Hello everyone!
The case I will share with you today is about the problem that the 1800 device and the storage device cannot be connected.
Problem Description：
Here are two OSN 1800s, with device version: V100R003C01. Both OSN 1800s are equipped with ELOM (STND) boards. FC100 storage services are configured on TX1 / RX1 of the ELOM boards at sites A and B. The working mode used by ELOM (STND) is 1 * AP8 general mode. The port mode is ODU0 non-convergent mode, and then TX1 / RX1 is connected to the customer's storage switch.
The networking diagram is as follows:
Alarm: L_SYNC, REM_SF
Troubleshooting process：
1. Check the received optical power of the ELOM board. The received optical power of the RX1 port of the ELOM is about -7dB and the received optical power of the in-port is about -11dB. In addition, GE services on other ports are normal, eliminating optical power issues.
2. Set the external loopback on the TX1 / RX1 port of the ELOM board of the OSN 1800 device at site A. The optical port of storage switch 1 is normal and the indicator light is on. Then set the internal loopback on the IN / OUT port of the ELOM board to store The optical port of switch 1 is abnormal and the indicator is off.
Do the same operation at site B, the phenomenon is the same.
Because the probability of two ELOM boards at sites A and B being at the same time is relatively small, check the third reason
3. Check the customer storage switch configuration and find that the optical module of the switch is a multi-mode optical module that supports 1G, 2G, 3G, and 4G self-adaptation. At the same time, you can see the alarm of rate mismatch in the switch network management. Combined with the L_SYNC alarm reported by OSN 1800, it was determined that the speed of the optical module of the storage switch may not match the speed of the TX1 / RX1 optical module on the ELOM board;
So let the customer set the speed of the optical port of the storage switch to 1G (previously adaptive mode). After both sites A and B did the same operation, they found that the optical port of the storage switch was normal and the service test was normal.
Root cause：
The causes of the failure are:
1. The received optical power of the board may be abnormal.
2. The board is faulty and cannot receive data.
3. The working mode, type of signal or rate of the peer device is inconsistent with the configuration of the station.
