Huawei HG8245T Router Manual PDF (Setup & Configuration Guide)

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Possible Cause

Judgment Criterion

Troubleshooting Method

The PON port is faulty.

If either of the following two

situations occurs, the PON pot

is faulty.

l

Run the

display port state

command to query the

status of the PON port. It is

found that abnormal items

exist in the query result. For

example, the laser status

(

Laser state

) is abnormal

and the transmit optical

power (

TX power

) exceeds

the normal range (1.5-5.0

dBm).

l

Migrate the service to

another port. It is found that

the ONU goes online

normally.

Replace the optical module of

the PON port or replace the

board.

The board or the slot is

faulty.

All the ONUs connected to the

board fail to go online.

Change the board to another

slot. If the fault persist, replace

the board.

Step 3

Check for the possible causes on the ODN and troubleshoot the faults accordingly. If the ONU

still fails to go online after that, proceed to

Step 4

.

Possible Cause

Judgment Criterion

Troubleshooting Method

The optical fiber

connector is not clean.

NOTE

An unclean optical fiber

connector will cause

excessive attenuation and

abnormal reflection.

1.

Test the backbone fiber and

branch fiber by using the

OTDR. It is found that the

reflection and return loss

are abnormal.

2.

Check the optical fiber

connector on site by using

the optical fiber endface

detector. It is found that the

optical fiber connector is

not clean.

Clean the optical fiber

connector. For details about

how to clean the connector, see

Cleaning the Connector of an

Optical Fiber.

The optical fiber is bent

excessively.

NOTE

Optical signals attenuate

seriously on an optical

fiber with an excessively

small bending radius.

1.

Test the backbone fiber and

branch fiber by using the

OTDR. It is found that

abnormal return loss points

exist on the optical fiber.

2.

Check the optical fiber on

site. It is found that the

optical fiber is bent

excessively.

Route and bundle the optical

fiber in a proper manner.

EchoLife HG8010/HG8240B/HG8245T/HG8247T GPON

Terminal

Service Manual

5 Maintenance and Troubleshooting

Issue 01 (2011-10-18)

Huawei Proprietary and Confidential

353

Page 362 / 429

Possible Cause

Judgment Criterion

Troubleshooting Method

The optical fiber is not

firmly connected or

different types of optical

fiber connectors are

interconnected.

NOTE

If the optical fiber is not

firmly connected or

different types of optical

fiber connectors are

interconnected, the

attenuation and reflection

will be excessively large.

1.

Test the backbone fiber and

branch fiber by using the

OTDR. It is found that

abnormal return loss points

exist on the optical fiber.

2.

Check the optical fiber

connectors on site. It is

found that the optical fiber

is not firmly connected or

PC connector (blue) and

APC connector (green) are

interconnected.

l

If the optical fiber is not

firmly connected, reconnect

the optical fiber firmly.

l

If different types of optical

fiber connectors are

interconnected, replace the

incompatible connector

with a compatible one or

replace relevant devices,

such as the optical splitter.

NOTE

In the scenario of the CATV

service, it is recommended that

you use APC connectors (green)

only.

The multi-mode optical

fiber is used as the

backbone or branch

optical fiber.

NOTE

If the multi-mode optical

fiber is used as the

backbone or branch optical

fiber, the optical signal

attenuates quickly and the

return loss increases.

1.

Check the backbone fiber

and branch fiber by using

the OTDR. It is found that

optical signals attenuate

seriously.

2.

Check the optical path on

site. It is found that the

multi-mode optical fiber is

used. The multi-mode

optical fiber can be

recognized by its physical

features such as its color.

Replace the multi-mode optical

fiber with the single-mode

optical fiber.

The optical attenuation

of the optical path is

excessively small.

NOTE

l

If the optical

attenuation of the

optical path is

excessively small, the

optical power received

by the ONU will

exceed the overload

optical power of the

ONU.

l

Such a situation occurs

usually in labs, where

the OLT and ONU

may be directly

connected to each

other through a short

optical fiber.

If either of the following two

situations occurs, the optical

attenuation of the optical path

is excessively small.

l

Measure the receive optical

power of the ONU by using

the optical power meter. It

is found that the actual

receive optical power of the

ONU is greater than -8

dBm.

l

Check the optical path

between the OLT and ONU.

It is found that the optical

attenuation of the optical

path is excessively small.

The normal attenuation

range is 10-25 dB.

Add an optical attenuator on the

optical path between the OLT

and ONU.

EchoLife HG8010/HG8240B/HG8245T/HG8247T GPON

Terminal

Service Manual

5 Maintenance and Troubleshooting

Issue 01 (2011-10-18)

Huawei Proprietary and Confidential

354

Page 363 / 429

Possible Cause

Judgment Criterion

Troubleshooting Method

The ODN is not properly

planned.

NOTE

l

The split ratio of the

ODN link is not

determined by the

number of ONTs

connected but by the

split ratio of optical

splitters. When an

optical splitter is

connected to the ODN,

attenuation occurs and

the split ratio of the

optical splitter needs to

be calculated.

l

Protocols specify that

the receive optical

power of the OLT

should not exceed 15

dB. In addition, the

difference between the

maximum optical

power and the

minimum optical

power should not

exceed 15 dB.

