rsion of HiperLAN, called HiperLanl, was designed to provide faster data rates than the IEEE 802.11 standards. The second version of the standard, HiperLan2, will give consumers wireless access to the Internet and future multimedia, as well as real-time video services, at speeds of up to 54Mbps. HiperMAN (High-Performance Radio MAN) A fixed wireless access network standard for operating between 2GHz to 11GHz that is aimed at providing a broadband wireless solution for metropolitan area networks. HIPPI (High-Performance Parallel Interface) A gigabit-per-second OSI Layer 1 and 2 interface standardized by ANSI. HIPPI supports 800Mbps up to 82 feet (25 m) using a 32-bit par- allel copper connector and can be extended up to several miles/kilometers by using fiber-optic technology. A higher-speed option uses 64 parallel lines to support operation at up to 1.6Gbps. HMIPv6 (Hierarchical Mobile IPv6) An enhancement to the Mobile IP technique that is being developed to improve mobile communications in certain circumstances by making the processes more secure and more efficient. holding time The length of time a communications channel is in use for each transmission. The holding time includes both message tone and operating time. Also called connect time. HomeRF An open standard for short-range transmission of digital voice and data between mobile devices. Glossary hop A unit of network distance. The number of hops between a source and a destination is the number of nodes between them (e.g., number of routers between hosts on the Internet). hop-by-hop retransmission A system in which an intermediate device retransmits so that the retransmission travels a shorter path over a fewer number of hops and is therefore less delayed. horizontal distribution frame A hub for terminating cables run on a floor. host An end-user computer system that connects to a network. Hosts range in size from PCs to supercomputers. host interface The link between a communications processor or network and a host computer. host system (1) The computing