Hi experts,

Hope you can help me on this.

SGW is sending a delete bearer to MME (due to a bearer idle timeout parameter).
Upon receiving this bearer deletion, MME informs the MSC with IMSI Detach on SGs.

Now the MSC knows that if there is a Mobile Terminating Call, MSC needs to page the UE in 2G or 3G, through A or IuCS.

The problem is that the UE is still attached to 4G and so the UE doesn't seem to answer to the 2G/3G paging (I did the tests with 3 types of phones)

Isn't MME supposed to tell the UE to fallback to 2G or 3G, at the same time it sends IMSI Detach to MSC ?

If not, how should it work ?


Best regards,

Thierry K.