Ericsson RAN GSM Training

Troubleshooting Common

Ericsson GSM Alarms

A step by step guide.

Common Ericsson GSM Alarms

MO FLT= OML FAULT

DIGITAL PATH FAULT SUPERVISION

CELL LOGICAL CHANNEL AVAILABILITY SUPERVISION

MO FLT= PERMANENT FAULT

MO FLT= BTS INTERNAL


Cont. EXTERNAL ALARMS; see Additional Info

PWR COMMERCIAL;RECT 24V MAINS;BATTERY

CORRELATED LIKE: MO FLT= TS SYNC FAULT

CELL LOGICAL CHANNELS SEIZURE SUPERVISION

CP AP COMMUNICATION FAULT


Cont.

MO FLT= LOOP TEST FAILED

LOCAL MODE & OPERATOR CONDITION

MO FLT= OML FAULT

A fault exists in the communications link between the BSC and the BTS.

Alarm can come in as either Major or Critical.

Can come in on the CF, TRX, or both.

90% of the time is due to a down or faulty T1.

Can also result from a faulty TRX or loss of communication from the BSC to the TRX.

NOTE:

Prior to troubleshooting this or any other Ericsson alarm, always perform a right

click on the alarm in Netcool and chose the View alarms at this Location

option to view all alarms at this site to see if this could be a secondary affect

caused by power, maintenance, ECT and always search CTS to see if there is an

existing Ticket on the site for this or any related issue.

Recommended Troubleshooting

Steps

1. Log into appropriate Complex/BSC and

retrieve an alarm list for the parent RXOTG

by running the RXASP:MO=RXOTG-__;

for the CF listed.

SKCAB07 SCRMCAT021 MO=RXOCF-55 SLOGAN=OML FAULT

The TG number will be the same as the CF listed in the alarm.

Connecting to SKCAB07... (Use 'quit' to logoff)

3. Create a CTS Ticket

Connecting to SKCAB07... (Use 'quit' to l ogoff)

the site. If this is the case, the primary DIP may show WO when a portion

of the site is down (when in reality it is the second DIP that has faulted out).

You may need to determine what the secondary DIP is (if it exists) and

status it. It is important to get the correct DIP information to the field / telco

group so the correct circuit will be tested.

4. Status the DIP Quality

the circuit tests clean and the OML faults are still present then forward the ticket

to the field to have them check the TRXs. If the circuit test clean and the OML

faults clear, wait about 20 minutes and status the site again. If the OML faults

clear then the site has restored and you can close the TT. If the faults return then

send the ticket to the field tech with your troubleshooting notes to have him

investigate the issue.

It is important to note at this point that the CF/TG number are not always the

same as the DIP number. Secondary T1s will have a number different than that

of the TG. There can be 2 or more DIPs assigned to a CF/TG. In these cases

you will need to run a few extra commands to find the correct DIP number to

status and include in your ticket. Consider the following example using the same

commands used on the previous example.

Status the DIP using the DTSTP

command

Status DIP Quality DTQUP

RXAPP Command

5496/24=229 so 229RB# will be your third DIP. Now we can status all three DIPs

to see which one is faulty.

RXAPP Command Cont.

RBLT3-2167 8 UNDEF IDLE YESRBLT3-2168 9 UNDEF IDLE YES

RBLT3-2169 10 UNDEF IDLE YESRBLT3-2170 11 UNDEF IDLE YESRBLT3-2171 12 UNDEF IDLE YESRBLT3-2172 13 UNDEF IDLE YESRBLT3-2173 14 UNDEF IDLE YESRBLT3-2174 15 UNDEF IDLE YES



RBLT3-5501 292 UNDEF IDLE YESRBLT3-5502 293 UNCONC SPEECH/DATA YESRBLT3-5503 294 UNDEF IDLE YESRBLT3-5504 295 UNDEF IDLE YESRBLT3-5505 296 UNDEF IDLE YESRBLT3-5506 297 UNDEF IDLE YES


RBLT3-5513 304 UNDEF IDLE YESRBLT3-5514 305 UNDEF IDLE YESRBLT3-5515 306 UNDEF IDLE YESRBLT3-5516 307 UNDEF IDLE YESRBLT3-5517 308 CONC TRXC SIGNAL NO 2 3 4 5RBLT3-5518 309 CONC TRXC SIGNAL NO 0 1

RBLT3-5519 310 CONC CF/TRXC SIGNAL NO 62 6 8 9 10

Look at the result printout and find the range of RBLT or RBLT3 devices listed.

