, the SAAL link will disconnect. However, it will immediately recover after emergency proving.

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Iu Interface Signaling Link Intermittent (continued)

Packet loss on SAAL link is mainly due to dirty optical connector, poor connection of optical connector, clock problem, and traffic flow inconsistency at both ends

Because the packet loss occurs only in one direction, first check the traffic flow settings of RNC and CN. The check result shows that both service types are RTVBR, peak/sustainable rates are the same, and only the cell delay variation tolerance (CDVT) values are inconsistent. The CDVT of CN is 300000 and that of RNC is 10240 (unit: 0.1 µs); that is, the CDVT of RNC is only 1 ms. It is regarded that ATM cell delay variation results in packet loss.

Modify the CDVT of RNC to 102400 (10ms). This packet loss disappears.

29 Internal Use


CS-Related Services Unavailable Description:

The services related to CS are unavailable after a WOSE in WRBS is replaced by a WBIE

Troubleshooting When you add an AAL2 path/SAAL link/IPoA PVC outgoing fro

m an optical port on WLPU in WRSS and terminating at a WRBS, the BAM will assign a pair of VPIs and VCIs for connecting the PVCs configured at the WMUX and WLPU. If the VPIs and VCIs configured at the two boards are inconsistent, the AAL2 path/SAAL link/IPoA PVC will fail.

Therefore, if the WRBS is reset while the WRSS is not after reconfiguration in offline mode, the WMUX will use the new VPI and VCI while the WLPU will use the old ones. The inconsistency of the two PVCs will inevitably results in link malfunction

Reset the WRSS and WRBS after modification and the problem is then resolved

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31 Internal Use


5.1 Cell Troubleshooting 5.1 Cell Troubleshooting

5.2 Access Troubleshooting5.2 Access Troubleshooting

5.3 CS Traffic Troubleshooting5.3 CS Traffic Troubleshooting

5.4 PS Traffic Troubleshooting5.4 PS Traffic Troubleshooting

32 Internal Use

Cell TroubleshootingCell Troubleshooting

Cell setup signaling procedure Cell setup signaling procedure

NBAP_AUDIT_REQ

NBAP_CELL_SETUP_REQ

NBAP_CELL_SETUP_RSP

NBAP_COMM_TRANSP_CH_SETUP_REQ

NBAP_COMM_TRANSP_CH_SETUP_RSP

NBAP_SYS_INFO_UPDATE_REQ

NBAP_SYS_INFO_UPDATE_RSP

NBAP_AUDIT_RSP

NodeB RNC

33 Internal Use


Cell Setup Is Not Initiated After the Audit Process Ends Description

Cell setup is not started after the audit process ends Troubleshooting

Execute the LST CELL command. The result shows that the cell data is available, that is, cell setup is allowed. In addition, the corresponding LocalCell ID can be obtained.

The NBAP_AUDIT_RSP message includes the corresponding LocalCell information. The max TX power supported by LocalCell is 370 (37 dBm).

34 Internal Use


Execute the LST CELL command. The result shows that th

e max TX power configured for the cell is 430 (43 dBm), w

hich is greater than that supported by LocalCell. That is, th

e two power settings are not matched.

Through the communication with the maintenance enginee

rs of the NodeB, it can be concluded that the max TX powe

r 370 reported by the NodeB is correct. Then reduce the m

ax transmit power of the cell by MOD CELL and modify the

power threshold of PCPICH by MOD PCPICHPWR.

35 Internal Use


PRACH Setup Fails Discription

Pull out the WFMR and insert the WFMR again in another slot

Deactivate and activate the cell

Then, it is found that cell setup fails. It can be seen from the Iub interface that the common channel setup is not performed after the cell setup ends; instead, the cell deletion is directly started Possible cause

Troubleshooting

On the RNC, subsystem 0 of WSPUb can only correspond to the DSPs on the WFMR/WFMRb boards in odd slots; subsystem 1 of WSPUb can only correspond to the DSPs on the WFMR/WFMRb boards in even slots. However, the operator pulls the WFMR out of slot 3 but inserts it into slot 4. Thus, no DSPs are available during common channel setup and then there is no choice but to delete the cell

36 Internal Use


SCCPCH Setup Fails Discription

PRACH setup succeeds but SCCPCH setup fails during cell setup. It can be seen from the Iub interface that the SSCPCH deletion is started immediately after the setup ends

Possible cause

Observe the signaling messages of the transport layer over the Iub interface. The result shows that the QAAL2 connection setup is successful and the states of L2 resources are normal. Thus, it can be deduced that FP synchronization fails

Check the settings of AAL2 PATH and the corresponding PVC at the RNC and NodeB. It is found that there are such errors as PATH1 corresponding to PATH2

Modify the settings of the transport layer and then the problem is solved

37 Internal Use


Cell Frequency Fails to Be Modified Description

The UL frequency of the cell is modified from 1937.4 MHz to 1922.8MHz and DL frequency from 2127.4 MHz to 2112.8 MHz by MOD CELLSETUP. However, the UE cannot access the modified frequency

Troubleshooting None of the parameters in the MOD CELLSETUP command support

dynamic configuration. Only after the cell is set up again can they go into effect

The correct procedure for modifying the frequencies is as follows:

– Deactivate the cell by DEA CELL

– Modify the frequencies of the cell by MOD CELLSETUP

– Activate the cell by ACT CELL

– Thus, the new frequencies can become effective and the UE can access the cell on the new frequency

38 Internal Use


5.1 Cell Troubleshooting5.1 Cell Troubleshooting




39 Internal Use

Access TroubleshootingAccess Troubleshooting

Location Update Procedure

After powered on, the UE searches for a suitable cell as

follows:

