I'm using a CUCM 6.1 Demo version(with the 50DLU Demo)
So we use a prototyp lab that interconnect a CCM, a Voice Enabled router,a pix Firewall, an edge router and a distant voip call.
We can make call in each direction,i.e from CCM to Voip, from Voip to CCM.
We've configured all parameters in the CCM, such as devicepool,region,MTP,MRG, MRGL, SIP Trunk with MTP required checked.
We've configured an MTP in the router.
And now this is the problem:
If the call is from the outside (voip) to the inside, it can be transfered with internal phone (ipphone to ip phone), and parked.
If the call is from the inside to voip, it cannot be transfered.
I explain :
there is two ipphone 4001 and 1010.
The distant phone is 3001.
If I call from 3001 to 4001, 4001 can transfer it to 1010.
If I call from 4001 to 3001, and after 4001 transfer it to 1010. The call is not transfered.
In 3001 I hear bipbipbip (3 bip) (ToH) when i push the transfer button in 4001 to transfer to 1010.
After i've composed 1010, 1010 ring and I take the call from 4001.
After, i push the transfer button in 4001.
So, instead of displaying the number 3001, the number 4001 is displayed on the phone 1010.
The channel call to 3001 is lost somewhere.
Otherwise, if the call is parked, then 1010 can take it.
Have you any issues than parking call?
The call manager is a 18.104.22.1680-3
The network schema is in the attachements.