Problem Description

Our OSN1500 equipment newly expanded a SSN2EFT8 single board and ZTE Ethernet board docking to open the Agricultural Bank of China's large customers circuit. After adding the single board network management and configuring the service, we found that it is not possible to dock with ZTE, and the OSN1500 's EFT8 single board and ZTE's Ethernet board are directly hung between the portable machine for the ping test, and the result is still not possible to ping.

Alarm Information

There is no alarm in the network management.

Processing

After troubleshooting, it was found that:
1, the service configuration is correct, and the time slots at both ends of the docking are correct according to the 3-7-3 mode.
2, the port modes are 100M full-duplex.
3, ZTE checked that their Ethernet data configuration is correct.
There is no alarm on the network management, and there is no problem with the service configuration, but the ping is not available. At this time, I noticed that the EFT8 that was normally used in the network before was SSN1EFT8 and the new expansion was SSN2EFT8, but there was no difference. Doubt N2 single board has any restrictions, through the collection of data sent to the R & D analysis, found that the packet is in the single board decapsulation module is discarded, so the focus of suspicion of this module has a problem, will be the module to collect all the registers out of the comparison, found that the N1 and N2 single board the following register differences, and ultimately proved that docking can not be the reason is that the N2 single board GTP checksum is too strict.

Root cause

After checking, it is found that this OSN 1500 device has an EFT8 single board in use before, and it is interoperable with the ZTE device. For the new expansion of this EFT8 single board, the following reasons are analyzed:
1. Is there any problem with the service configuration, because there is a difference between the interpolation mode and the sequential mode in terms of time slot docking. 2.
Whether the Ethernet port negotiation mode is consistent
3. The EFT8 board is a pure pass-through Ethernet board, and whether ZTE's Ethernet board is correctly configured with VLANs

Suggestions and Summary

Solution
1. Modify the encapsulation mode of docking to LAPS
2. ZTE modifies the sent GFP type to 0x1001, and the HEC checksum value of Type field to 0x1352
3. Apply for OSN1500 SSN1EFT8 to the customer, and replace the SSN2EFT8 which is not able to be docked. R&D informs the customer that the software of single board will be modified later to modify the checksum value of the GFP of N2 single board to be the same as that of N1. The R&D told us that we will modify the single board software to modify the GFP checksum of N2 single board to be the same as that of N1.