ICT vs H225
Please, can you recomment which one must be used in which situation - ICT vs H225 Trunk.
First of all, I know that the SRND talks about that, but that is more the theoretical one, whereas I need some real practical recommendation.
So the first thing that I have tested for differences between ICT and H225 Trunks:
All H323 connections are made between CUCM and CUCME, either directly or through gatekeeper or even CUBE.
Direct connect to from CUCM to CUCME.
ICT (Non-GK controlled) - Does not support Supplementary Services (like hold, transfer and etc) unless the MTP is checked. The CUCME Admin guide says to use this Trunk type to connect CUCM to CUCME and check the MTP on CUCM ICT Trunk.
H323 Gateway - when this type of H323 connection is made to CUCME, the CUCM IP phone support Supplementary Service even without the MTP checked.
Connect to CUCME through CUBE
H323 Gateway - "wait for far end H245 TCS" Unchecked. When using this type of connetion, I have enabled the "emptycapablility" command on CUBE, so that CUCM IP Phones could support Supplementary Service without MTP. While when using MTP checked, it does not matter any more whether the "emptycapablility" is enabled or not, the Supp Service are operational on CUCM IP Phones.
ICT (Non-GK controlled) - When using this type of connection to CUBE, CUCM IP Phones does not support Supplementary Services (even the "emptycapablility" is enabled on CUBE), until I check the MTP for this ICT.
Connect to CUCME using Gatekeeper
ICT (Gatekeeper-controlled) - I beleive, when using this type of connection, it has the same charasteristics as described already above for ICT Trunks. (Not Supp-service unless the MTP is used)
H225 Trunk (Gatekeeper-controlled) - I beleive, when using this type of connection, it has the same charasteristics as described above for H323 Gateway Type.
Based on that, can you please recommend, at least for the exam, which type of Connection has to be used for those kinds of H323 connectivity between CUCM and CUCME?