Description of the problem

On the night of March 24, 2011, capacity expansion was added to NE1250 between NE1228 and NE1229, and when using TCAT tool, it was found that there were stays and delays in issuing commands, and in the end, the commands were not issued successfully, and the software automatically backed up, and the service was not affected. The current network equipment version is Huawei SDH equipment OSN3500V2R11C00SPC200 (5.21.31.35), and the network management version is U2000V100R002C00SPC003, and the TCAT tool and the network management version are V100R002C00SPC003.

Processing

Analyze the reasons for the stay and delay of the commands issued by the TCAT tool: First, it is possible that the tool, the network management and the mutual matching problem; second, it is possible that the pipeline side of the command issue, that is, the DCN communication problem; third, it is the problem of the main control of the device that leads to the response timeout. Separately analyzed as follows:

1, check the supporting relationship between the tool and the network management is OK, change a portable machine to install the tool and the network management supporting the use of the same problem still exists. Can initially rule out the problem of the tool network management.

2, due to the TCAT tool for capacity expansion operations need to be added to the new network element to issue a new tunnel command, especially when the number of new network elements through a larger number of tunnel, issued more new commands, need to ensure that the network DCN communication is normal. From NE1228 and NE1229, respectively, check the DCN settings of the passed network elements along the direction of the gateway network element, and there is no parameter setting error. From the network management ping NE1228 and NE1229 network elements respectively, there is no problem. ping NE1250 network element found that there is a probability of packet loss and response timeout phenomenon. After investigation, it is found that NE1228 and NE1229 belong to different gateway network elements, NE1201 and NE1205, respectively, and NE1250 was accessed through the ECC channel of the SDH network by the local staff to set its gateway network element as NE1203 before the expansion, which leads to the fact that NE1250 does not belong to the same gateway network element as NE1228, nor does it belong to the same gateway network element as NE1229. The NE1250 does not belong to the same gateway element as the NE1228 nor the NE1229. After changing the gateway of NE1250 to NE1201, the above phenomenon disappears when pinging NE1250 again.

Check the operation status of NE1228, NE1229 and NE1250 and the efficiency of the master control in uploading the data of the backup network element, and initially determine that the response of the master control is normal.

Set the newly added network element as belonging to the same gateway network element as the neighboring network element, and test the DCN communication through the ping command. After ensuring that there is no probability of packet loss and response timeout when pinging the NE1250 network element, and after cleaning up the discrete tunnel caused by the previous expansion failure, the TCAT tool is used again to disassemble the ring and add points, and the operation is carried out smoothly.

Root Cause

Incorrect gateway settings, resulting in abnormal DCN communication

Solution

After analyzing the problem and focusing on the DCN communication issue, after ensuring that there is no probability of packet loss and response timeout in pinging NE1250 network elements, and cleaning up the discrete tunnel caused by the previous expansion failure, the TCAT tool is used again to disassemble the ring and add points, and the operation is carried out smoothly.

Suggestions and Summary

Before capacity expansion, it is recommended to conduct a health check on the DCN settings of the entire network, including the settings of gateway network elements, the settings of backup gateways, DCN communication bandwidth and combing of anomalies. Then pay attention to cleaning up the discrete tunnel that exists in the existing network to ensure that the discrete tunnel that exists does not affect the tunnel that needs to be penetrated by the expanded network elements in the existing network.

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