Description of the problem

A local operator's ASON network consists of OSN3500 devices, the device host version is 5.21.18.50, and the T2000 network management version is V2R7C03. After the network has been put into use for a period of time, the customer feedbacks that some of the network elements report the CP_LSP_SIG_EXCEPT alarm, and finds that the returnable silver-level intelligent circuits related to the alarm are in rerouting state in the intelligent circuit management view. In the intelligent circuit management view, it is found that the returnable silver-level intelligent circuit associated with the alarm is in the rerouting state, and it is still unable to return to the original service path after the original routed optical paths are restored.

Alarm Information

CP_LSP_SIG_EXCEPT

Processing

Delete the redundant services of the source and host node network elements of the intelligent circuits so that the number of their SNCP service pairs is less than 1121, the alarm disappears automatically, and the corresponding intelligent circuits return to their original paths automatically, and the problem is solved.

Root Cause

Initially, it was suspected that the original routing time slots of these intelligent circuits were insufficient, resulting in the failure of intelligent services to return, but it was found that the resource utilization rate of the corresponding optical circuits was less than 50%, and the possibility of insufficient time slots was ruled out. The data of the source and host nodes of the problematic circuits were collected and returned to the company for analysis, and the causes of the problem were found to be as follows: The hardware model of the cross board of these OSN3500 intelligent network elements is SSN1SXCSA01, which can support up to 1,184 SNCP pairs, and since the intelligent network elements need to reserve 63 SNCP pairs to be used in the calculation of the rerouting, the maximum number of protection pairs the equipment can use is 1,184-63=1,121. is 1184-63 = 1121. Logging in to the network element under :cfg-get-sncppg we can see that the

PG-ID REVERT-MODE ACTIVE-FLAG

1 norvt active

2 norvt active

3 norvt active

1176 norvt active

1177 norvt active

Total records :1124

In other words, the number of SNCP protection pairs existing on the network element is 1124, which exceeds the limit of 1121 and eventually leads to LSP signaling anomalies.

Suggestion and Summary

For sites with similar issues, it is recommended to directly replace the IXCSA cross boards, which support up to 2016 SNCP protection pairs and can effectively circumvent the issue.

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