Usually it is easy to tell if there is more than one DIP assigned because the RBLT

range will have a noticeable skip in the numbering. In this case, the devices start

with RBLT3-1560 through 1583 (first DIP). Then jumps to RBLT3-2160 through

2183 (second DIP). Then Jumps again to RBLT3-5496 through 5513 (third DIP).

To find the DIP number form these devise ranges simply divide any number in

the device range by 24 and that will give you your DIP number. 1560/24=65 so

60RB3 is your first DIP. Then

2160/24=90, so 90RB3 is your second DIP.

5496/24=229 so 229RB3 will be your third DIP. Now we can status all three DIPs

to see which one is faulty

Status DIP 65RB3

Status DIP 229RB3

DIGITAL PATH FAULT SUPERVISION

Indicates A T1 is down or is above the

error threshold.

Can be either a T1 to a cell site or a

Switch DIP.

Usually accompanied be an OML Fault Alarm.

Comprised of 24 devices, 1 for each DSO.

DIGITAL PATH FAULT SUPERVISION DIP=81RB3; FUALT=AIS


Steps

1. Log into the appropriate Complex/BSC

and status the DIP using the

DTSTP:DIP=____; (81RB3 in this case)

Command to check and see if the DIP is

down or taking errors.

Status DIP

Connecting to RVCAB08... (Use 'quit' to logoff)

2.Find the SNTwith DTDIP

Command

109RA3 RALT3-2616&&-2639 4378RB3 RBLT3-1872&&-1895 5179RB3 RBLT3-1896&&-1919 5280RB3 RBLT3-1920&&-1943 5381RB3 RBLT3-1944&&-1967 5482RB3 RBLT3-1968&&-1991 5583RB3 RBLT3-1992&&-2015 5684RB3 RBLT3-2016&&-2039 5785RB3 RBLT3-2040&&-2063 5886RB3 RBLT3-2064&&-2087 5987RB3 RBLT3-2088&&-2111 6088RB3 RBLT3-2112&&-2135 6189RB3 RBLT3-2136&&-2159 6290RB3 RBLT3-2160&&-2183 6391RB3 RBLT3-2184&&-2207 6492RB3 RBLT3-2208&&-2231 6593RB3 RBLT3-2232&&-2255 6694RB3 RBLT3-2256&&-2279 6795RB3 RBLT3-2280&&-2303 6896RB3 RBLT3-2304&&-2327 6997RB3 RBLT3-2328&&-2351 7098RB3 RBLT3-2352&&-2375 7199RB3 RBLT3-2376&&-2399 726RTG3 RTGLT3-144&&-167 817RTG3 RTGLT3-168&&-191 828RTG3 RTGLT3-192&&-215 83

SNT EQLEV PROT SDIP SUBSNT DEFPST SNTP MODEETM3-2 1 2ETM3 0 XM-0-0-6 2176

1 XM-0-0-17 0END

3. Status the SNT for the DIP's and their Device ranges

NTCOP:SNT=EMT3-2; Cont.

Now that we have found our DIP and its device range (located to the right of the

DIP number in the printout) we can status this device range. The devise range

numbers are the numeric value configured in the switch and the site for all 24

devises connected to that DIP.

Note: Some data (DIPS) were removed from this printout for spacing reasons.

4.Status the DIPs Device Range STDEP:DEV=RBLT3-1944&&-1967

5. Find the Site and TG.

RXMDP:MOTY=RXOTS,DEV=RBLT3-1952;

6. Status the TG to get the site ID

7. Verifying the TG has a down T1.

RXMSP:MO=RXOTG-79,SUBORD;

would create a CTS ticket to send to Telco with the DTSTP, RXASP, and the

RXMSP along with the correct ED path for the circuit to be tested.