The ODN does not meet the

requirements of the ODN link

plan or GPON Class B+.

l

Three-level splitting exists

in the ODN.

l

The network coverage of

the ODN exceeds 20 km by

far.

l

The split ratio exceeds the

maximum split ratio that the

board allows. Assuming

that the maximum split ratio

of a board is 1:64. If the

first-level split ratio is 1:8

and the second-level split

ratio is 1:16, the actual split

ratio is 1:128, which

exceeds the maximum split

ratio of the board.

l

The optical attenuation

difference of two optical

paths exceeds 15 dB.

Optimize the ODN to meet

Huawei's ODN planning

requirements and protocol

requirements.

The optical splitter is

faulty or the connectors

on the optical splitter are

not clean.

Measure the input and output

optical power of the optical

splitter by using the optical

power meter. It is found that the

actual attenuation exceeds the

theoretical attenuation.

NOTE

The faults in the optical splitter

cannot be located by the OTDR

because the OTDR cannot

penetrate the optical splitter.

Replace the faulty optical

splitter or clean the connectors

on the optical splitter.

A backbone fiber break

occurs.

1.

Check the backbone fiber

by using the OTDR. It is

found that a backbone fiber

break occurs.

2.

Check the optical fiber on

site. It is found that the

optical fiber is broken or not

connected.

Reconnect the branch optical

fiber.

EchoLife HG8010/HG8240B/HG8245T/HG8247T GPON

Terminal

Service Manual

5 Maintenance and Troubleshooting

Issue 01 (2011-10-18)

Huawei Proprietary and Confidential

355

Page 364 / 429

Possible Cause

Judgment Criterion

Troubleshooting Method

A branch fiber break

occurs.

1.

Check the branch fiber by

using the OTDR. It is found

that a branch fiber break

occurs.

2.

Check the optical fiber on

site. It is found that the

optical fiber is broken or not

connected.

Reconnect the branch optical

fiber.

Step 4

Check for the possible causes on the ONU and troubleshoot the faults accordingly. If the ONU

still fails to go online after that, proceed to

Step 5

.

Possible Cause

Judgment Criterion

Troubleshooting Method

The ONU is not powered

on.

If either of the following two

situations occurs, the ONU is

not powered on.

l

The 0x2e11a00b The

dying-gasp of GPON ONTi

(DGi) is generated alarm is

generated on the OLT, but

the corresponding recovery

alarm is not generated.

l

Check the power supply of

the ONU. It is found that the

power supply of the ONU

fails or is turned off.

Restore the power supply of the

ONU.

A rogue ONU (such as a

continuous-mode ONU)

exists on the network and

affects other ONUs.

NOTE

If a rogue ONU exists, the

ONU that fails to go online

may be a normal one and

the ONU that can go online

may be a rogue one.

If either of the following two

situations occurs, a rogue ONU

exists.

l

The 0x2e314021 There are

illegal incursionary rogue

ONTs under the port alarm

is generated on the OLT.

l

The 0x2e314022 The ONT

is rogue ONT alarm is

generated on the OLT.

l

Connect the optical fiber of

the OLT port to the optical

power meter for

measurement. It is found

that the optical power is

greater than -45 dB. This

indicates that a continuous-

mode ONU or irregular-

mode ONU exists.

Replace the rogue ONU with a

normal one.

EchoLife HG8010/HG8240B/HG8245T/HG8247T GPON

Terminal

Service Manual

5 Maintenance and Troubleshooting

Issue 01 (2011-10-18)

Huawei Proprietary and Confidential

356

Page 365 / 429

Possible Cause

Judgment Criterion

Troubleshooting Method

The information (SN) for

ONU authentication

conflicts; hence, the

power-on ONU fails to

go online.

The 0x2e305015 The

authentication information of

the ONTs conflicts alarm is

generated on the OLT.

Replace the ONU with

conflicted SN.

The ONU hardware is

faulty.

If either of the following two

situations occurs, the ONU

hardware is faulty.

l

The LEDs of the ONU are

off when the ONU is

powered on.

l

After the ONU is replaced

with another ONU, the new

ONU is auto discovered by

the OLT.

Replace the faulty ONU or the

optical module of the ONU.

The optical module of the

ONU is abnormal. For

example, the transmit

optical power of the

optical module is

excessively small or its

receiver sensitivity is

low.

Replace the faulty ONU with a

normal one. It is found that the

new ONU is auto discovered by

the OLT.

An alternative is to locate the

fault as follows:

l

Set the optical module of

the ONU to the continuous

mode, and measure the

transmit optical power by

using the optical power

meter. It is found that the

actual transmit optical

power is beyond the normal

range (1.5 dBm to 5.0

dBm).

l

Measure the receive optical

power of the ONU by using

the optical power meter. It

is found that the actual

receive optical power is

within the normal range

(-27 dBm to -8 dBm).

Replace the faulty ONU or the

optical module of the ONU.

The Patch cord of the

ONU is broken or bent

excessively.

Check the Patch cord of the

ONU. It is found that the Patch

cord is broken or bent

excessively.

Replace the Patch cord of the

ONU.

Step 5

Record the results of the preceding steps in the form for reporting a fault, fill in the form

completely, and then submit the form to Huawei for technical support.

EchoLife HG8010/HG8240B/HG8245T/HG8247T GPON

Terminal

Service Manual

5 Maintenance and Troubleshooting

Issue 01 (2011-10-18)

Huawei Proprietary and Confidential

357

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