i’d go with MNoor solution first : try to reset or replace the dTRU. Most of the time, a really poor QoS is due to hardware issues.
Nick7 : you can perform a A-interface trace, and collect the IMSI’s which fail. You can even do it manually, it should be quite obvious. However, you should favor other assumptions than this one… you might be more succesful with a hardware check. Yet, a A interface trace will always lead you to the root problem in the end.
Da Architect : hello 🙂 what is the SCLD ?