Cisco Systems Cisco IOS XR manual Examples of platforms using a GUI. See also CLI, GL-4

Glossary

forwarding

FRR

FTP

Process of sending a frame toward its ultimate destination by way of an internetworking device.

fast reroute. Automatically reroutes traffic on a label switch path (LSP) if a node or link in an LSP fails. FRR reduces the loss of packets traveling over an LSP.

File Transfer Protocol. Application protocol, part of the TCP/IP protocol stack, used for transferring files between network nodes. FTP is defined in RFC 959.

G

GE	Gigabit Ethernet. Standard for a high-speed Ethernet, approved by the IEEE 802.3z standards committee
	in 1996.
Gigabit Ethernet	Standard for a high-speed Ethernet, approved by the IEEE 802.3z standards committee in 1996.
GUI	graphical user interface. A user environment that uses pictorial and textual representations of the input
	and output of applications and the hierarchical or other data structure in which information is stored.
	Such conventions as buttons, icons, and windows are typical, and many actions are performed using a
	pointing device (such as a mouse). Microsoft Windows and the Apple Macintosh are prominent
	examples of platforms using a GUI. See also CLI.

H

HA	High availability is defined as the continuous operation of systems. For a system to be available, all
	components, including application and database servers, storage devices, and the end-to-end network,
	need to provide continuous service.
HDLC	high-level data link control. ISO communications protocol used in X.25 packet-switching networks.
	HDLC provides error correction at the data link layer and contains the following subsets: LAPB and
	SDLC.

hexadecimal

hop

hop count

HTTP

A number system having 16 as its base. This number representation uses the digits 0–9, with their usual meaning, plus the letters A–F (or a–f) to represent hexadecimal digits with values of (decimal) 10 to 15. The far right digit counts ones, the next counts multiples of 16, then 16^2 = 256, and so on.

Hexadecimal is more succinct than binary for representing bit masks, machines addresses, and other low-level constants but it is still reasonably easy to split a hex number into different bit positions. For example, the top 16 bits of a 32-bit word are the first four hex digits.

Passage of a data packet between two network nodes (for example, between two routers). See also hop count.

Routing metric used to measure the distance between a source and a destination.

Hypertext Transfer Protocol. Used by web browsers and web servers to transfer files, such as text and graphic files. HTTP is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. Relative to the TCP/IP suite of protocols (which are the basis for information exchange on the Internet), HTTP is an application protocol.

	Cisco IOS XR Getting Started Guide
GL-4	OL-10957-02