Integrated Access Device (IAD)

An Integrated Access Device or IAD is a customer premise device that provides access to wide area networks and the Internet. Specifically, it aggregates multiple channels of information including voice and data across a single shared access link to a carrier or service provider POP (Point-of-Presence). The access link may be a T-1 line, a DSL connection, a CATV network, a broadband wireless link or a metro-Ethernet connection.

At the POP, the customer's aggregated information is typically directed into a multiservice provisioning platform (MSPP) which is a complex and expensive device that sits between customers and the core network. It manages traffic streams coming from customers and forwards those streams to the PSTN (Public Switched Telephone Network) or appropriate WAN (Wide Area Network e.g. ATM, FR or the Internet).

IADs have multiple functions, including T-1 service, security protection via firewalls, a point for remote monitoring, routing and frame relay access. IADs that are based on ATM (Asynchronous Transfer Mode) technology provide dynamic bandwidth allocation on the T-1. Dynamic bandwidth allocation dynamically shifts traffic on the T-1 so that customers don't have to permanently allocate a set number of channels for voice or data. If there are only five channels used for voice, the IAD automatically uses the rest of the "pipe" for data. However, if a sixth outgoing or incoming call is placed, data is shifted to the other channels. Traffic is dynamically reallocated within the entire T-1's capacity. Therefore, the customer uses the T-1 line more efficiently by, for example, having more capacity for data during times of the day or night when voice traffic is low.

CLECs (Competitive Local Exchange Carriers) were the first telephone companies to offer IADs to small organizations. This innovation greatly increased the affordability of T-1 for small customers by eliminating the need for a separate broadband connection for Internet access in addition to voice lines. RBOCs (Regional Bell Operating Companies) and smaller incumbents later adopted this strategy. Integrated access for voice and data on one T-1 benefits telephone companies that only need to provision a single four-wire (two-pair) copper line or fiber rather than multiple copper pairs for voice and data.