92 bits, and 256 bits. agent Software that processes queries and sends responses on behalf of an application. agnostic device A device that supports multiple data protocols (e.g., IP, Frame Relay, ATM, MPLS) and supports multiple traffic types, such as voice, data, and video. AIN (advanced intelligent network) The second generation of intelligent networks, neered by Bellcore (which is now Telcordia). An AIN is a service-independent network architec- AIP (application infrastructure provider) ture that enables carriers to create and uniformly support telecom services and features via a common architectural platform, with the objective of allowing for rapid creation of customizable telecommunication services. AIP (application infrastructure provider) A provider that manages center serv- ers, databases, switches, and other gears on which applications run. air interface A term used in mobile communications to refer to the radio frequency portion of the circuit between the mobile station and the base station. A-law encoding Encoding, according to ITU-T Recommendation G.711, that is used with European 30-channel PCM systems that comply with ITU-T Recommendation G.732. It employs nonuniform quantization to obtain the desired compression characteristic. alerting signals The ringing tones, busy tones, and any specific busy alerts used to indicate network congestion or unavailability. alternate routing Routing of a call or message over a substitute route when an established route has failed, is busy, or is otherwise unavailable for immediate use. AM (amplitude modulation) Varying of a carrier signal's strength (amplitude) depending on whether the information being transmitted is a 1 bit or a 0 bit. ambient noise Communications interference that is present in a signal path at all times. AMC (Adaptive Modulation and Coding) A technique used in HSDPA that allows the modulation and coding schemes to be determined dynamically, depending on the conditions of the wireless channel at that time. AMI (alternate mark inversion) An enc