Slot synchronization

Frame synchronization

Scrambling code group synchronization

Scrambling code synchronization

After finding a suitable cell, the UE exchanges information

with the CN through location update and notifies the CN of

the location area where it camps. Then the CN assigns a

temporary mobile subscriber identifier (TMSI) to the UE

40 Internal Use


Attach Procedure

The attach procedure is the same as the location update

procedure in the access stratum (AS). Seen from the AS, the

procedure is as follows:

The UE and CN set up a signaling connection

The UE sends an ATTACH REQUEST message to the CN

The CN sends an ATTACH ACCEPT message to the UE

The UE sends an ATTACH COMPLETE message to the CN

The UE and CN release the signaling connection

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The Procedure of Combined Location Update

The procedure of combined location update is the same as that of locati

on update. Seen from the AS, the procedure is as follows:

UE and SGSN set up a signaling connection.

UE sends the ATTACH REQUEST message to SGSN, with the atta

ch type of combined attach.

SGSN sends the LOCATION UPDATE REQUEST message to MS

C for IMSI combined attach.

MSC sends the LOCATION UPDATE ACCEPT message to SGSN.

At the same time, SGSN completes the attach procedure.

SGSN sends the ATTACH ACCEPT message to UE.

UE sends the ATTACH COMPLETE message to SGSN.

UE and SGSN release the signalling connection

42 Internal Use


UE Fails to Access Cell When Inner Loop Power Control Is Disabled Description

During a cell capacity test indoors, it is found that the UE cannot access the cell when the total number of the connected UEs is 52 (not up to the upper limit yet). Here, “” is displayed on the UE; or, even if there is a cell indicator occasionally, it disappears quickly. The DL TX power is up to the limit.

During a cell capacity test outdoors, only 44 UEs can access the cell and then two of them are disconnected. In the case of 40 UEs, use a test UE accessing the cell. It is found that the Transmission Power Control (TPC) value sent by the uplink is a negative value, which shows that the TX power of the NodeB should be reduced. However, the TX power remains unchanged.

43 Internal Use


Troubleshooting

As the inner loop power control is disabled, the TX power

adopts the initial value. This value is too great and thus

results in serious interference.

Enable the inner loop power control, set

CORRMALGOSWITCH:

PCSWITCH=DOWNLINK_POWER_BALANCE_SWITCH-1;

44 Internal Use


UEs of Some Type Cannot Access Cell

Description

UEs of some type cannot access cell while UEs of other types can

Troubleshooting

This NodeB is configured with two cells with IDs of 41364 and 413

63. The ID of the cell to be accessed is 41364. However, in the R

NC only the cell 41363 is configured with its intra-frequency neigh

boring cell 41364 but the cell 41364 fails to be configured with its i

ntra-frequency neighboring cell 41363.

This type of UEs require the cell to be accessed must have an intr

a-frequency neighboring cell; otherwise, cell access will fail.

Add the intra-frequency neighboring cell in online mode.

45 Internal Use


UEs of Some Type Fail to Attach System or Perform Location Update Description

During a single-cell coverage test, it is found there are three UEs failing to be attached while the test equipment shows the received signals are of enough strength. The specific situation is that the UE is normal every time it is powered on but, about 10 seconds later, it cannot be attached

Troubleshooting Some types of UEs only support RRC connection over dedicated ch

annel. If over common channel, the UE will not access the cell. Disable the function of setting up RRC connection over common ch

annel

46 Internal Use






47 Internal Use

CS Traffic TroubleshootingCS Traffic Troubleshooting

Uplink voice noise is usually caused by high BLER of Uu in

terface. First check the Uu interface

It is normal that the voice is intermittent when the UE is on

the edge of the coverage area or when the UE is going int

o or out of shadow areas

For downlink voice noise, intermittent voice is due to the i

nsufficiency of the AAL2 path bandwidth of the Iub UP

48 Internal Use

CS Traffic TroubleshootingCS Traffic Troubleshooting

Audio Quality Not Good Description

During conversation, there is big noise. The audio quality is very low.

Troubleshooting

Observe UL and DL BLERs on both UE and NodeB. There is no high BLER

Check the AMR bit rate format configured in RAB assignment message by Iu interface tracing. It is found that only the bit rate of 12.2 kbit/s and zero bit rate are configured

The above problem is due to no silence indicator (SID) configured in RAB assignment message. Thus, noise will be coded and sent as audio data frames when there is no audio. This results in low audio quality

Add SID bit rate format at the CN side. The fault is cleared

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50 Internal Use

PS Traffic TroubleshootingPS Traffic Troubleshooting

Description The Block Error Rate (BLER) of Uu interface rises suddenly. The application server fails. The UE is on the edge of the coverage area or the UE is going i

nto or out of shadow areas The general consideration of Locating the Traffic faults:

Trace the interface signaling procedure. Compare to the right signaling procedure Analyze the signaling procedure and locating the faults

51 Internal Use

PS Traffic TroubleshootingPS Traffic Troubleshooting

FTP Service Rate is Low

Description

The PS domain FTP service can be set up normally at some test po

int. However, the FTP download rate is very low

Troubleshooting

Observe UL and DL BLERs on RNC (or NodeB) or UE. The res

ult shows that both BLERs are a bit high, which indicates that th

e RL quality is poor

Error blocks on air interface increases data retransmissions by

RLC and lowers service rate

Analyze radio parameter settings or check the state of the Node

B. The result shows that this test point is located on the edge of

the isolated cell. The cell coverage is not good enough

Improve the coverage of this test point. Then the fault is cleared

11 bsc6800 troubleshooting issue3.0

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