IBM SAN16B-2 User Guide - Page 77

host bus adapter (HBA). The interface card between a server or workstation bus and the Fibre Channel network. hot-pluggable. A field replaceable unit (FRU) that can be removed or installed without turning the system off. Also called ″hot swappable.″ hot swappable. See hot-pluggable. HTTP. See Hypertext Transfer Protocol. hub. A Fibre Channel device that connects nodes into a logical loop by using a physical star topology. Hubs will automatically recognize an active node and insert the node into the loop. A node that fails or is powered off is automatically removed from the loop. Hypertext Transfer Protocol (HTTP). In the Internet suite of protocols, the protocol that is used to transfer and display hypertext and XML documents on the Web. I ID. Identification. idle. Continuous transmission of an ordered set over a Fibre Channel link when no data is being transmitted, to keep the link active and maintain bit, byte, and word synchronization. in-band. Transmission of management protocol over the Fibre Channel. initiator. A server or workstation on a Fibre Channel network that initiates communications with storage devices. See also target. in-order delivery (IOD). A parameter that, when set, guarantees that frames are either delivered in order or dropped. Internet protocol (IP). A protocol that routes data through a network or interconnected networks. Internet Protocol (IP) acts as an intermediary between the higher protocol layers and the physical network. inter-switch link (ISL). A Fibre Channel link that connects two switches (a link from the expansion port (E_port) of one switch to the E_port of another). IOD. See in-order delivery. IP. See internet protocol. ISL. See inter-switch link. ISL Trunking. A feature that enables distribution of traffic over the combined bandwidth of up to four inter-switch links (ISLs) (between adjacent switches), while preserving in-order delivery. A set of trunked ISLs is called a trunking group; each port employed in a trunking group is called a trunking port. See also master port. isolated E_port. An expansion port (E_port) that is online but not operational between switches due to overlapping domain ID or nonidentical parameters such as error delay timeout values (E_D_TOVs). See also expansion port. J JBOD. Just a bunch of disks. K K28.5. A special 10-bit character used to indicate the beginning of a transmission word that performs fibre channel control and signaling functions. The first seven bits of the character are the comma pattern. See also comma. kernel flash. Flash memory that stores the bootable kernel code and is visible within the memory space of the processor. Data is stored as raw bits. key. A string of data (usually a numeric value) shared between two entities and used to control a cryptographic algorithm. Usually selected from a large pool of possible keys to make unauthorized identification of the key difficult. See also key pair. key pair. In public key cryptography, a pair of keys consisting of a public and private key of an entity. The public key can be publicized, but the private key must be kept secret. L LAN. See local area network. latency. The period of time required to transmit a frame, from the time it is sent until it arrives. LED. See light-emitting diode. light-emitting diode (LED). An electronic component that gives off visible or infrared light when electricity is passed through it. It is used to indicate the status of elements on a switch. link. As applies to fibre channel, a physical connection between two ports, consisting of both transmit and receive fibers. See also circuit. link services. A protocol for link-related services. LIP. See loop initialization primitive. LM_TOV. See loop master timeout value. Glossary 55