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FDDI. Fiber Distributed Data Interface. A set of American National Standards Institute (ANSI) protocols for sending digital data over fiber optic cable. FDDI networks are token-passing networks, and support data rates of up to 100 Mbps (100 million bits) per second. FDDI networks are typically used as backbones for Wide- Area Networks (WANs).

Filer. An appliance that attaches to a computer network and is used for data storage.

Gateway. A computer that acts as an intermediate device for two or more networks that use the same protocols. The gateway functions as an entry and exit point to the network. Transport protocol conversion might not be required, but some form of processing is typically performed.

Gigabit Ethernet. An Ethernet technology that raises transmission speed to 1 Gbps (1000 Mbps).

Hashing. Producing hash values for accessing data or for security. A hash value, is a number generated from a string of text. The hash is substantially smaller than the text itself and it is generated by a formula in such a way that it is extremely unlikely that some other text will produce the same hash value.

Heartbeat. A repeating signal transmitted from one appliance to another that indicates that the appliance is operating.

Heuristic. A method of problem solving using exploration and trial and error methods. Heuristic program design provides a framework for solving the problem in contrast with a fixed set of rules (algorithmic) that cannot vary.

Host. A computer or other computing device that resides on a network.

Host address. The IP address assigned to each computer attached to the network.

Host name. Name given to a computer, usually by DNS.

HSRP. Hot Standby Routing Protocol. HSRP is a routing protocol from Cisco that provides backup to a router in the event of failure. Using HSRP, several routers are connected to the same segment of an Ethernet, FDDI or token-ring network and work together to present the appearance of a single virtual router on the LAN. The routers share the same IP and MAC addresses, therefore in the event of failure of one router, the hosts on the LAN are able to continue forwarding packets to a consistent IP and MAC address. The process of transferring the routing responsibilities from one device to another is transparent to the user.

HTTP. Hypertext Transport Protocol. The protocol used by Web browsers to communicate with Web servers.

HTTPS. Hypertext Transport Protocol Secure. The protocol for accessing a secure Web server. Using HTTPS directs the message to a secure port number to be managed by a security protocol.

Interface. The point at which a connection is made between two elements, systems, or devices so that they can communicate with one another.

GLOSSARY