In the access network interconnection test of a customer, alarms related to GFP encapsulation are reported in the Ethernet boards of both Huawei and company A after the initial configuration and the Ethernet service cannot be interconnected.
Board and version of company A: 1660 Board - ISA ES 4 8 FE Ver. 1.02.65.
Huawei equipment: OptiX OSN 2500, 184.108.40.206P02, SSN1EFS4
GFP encapsulation parameters:
The GFP parameter of the board of company A that the Huawei board can correspond to includes only the FCS enable/disable. The parameter is set to disable by field engineers.
The GFP encapsulation parameter of the Huawei VCG is as follows:
In compliance with the normal interconnection principle, the field engineers disable the LCAS function of the boards at the two sides and configures only one VC-12 member for the VCG to improve the interconnection success ratio.
Alarm in the equipment of company A: GFP TSF
Alarm in the Huawei EFS4 board: VCTRUNK port, ALM_GFP_dLFD
Based on the preceding analysis, it can be concluded that the interconnection failure is caused by the K4 byte. The field engineers enable the LCAS in the Ethernet boards of Huawei and company A. As a result, the GFP alarm clears, the service interconnection succeeds, and the 1xVC-12 or 5xVC-12 is normal.
The VC function of the Huawei Ethernet board works normally no matter whether the LCAS function is disabled or enabled. However, when the LCAS is disabled in the Ethernet board of company A, only one member can be configured for the VCG.. Hence, the engineers doubt that the Ethernet board of company A has certain restrictions on the use of VC; That is, to use the VCG, the LCAS function must be enabled.
No information on the GFP TSF alarm is available for analysis. The ALM_GFP_dLFD alarm is caused by the interconnection of VCG members, such as inconsistent member quantity or error bits in the members. The field engineers check the performance and find no error bits in the VC-12. Hence, the ALM_GFP_dLFD can be caused only by VCG members. However, because only one VC-12 is used, it is less possible that the problem is directly caused by the VC-12.
Then, the field engineers communicate with the customer in the field and learn that the Ethernet board of company A can interconnect with the Ethernet board of company N. The engineers check the configuration and find that the LCAS function is enabled in the VCGs of the Ethernet boards of both company A and company N.
The LCAS uses the same K4 byte for the VC-12 level VCG as the overhead byte used in the virtual concatenation. The purpose of the K4 byte is to indicate the virtual concatenation member.
In the interconnection with the Ethernet board of company A, if the GFP TST alarm is generated in the Ethernet board of company A and the ALM_GFP_dLFD is generated in the Huawei Ethernet board, engineers should enable the LCAS function in the two ends. Engineers should refer to the symptom description for the configuration of other GFP parameters. It should be specially noted that the FCS parameter must be set to NO.