Customer changed frequency of NSN to the same with ZTE and they enable Iur, the CSSR degraded so much so they disable the Iur and CSSR came to normal.
CSSR:
I've checked the CT files from 12:00 to 12:30 7th Sept
All RAB assignment failures are caused by Iur interface
After RAB assignment request received, there was RL reconfiguration failure with cause: "invalid CM settings"
GAP pattern sequence n=4, but NSN only can support n=3
Basically, we should show the analysis to customer and push NSN to solve the issue with customer together
Final solution, we have one parameter to avoid this issue
But after modifying this parameter, Voice DCR would be degraded