at- tery) when the called number answers. anycast In IP routing, the point-to-point flow of packets between a single client and the near- est destination server identified by an anycast address. Anycast involves a one-to-many associa- tion in which each destination address identifies a group of receivers; at any given time, only one of them is chosen to receive information from any given sender. AODV (Ad Hoc, On Demand, Distance Vector) The leading protocol for routing data across wireless mesh networks. It is designed with mobile wireless devices in mind. It is in the public domain and is therefore subject to no copyright protection. API (application programming interface) A set of routines that an application program uses to request and carry out low-level services performed by the operating system. Apple Talk Apple Computer's set of specifications for connecting computers and other devices to share information over LANs. It describes network hardware, software, and protocols and lets an assortment of Mac and non-Mac devices communicate over a variety of transceivers and com- munications media. application (1) Software with which the user interacts. (2) The use to which a system is put (e.g., e-mail, videoconferencing, high-speed data access, network management). application layer Layer 7 of the OSI model, which enables users to transfer files, send e-mail, and perform other functions that involve interaction with network components and services. application-layer multicasting A technique that ensures that just one stream goes across the backbone whenever possible. application program A software program that contains no I/O coding (except in the form of macro instructions that transfer control to the supervisory programs) and is usually unique to one type of application. architecture The physical interrelationship between the components of a computer or a network. area code A three-digit code designating a toll center that is not in the NPA of the calling party. restriction The capability of switching equipment