09_RA4112AEN05GLA0_Flexi Multiradio Basic Troubleshooting

1 Nokia Siemens Networks RA4112AEN05GLA0

Flexi Multiradio LTE BTS Basic Troubleshooting


Objectives

After completing this learning element, the participant should be able to:

Explain basic alarms and alarm handling with Flexi Multiradio LTE BTS

Apply basic troubleshooting


Content

Retrieve information on alarms and troubleshooting (NOLS and BTS Site Manager)

Localize alarm

Typical alarms in basic troubleshooting seen from BTS Site Manager perspective

Basic troubleshooting steps


Troubleshooting Information in NOLS

Click on Reference in the list of Operating Documents and than on Alarms


Information sources in fault situations

Use at least the following information sources when carrying out troubleshooting:

Faults

Faults are the primary source of information in most situations where troubleshooting is needed. Faults are printed out on the fault printer and/or other devices that you have specified for the network element.

For instructions, see Checking BTS faults (NOLS). For fault descriptions, see Flexi Multiradio BTS Faults document (NOLS).

BTS documentation

You can find the latest information in the updated BTS documentation and Technical Notes. Access to the web pages is confined and information is delivered via your local Nokia Siemens Networks representative. Multiradio BTS LTE documentation is delivered via PIC (Product Information Center). The latest SW related documentation, such as List of Generic Faults and Release Note, can be found on the Multiradio BTS Technical Support web pages.

BTS log files

Snapshot files are useful for troubleshooting purposes and must be attached when Resolve case is raised to Tier 3 level. Logs can be fetched locally or remotely with BTS Site Manager. For instructions, see BTS Site Manager Online Help(NOLS).


Alarm Severity


Retrieving alarm information in BTS Site Manager

1

2

3


Identifying the alarm source

1

2

3

1.Select Alarm in Faults window

2.Click on icon Show source 3.Alarm source is identified (see also

Source column in the Fault view)


LOS Alarm

LOS alarm is the root cause.

X2AP and S1AP alarms are just the consequences in this case as

physical interface is disconnected on which all applications (X2AP,

S1AP,..) should run.

Prerequisite for S1AP and X2AP setup is SCTP association which is in

this case also not established.

Therefore Transport layer connection failure is raised.

eNB is in BTS configured state as S1AP link is down (no connection to MME)


MME IP address

Check MME configuration and IP address in the

Commissioning Wizard


Adjacent eNB configuration in RL20

In order to check adjacent eNBs configuration in RL20 check

ADIPNO Managed Object under LNBTS.


Adjacent eNB configuration in RL30

In order to check adjacent eNBs configuration in RL30 check

LNADJ Managed Object(s) under LNBTS.

LNADJ Managed Object(s) are normally created based on

ANR feature implementation and PCI-IP mapping table.


S1 Interface failure

If S1 interface failure is raised than SCTP association is

established between eNB and MME (eNB and MME exchange

SCTP heartbeats) but S1 setup request was not successful and

S1AP is down.


Transport layer connection failure in X2 interface

Source: SCTP link for X2 interface.

The transport path (SCTP) for connection to an adjacent BTS has

broken. The reason for this can be an unplugged cable to the adjacent

BTS. No transport path available to pursue operation on the faulty

connection with the adjacent BTS.


PCI-IP address mapping table

PCI-IP address mapping table

In case wrong table might be provisioned from

OSS, X2 can be established to the wrong

neighbor.


Failure in optical RP3 interface

Dirty or broken optical cable(s) and/or SFPs or

wrong SFP inserted either in FSM or FRM are main

causes for RP3 alarm.


Unit blocked - FRM

Block/Unblock will reset the unit.


Module in Configuring State

Unblocked unit in configuring state.

Alarm Unit blocked is still active.


Block/Unblock BTS

Block/Unblock BTS will reset the BTS.

TRS shall NOT be reset.


Reset Site

Reset Site will reset both BTS and TRS.


eNB connection to iOMS: M-Plane (OAM) link

Two iOMSs can be configured in eNB (Primary and Secondary).

No alarm is raised in BTS Site Manager in case eNB is

disconnected from iOMS.

However, the link from NetAct to eNB (through iOMS) is broken.


Failure in connection between BTS and iOMS or 3rd party tool

Check connectivity to the 3rd party tool if used for e.g.

for subscriber trace.


GTP-U Path Failure alarm

GTP-U path supervision is optional feature.

Network element did not respond to the GTP-U: Echo

Request message within time.


GTP-U Path Failure alarm continued

Check GTP-U path configuration and IP address of the SGW in the

Commissioning Wizard.

If GTP-U supervision is set to the value different than zero supervision

is switched on.

SGW IP address set GTPU object is not affecting user plane traffic.


VSWR alarm

Alarms:

Radio resources switched off and TX failure in MIMO are consequences of the VSWR alarm.

voltage standing wave ratio ; VSWR

Ratio of maximum to minimum voltage in the

standing wave pattern that appears along a

transmission line. It is used as a measure of

impedance mismatch between the transmission line

and its load.


Block Cell


Block Cell - continued

Administrative state of the cell and

Blocking state are not the same.

eNB is only Integrated as none of the configured cells is operational.

Signaling link to MME is active.


Change Cell Administrative State

Cell administrative state can be either:

unlocked shutting down locked


Cell Administrative State shutting down

Cell final state is -

Locked


IP Connectivity Test

IP Connectivity Test

Scope


Save BTS snapshot

BTS Snapshot files are useful for troubleshooting purposes.