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Reply To: What type of call drop is this?


Thanks pix,

Let us say Nokia cell= N1

Ericsson cell= E1

Today I did the following testing.

I have two MS , say MS1 and MS2

I initiated a call from MS1 to MS2 in N1

The call gets established.
In the Current channel window

I can see the ciphering through A5/2.

Then a handover occurs to E1 (This is an inter MSC handover)

The handover is successful but one strange thing i observed.

I see that even though the ciphering is disabled in the whole Ericsson MSC, yet the current channel window displays that ciphering in on with A5/2 in E1, that was strange.

With in seconds the call gets dropped rather released at MS2.

But MS1 continues to show the dedicated mode parameters to me in E1 cell.

We might confuse the case with call muting, but strictly speaking I don’t think it is a case of call muting actually the call at MS2 has been released, I repeat it is not dropped at MS2.

But the call at MS1 is not release and the MS1 is continuing to show he dedicated mode parameters, and of course the ciphering in a cell which doesn’t support it at all.

This is a stage where MS1 can be termed as in hang state.

Even if you press the END at MS1 the only difference it will make is that the indication of off hook will be removed from the display of MS but the call/TS is still shown as occupied.

The reverse is not true, I mean you initiate a call in E1 and if the same is handover to N1 i.e from a cell where ciphering is off to a cell where cell ciphering in on, such scenario doesn’t happen

But again if the call is handed over back to E1 the process repeats.

As per the suggestion of Pix,

I requested the NSS to enable the ciphering in E1 or rather MSC (as ciphering is a feature at MSC level?)

After that the same testing was repeated. But the situation remained unchanged.

After that the NSS person (ericsson) requested that we might test again by disabling the ciphering in both the MSCs i.e. Nokia and Ericsson.

And we did so to test it again. But again this times also no result.

Finally we made the situation back to initial i.e. in N1 it enabled but in e1 it is disabled.

After that I asked about DTX. They said in both the cells it is on.

In N1 SDCCH handover was enabled, that was disabled.

But we are back to the square.