Looking at this we see that not all the timeslots are in order or on the same

radio. This is done to split the rescores from the different T1s to each sector for

redundancy purposes.

7. RXMSP:MO=RXOTG-79,SUBORD; Cont.RXOTS-79-6-6 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-6-7 OPER 0000 0000 0840 DIS UNCONFRXOTX-79-6 OPER 0000 0000 0000 ENA ENARXOTRX-79-7 OPER 0000 0000 STARXORX-79-7 OPER 0000 0000 0000 ENA ENARXOTS-79-7-0 OPER 0000 0000 0000 ENA ENARXOTS-79-7-1 OPER 0000 0000 0000 ENA ENARXOTS-79-7-2 OPER 0000 0000 0000 ENA ENARXOTS-79-7-3 OPER 0000 0000 0000 ENA ENARXOTS-79-7-4 OPER 0000 0000 0000 ENA ENARXOTS-79-7-5 OPER 0000 0000 0000 ENA ENARXOTS-79-7-6 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-7-7 OPER 0000 0000 0840 DIS UNCONFRXOTX-79-7 OPER 0000 0000 0000 ENA ENARXOTS-79-9-0 OPER 0000 0000 0000 ENA ENARXOTS-79-9-1 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-9-2 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-9-3 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-9-4 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-9-5 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-9-6 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-9-7 OPER 0000 0000 0840 DIS UNCONFRXOTX-79-9 OPER 0000 0000 0000 ENA ENARXOTRX-79-10 OPER 0000 0000 STARXORX-79-10 OPER 0000 0000 0000 ENA ENARXOTS-79-10-0 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-1 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-2 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-3 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-4 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-5 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-6 OPER 0000 0000 0840 DIS UNCONFRXOTS-79-10-7 OPER 0000 0000 0840 DIS UNCONFRXOTX-79-10 OPER 0000 0000 0000 ENA ENAEND

MO FLT= BTS INTERNAL

A fault has occurred in the CF or in one or

more of the MOs

Can occur in the CF, TRX, RXOTX, RXORX

Usually presents in Netcool as a Major

Can sometimes be restored remotely

MO FLT= BTS INTERNAL 2 alarms: RXOTX-195-0 RXOTX-195-1


Steps1. Retrieve alarm printout from parent RXOTG

RADIO X-CEIVER ADMINISTRATION

MANAGED OBJECT ALARM SITUATIONS

MO RSITE ALARM SITUATION

RXOTG-195 LA0166

RXOCF-195 LA0166 BTS INT UNAFFECTED

RXOTX-195-0 LA0166 BTS INT AFFECTED

RXOTX-195-1 LA0166 BTS INT AFFECTED

END

Determine if the fault is service-affecting or if any other MOs are in alarm by

looking at the alarm list for the parent RXOTG. If it shows BTS INT

UNAFFECTED, this will generally not be service-affecting and will not warrant a

critical ticket on the RXOCF itself

If any other MOs show AFFECTED alarm situations, then troubleshoot them

appropriately. The fault codes reflected by the RXOCF will aid in determining the

problems on any subordinate MOs.

When the RXOTX or RXORX show BTS INT AFFECTED, it is out of service

(blocked). Usually the RXOCF or the parent RXOTRX will show a BTS INT

UNAFFECTED but will not be blocked. However, because the TX and RX are

blocked, from an operational standpoint the TRX is out of service as well since it

has no operating transmit or receive function.

Look the fault code up in the maintenance manual fault list to determine what it

means. The manual may also direct you to pull the fault codes from the parent

MOs that are showing unaffected faults to help further isolate the problem.

