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The Alarm Is Given on the Low Optical Power Received by eSFP After the NE80E is upgraded to V300R002C06B325

Publication Date:  2012-07-27 Views:  86 Downloads:  0

Issue Description

A POS board gives an alarm on the low optical power received by the eSFP after the NE80E is upgraded fromVRP5.30 310032.08 toV300R002C06B325. 

Alarm Information

<SND_NE80e>disp alarm all
Level Date Time Info

Warning 08-05-13 10:51:21 LPU6 is failed, esfp on card 0 port 1 re
ceive power too low , maybe fiber not plu
gged !
May 13 2008 06:21:21 SND_NE80e %%01SRM/4/ESFP_RXPOWER_LOW(l): Slot6 PIC0 Port1 E
SFP RxPower too low ,maybe fiber not plugged !
May 13 2008 06:01:21 SND_NE80e %%01SRM/4/ESFP_RXPOWER_NORMAL(l): Slot6 PIC0 Port
1 ESFP RxPower normal! 

Handling Process

1. Log in to the device, the engineer checked the information about POS 6/0/1:
<SND_NE80e> disp interface Pos 6/0/1
Pos6/0/1 current state : UP
Line protocol current state : UP
Description : RIF_NE40e_V_2/0/0, Route Port
The Maximum Transmit Unit is 4470 bytes, Hold timer is 10(sec)
Internet Address is ***.***.160.125/30
Link layer protocol is PPP
LCP opened, IPCP opened, MPLSCP opened
The Vendor PN is QFCT-5737TP
Port BW: 2.5G, Transceiver max BW: 2.5G, Transceiver Mode: SingleMode
WaveLength: 1310nm, Transmission Distance: 15km
Physical layer is Packet Over SDH,
Scramble enabled, clock master, CRC-32, loopback: none
Flag J0 "NetEngine "
Flag J1 "NetEngine "
Flag C2 22(0x16)
SDH alarm:
section layer: none
line layer: none
path layer: none
SDH error:
section layer: B1 2
line layer: B2 0 REI 0
path layer: B3 0
Statistics last cleared: 2008-05-13 04:16:24
Last 30 seconds input rate 26362664 bits/sec, 15488 packets/sec
Last 30 seconds output rate 1243672 bits/sec, 746 packets/sec
Input: 160072405 packets, 34039160680 bytes
Input error: 0 shortpacket, 0 longpacket, 0 CRC, 0 lostpacket
Output: 6947605 packets, 1446884042 bytes
Output error: 0 lostpackets
The interface ran normally, and thus the first reason was excluded. The engineer noticed the count at B1.
(B1 is used to monitor the error code at the re-generated section layer. It checks the STM-N frame and collects the counts when the received optical power is too low). This was why the alarm was generated.
2. Check the actual optical power at the interface in hidden mode.
[SND_NE80e-hidecmd]sfp-debug 6 0 1
external Cal Rx Power : -22.22 (dBm)
external Cal Laser Bias I : 12.24 (mA)
external Cal Tx Power : -2.78 (dBm)
external Cal Temperature : 34.10 (C)
external Cal Voltage : 3.35 (V)
The optical power actually received is lower than the receiving sensitivity of the eSFP, that is, 21 dbm. This is the reason why the alarm is generated.
The V300R002C06B325 version allows the user to check the optical power at the POS interface through a specific command. This function facilitates the fault location. 

Root Cause

Because the power detection function is enabled on the eSFP, (for the information about the eSFP, refer to SC0000242454), the similar function is enabled on the relevant software of V300R002C06B325. Alarms are given for the low optical power at the interface. Through the initial assessment, the causes may be:
1. The eSFP is in place, but the fiber is not plugged.
2. The optical power actually received is lower than the receiving sensitivity of the eSFP. In this case, the alarm is normal.