On-premise UC solution is built/owned by the cooperation IT department, which has the servers physically located on site of enterprise, the products of UC solution are operated and managed by enterprise itself. Typically, on-premise UC solution is based on VoIP PBX platform with additional UC applications added to provide UC required functions. It will rent the T1/E1 trunk or SIP trunk to connecting to telephony network for off-net call.
Vendors include Cisco, Avaya, Siemens, Alcatel-Lucent, ShoreTel, etc. Most of these products are evolved from TDM based PBX products, also each vendor have their product specific design and interface.
IP Multi-media Subsystem (IMS) is defined by various standard body include 3GPP, TISPAN, etc. It’s a fully standardized architecture with detailed definition of interface/protocol/procedures. It’s a platform enabler facilitating a multi-tenant environment, including residential users, wireless users and enterprise UC users.
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