Another approach, voice over multiservice broadband networks (VoMBN) also provides voice service (custom calling and Centrex services, as well as trunking for CPE), along with data services over the DSL from the regional broadband network—without requiring a Class-5 switch (See Topic 6). At the subscriber location, the equipment for VoMBN is very much like that for BLES. On the network side, however, a regional multiservice IP or ATM network, consisting of call signaling and processing servers and various gateway devices, replaces the Class-5, voice-switching network. This approach may be most cost-effective where the service provider wants to add voice services over an existing data network.

Figure 6. VoMBN Architecture