2) Retrieve the fault code(s) for the RXOCF

2. Retrieve the fault code(s) RXMFP:MO=RXOTG-195,SUBORD,FAULTY;

2. Retrieve the fault code(s) Cont.

40

MO BTSSWVER

RXOTX-195-0 ER A-G04-R08-V01

RU RUREVISION RUSERIALNO

0

RUPOSIT ION RULOGICALID

STATE BLSTATE INTERCNT CONCNT CONERRCNT LASTFLT LFREASON

NOOP BLO 00000

FAULT CODES CLASS 1B4

MO BTSSWVER RXOTX-195-1 ER A-G04-R08-V01

RU RUREVISION RUSERIALNO0

RUPOSIT ION RULOGICALID

STATE BLSTATE INTERCNT CONCNT CONERRCNT LASTFLT LFREASONNOOP BLO 00000

FAULT CODES CLASS 1B

4END

2) Retrieve the fault code(s) for the MO

Note: The actual faults are listed at the end of the printout. From here we can

see that the fault in on RXOTX-195-0 and 195-1. The fault code is 1B4. We can

now reference our documentation to see what the fault is and what actions are

required.

3. Reference the Fault code Fault No. AO TX I1B: 4

Fault name: TX antenna VSWR limits exceeded

Related fault:

SO CF I2A:8 VSWR limits exceeded

SO CF RU:40 Antenna

Description: When VSWR at CDU output exceeds the class 2 limit defined in IDB with OMT (default value: 1.8), the fault SO CF I2A:8 arises with RU map "Antenna". When VSWR exceeds the class 1 limit (default value: 2.2), the fault AO TX I1B:4 arises on TX.

Possible reasons:

Faulty IDB

Faulty CDU

TX antenna/feeder faulty or disconnected

Pfwd/ Prefl cables faulty

Measurement receiver in TRU/CU (in some cases) faulty.

Action

Reference the fault code given from our documentation to view the fault and see

what are the next steps to take. From our documentation we can see that this is

a VSWR alarm

Fault Internal 1A 4 TX Antenna VSWR Limits Exceeded

This fault means that the VSWR (voltage standing wave ratio) on the transmit

antenna or antenna feeder is too high. To keep the reflected power from burning

up the transmitter or power amplifiers, the transmitter is shut down. The RXOCF

will usually also show unaffected fault internal 2A 8 as well.

This fault is NOT remote-repairable. Even if it is a bogus alarm, generally any

blocking/deblocking of TX, TRX, CF, etc will only remove the alarm for a short

period of time, and it will return on the next periodic VSWR measurement.

Cut a ticket to the field with RXASP and RXMFP printout and explanation that TX

has high VSWR. The radio is out of service.

CELL LOGICAL CHANNEL

AVAILABILITY SUPERVISION

Generated to inform you that a number of

available channels have fallen below defined

limits.

Usually accompanied or correlated with additional alarms for the MOs that have

caused the channel failures.

Can present as a Critical or Major in Netcool.

Can also be caused by a down T1.

CELL LOGICAL CHANNEL AVAILABILITY SUPERVISION CELL=SD0379Y; CHTY PE=TCH


Steps

1. Right click on the alarm in Netcool and

chose the View Alarms At This Locationoption to see if there are secondary or

correlated faults that may be causing the

Alarm.

1A. If there are no secondary or correlated

alarms, search CTS on the site for

previously opened tickets.

Usually these are accompanied by secondary and/or correlated alarms. These

can come in as Major or Critical alarms. If you do find a secondary alarm, no

matter the severity, troubleshoot that alarm as instructed before moving on to the

next step. If there are no other issues at the site then we will proceed to find the

correct TG for the site in the alarm.

2. Find the correct TG correlated

with the alarm.

Connecting to SDCAB09... (Use 'quit' to logoff)

3. Status the Alarm Situation on the

TG.

4. Run RXMFP command to get

the fault codes.

4. Run RXMFP command to get

the fault codes. Cont.MO BTSSWVER RXOTX-91-4 ERA-G04-R08-V01


RUPOSITION RULOGICALID



MO BTSSWVER RXOTX-91-5 ERA-G04-R08-V01


RUPOSITION RULOGICALID



END

Ericsson RAN GSM Training

Documents

Transcript of Ericsson RAN GSM Training