ters. An IP switch is a router that provides connection-oriented services in the IP layer. IP voice The routing of voice conversations over an IP-based network such as the Internet. Voice traffic has a low bandwidth requirement but requires very high QoS. IPDC (Internet Protocol Device Control) A specification that creates flexible manage- ment of media gateway devices. IPN (Interplanetary Internet) A network project that defines the architecture and proto- cols necessary to permit interoperation of the Internet resident on earth with other remotely located internets resident on other planets or spacecraft in transit. IPS7 (IP Signaling System 7) A signaling protocol that works with SS7. IPsec (IP Security) A set of protocols developed by the IETF to support secure exchange of packets at the IP layer. IPsec has been deployed widely to implement VPNs. IPT (IP telephony) The use of the Internet or a private IP network for telephony. IPTV (IP television) A system in which DTV is delivered to subscribers using Internet Proto- col over a broadband connection. IPTV is often provided in conjunction with VOD and Internet services such as Web access and VoIP. IPv4 (Internet Protocol version 4) The original generation of IP, in which an IP address has two parts: The first is the network ID and the second is the host ID. Under IPv4, there are five classes (Class A through Class E), which differ in how many networks and hosts are supported. IPv6 (Internet Protocol version 6) An IP addressing scheme that uses a 128-bit address, which allows a total of 340 billion billion billion billion unique addresses. IPv6 offers many ben- efits, but it requires a major reconfiguration of routers. Also called IPng (IP Next Generation). IPX (Internetwork Packet Exchange) IPX (Internetwork Packet Exchange) The Novell equivalent of IP. IPX is used to route NetWare packets between LANs. IPX does not guarantee the delivery of messages; NetWare's SPX protocol handles that task. IrDA (Infrared Data Association) A short-range wireless technology t