Huawei:: Abnormal FR traffic increamen

Dear All

Hope things are fine.

I’m facing a from in my huawei 2G network as of below.

Suddenly in some sites FR traffic increased abnormally (10erl to 30erl) resulting high CDR (1% to 12%). TCH assign success rate becomes very poor which gives a clear indication towards faulty HW/Interference. HW replacement does not improve situation as well as frequency changing resulted same.

If we lock the TCH TRX CDR decreases. BCCH TRX is not affected a bit. Same thing happens for all affected sites.

We are suspecting that someone is using VOIP in that site.

We adjusted all the traffic related parameters but failed to shift traffic to HR.

How can i cope this problem of high CDR.
If some VOIP is actually being used, what actually is happening for this site ??

Waiting for your replies.

MS