Description of the problem

The recovery time for the two cross-single boards, GXCS and SXCS, to re-power up and resume work after a power down is different, about 3 minutes for GXCS and about 8 minutes for SXCS.

Processing

Condition: The crossover is able to recover all correct crossover configuration data from flash

1. The size of the crossover matrix array due to the crossover capacity.

GXCSA as 40G high-order and 5G low-order crossover board, and SXCSB as 240G high-order and 20G low-order crossover board, in the crossover matrix saving space SXCSB high-order is 6 times of GXCSA, SXCSB low-order is 4 times of GXCSA, and if saving the crossover matrix to the retained memory needs to be saved in two copies (mfs and ofs1), then saving space SXCSB high order is 12 times that of GXCSA and SXCSB low order is 8 times that of GXCSA. Therefore, the amount of data is large, the recovery is slow, and after power-down startup, when the cross-matrix is recovered, the process of CRC checking of the configuration file, reading of the high-order and low-order cross-matrices, correctness checking, recovering to the memory, and writing to the chip registers all take many times longer than the time spent on GXCSA. This calculation shows that the average time to restore the configuration SXCSB is 2.5 times longer than that of GXCSA.

2. Dynamic cross-bus rate.

The crossover chip used in GXCSA is a fixed bus rate, while the crossover chip used in SXCSB is a dynamic bus rate, so according to the business veneer inserted in each slot, it is necessary to set the corresponding bus rate of each slot to 622M or 2.5G. Therefore, after a power failure, the SXCSB needs to wait for the master board to send down the bus rate of each slot, whereas the GXCSSA is a fixed bus rate and doesn't need to wait for the master to send down the bus rate, which also affects the service recovery time of SXCSB. The GXCSA has a fixed bus rate and does not need to wait for the master to issue the bus rate, which also affects the recovery time of the SXCSB after a power failure.

Condition: The crossover is not able to recover all the correct crossover configuration data from flash.

Possible reasons for not being able to recover correct cross configuration data from flash

1. Crossover writing memory data to flash is a cyclic task, and this cycle is about 1 hour. If the modified crossover configuration time is in the middle of two cycle intervals, then the newly modified configuration cannot be saved. Thus, the correct crossover configuration cannot be recovered from flash.

2.Recovering data from flash cannot recover data correctly due to other reasons.

In these scenarios, the service recovery time is the same. All of them need to wait for the master control board to start work and then issue the correct cross-configuration before the service can be recovered.

Root Cause

Matrix information not saved to flash.

Solution

If you want to solve the problem of preventing part of the cross configuration data from being lost when power is dropped, you can issue the cfg-backup-bdcfg command after configuring the data to save the current memory data to flash. Refer to support case SC0000660458.

The technical information related to this chapter and the SDH equipment troubleshooting process are collected and organized by Shenzhen Optical Transmission Network Technology Co.(www.opticaltrans.com), please retain! Our company specializes in Huawei SDH optical transmission equipment,SDH transmission equipment sales.