GL-1
Cisco IOS XR Getting Started Guide
OL-10957-02

GLOSSARY

A
AAA authentication, authorization, and accounting. A network security service that provides the primary
framework to set up access control on a CiscoCRS-1 router or access server. AAA is an architectural
framework and modular means of configuring three independent but closely related security functions
in a consistent manner.
ACL access control list. A list kept by routers to control access to or fr om the router for a number of services
(for example, to prevent packets with a certain IP address from leaving a particular interface on the
router).
active Denotes a card or process that performs a system task; in a redundant configuration , there is an inactive
standby card or process available to become active. Active cards or processes are also sometimes
denoted as primary.
active RP The RP that is active in a redundant pair of RPs.
active software
configuration
The software configuration marked as active for a node.
active software set The set of Cisco IOS XR software packages activated in one or more nodes in a router.
algorithm A well-defined rule or process for arriving at a solution to a problem. In networking, algorithms
commonly are used to determine the best route for tr affic from a particular source to a particular
destination.
APS automatic protection switching. A method that allows transmission equipment to recover automatically
from failures, such as a cut cable.
ASIC application-specific integrated circuit. A chip designed for use in a specific hardware device. An ASIC
is a chip designed for a special application, such as a pa rticular kind of transmission protocol.
B
bandwidth The amount of data that can be sent in a fixed amount of time. For digital devices, the bandwidth is
usually expressed in bits per second (Bps) or bytes per second.
BGP Border Gateway Protocol. A routing protocol used between autonomous systems. It is the routing
protocol that makes the internet work. BGP is a distance-vector rou ting protocol that carries
connectivity information and an additional set of BGP attributes. These attributes allow for a rich set
of policies for deciding the best route to use to reach a given destination.