Symptom:

One NE at a station is unreachable by the U2000, whereas the other NEs at this station are

reachable. The services on the NE are not interrupted.

Impact on System:

The NE is unreachable by the U2000.

Possible Causes

Cause 1: The network cable is disconnected or loose. For example, between the GNE and

the computer where the NMS server is installed, between the GNE and non-GNEs, between

the master and slave subrack of an NE.

Cause 2: The NE Attributes of the NE is changed by mistake, such as the IP address,

Gateway Type, User Name or Password

Cause 3: The system control board on the NE is faulty.

Cause 4: If the NE has an OSC board, the fiber jumpers between OSC and FIU board are

faulty or the OSC board is faulty on the unreachable NE or on its opposite NE.

Cause 5: The NE(non-first gateway NE) encounters system control board active/standby

switching.

Cause 6: Coherent and non-coherent boards are interconnected.

Tools, Equipment and Materials

U2000, Web LCT, cable tester.

Procedure:

Cause 1: The network cable is disconnected or loose. For example, between the GNE and

the computer where the NMS server is installed, between the GNE and non-GNEs, between

the master and slave subrack of an NE.

1. Check whether network cables are correctly connected between the GNE and the

computer where the NMS server is installed, between the GNE and non-GNEs,

between the master and slave subrack of an NE.

2. Use a cable tester to test the network cable and the network port. If the network cable

is faulty, replace it.

3. If the network cable is good, the interface board (such as EFI, EFI1, EFI2, or AUX)

is faulty, replace it.

Cause 2: The NE Attributes of the NE is changed by mistake, such as the IP address,

Gateway Type, User Name or Password.

1. Log in to the NE on the Web LCT and restore the initial IP address gateway type, NE

user or password of the NE according to the record.

Cause 3: The system control board on the NE is faulty.

1. Log in to the NE on the Web LCT. If you fail to log in, the system control board is

faulty. Reset the board. If the problem persists, replacing the SCC board.

Cause 4: If the NE has an OSC board, the fiber jumpers between OSC and FIU board are

faulty or the OSC board is faulty on the unreachable NE or on its opposite NE.

NOTE: The OSC board on the opposite NE of the unreachable NE reports alarms, such as LOS, LOF.

1. Check the fibers between OSC and FIU board. If the fiber jumper is dirty, clean it. If

it is faulty, replace it.

2. If the fiber jumper is good, the OSC board is faulty. Replace it.

Cause 5: The NE(non-first gateway NE) encounters system control board active/standby

switching.

1. No handling is required. Communication between the NE and U2000 will be restored

after the system control board active/standby switching.

Cause 6: Coherent and non-coherent boards are interconnected.

1. The DCN bytes are defined differently for coherent and non-coherent services, so the

two types of services cannot be interconnected. If DCN channels are unavailable,

check whether the interconnected boards are coherent boards.

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Very good read

good read, especially the beginners like me

Thank You Mr. Razzaq and Mr. Philander, much appreciated.

thanks for sharing, very descriptive to respond to a similar issue.

we have recently observed a similar case, where visibility was down of extended subrack of bws 1600G, upon visiting site it was observed etn LED was blinking as usual, also Ethernet cable was working fine. could you please address this issue?, would be thankful.

If Unreachability of one NE on U2000/NE Communication break, but service is normal
The main problems are the IP of NE can not ping to the U2000,
first we check the NE to gatewaym ping or tracert will solve about this

Hi Hieund, thanks for answering the query raised by Mr. zohaib.

Hi zohaib, you may switch GNE to the corresponding NE, to check it further.

Thanks for sharing