My advise for any greenfield installation is to use CUCM; however, it does not fully replace VCS, nor is it expected to in the near future. A few examples:
- VCS Control is still the recommended call control product for non-Cisco video clients (e.g. Polycom, Sony, generic H.323, etc). This also remains the case for other types of interop (e.g. IPv4 to IPv6).
- VCS Control is still required for the Ascend/H.460 firewall travesal to work with VCS Expressway. Any Internet-facing call would go CUCM --> VCS-C --> VCS-E --> Internet.
- VCS Expressway is still required for any non-AnyConnect capable client located on the internet to register; CUCM is not intended to be directly Internet facing.
CUCM is Cisco's flagship call control platform and it will be the default design choice unless a specific requirement arrises that rules it out. Perhaps if the customer does not have Cisco UC today and never ever will (which seems unlikely frankly), you may be able to justify a VCS-only approach. The days of a siloed video-enabled infrastructure seem numbered though.
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