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Reply To: E2E CSSR in ALU



As you suggested, the problem is probably focused on LU only. During Location Updates, the SDCCH is dropped.

Please please please, investigate this issue with traces and
1/ confirm the drops occur only during LU or IMSI ATTACH
2/ isolate the IMEI / IMSI of those mobiles
3/ see if there is a correlation (always same brands / models of phones, for example)

The E2E CSSR is great for this alternative use, as you did : you can isolate sd drops during call setup and sd drops during other procedures.

(note: i think these sd drops during LU are a worldwide issue, there are some threads about this in this forum… some ZTE phones seem to have some issues (based on older threads), but perhaps others too)
Have a good day,