This is again a strange problem. I have one IP phone using device pool A. This IP phone cannot place call but it can receive a call. I do a detailed trace on the phone, and the result is attached.
When I change the device pool to B, the problem resolved. The call processing is doing well. And when I change the device pool back to A, the problem appears again.
Device pool A and B is different in the CCM group.
It seems that there is a sort of cache in the primary Call Manager where the phone is registered.
Any explanation of why this happen ?
I really tired of the problems in Cisco IP Telephony infrastructure. Although the problems are not critical, but these problems really make me dizzy all the time. Fyuh..